Timing-driven placement and the first wire delays

See wire capacitance enter a timing report for the first time, explain why it costs more than wire resistance on short nets, and win the slack back with timing-driven placement and repair_timing.

Lesson
L4.5
Time
35 min
Runs on
OpenROAD
Check
5 questions

The MAC met a 4.6 ns clock with 0.3041 ns to spare in STA on the netlist. After global placement, with each net's wire estimated, the same path had a slack of -0.1371 ns. Not one cell or connection had changed: the wires had arrived.

Timing pathThe worst path after global placement, with wiresFrom the accumulator's flop through the adder's carry chain to another accumulator flop, after global placement.

_809_ → _827_setup check, latest arrival16 cells

  • Clock latency
  • Cell delay
  • Wire delay
  • Setup time
The worst path after global placement, with wires00.511.522.533.544.5time (ns)launch clk ↑capture clk ↑Data arrivesRequired by_809_/CLK → _809_/Q (dfrtp_1): 0.3844 ns1_809_/Q → _607_/A: 0.0002 ns_607_/A → _607_/Y (xnor2_1): 0.2200 ns2_607_/Y → _619_/A2: 0.0001 ns_619_/A2 → _619_/Y (o21ai_0): 0.1720 ns3_619_/Y → _641_/C: 0.0002 ns_641_/C → _641_/X (maj3_1): 0.4277 ns4_641_/X → _663_/C: 0.0003 ns_663_/C → _663_/X (maj3_1): 0.4101 ns5_663_/X → _685_/C: 0.0002 ns_685_/C → _685_/X (maj3_1): 0.4107 ns6_685_/X → _707_/C: 0.0003 ns_707_/C → _707_/X (maj3_1): 0.4222 ns7_707_/X → _727_/A1: 0.0003 ns_727_/A1 → _727_/Y (a211oi_1): 0.3093 ns8_727_/Y → _729_/A3: 0.0002 ns_729_/A3 → _729_/Y (o31ai_1): 0.1727 ns9_729_/Y → _731_/A2: 0.0004 ns_731_/A2 → _731_/X (o211a_1): 0.2483 ns10_731_/X → _734_/A3: 0.0002 ns_734_/A3 → _734_/Y (o311ai_0): 0.5155 ns11_734_/Y → _736_/A3: 0.0003 ns_736_/A3 → _736_/Y (a31oi_1): 0.2184 ns12_736_/Y → _737_/A2: 0.0002 ns_737_/A2 → _737_/Y (a21oi_1): 0.3057 ns13_737_/Y → _740_/A2: 0.0003 ns_740_/A2 → _740_/Y (a211oi_1): 0.1879 ns14_740_/Y → _742_/C: 0.0003 ns_742_/C → _742_/Y (nand3_1): 0.1316 ns_742_/Y → _748_/B: 0.0001 ns_748_/B → _748_/Y (xnor2_1): 0.1148 ns_748_/Y → _827_/D: 0.0001 nssetup −0.0823 nsslack −0.1371 ns · violatedarrival 4.6549required 4.5177The worst path after global placement, with wires01234time (ns)launch clk ↑capture clk ↑Data arrivesRequired by_809_/CLK → _809_/Q (dfrtp_1): 0.3844 ns1_809_/Q → _607_/A: 0.0002 ns_607_/A → _607_/Y (xnor2_1): 0.2200 ns2_607_/Y → _619_/A2: 0.0001 ns_619_/A2 → _619_/Y (o21ai_0): 0.1720 ns_619_/Y → _641_/C: 0.0002 ns_641_/C → _641_/X (maj3_1): 0.4277 ns4_641_/X → _663_/C: 0.0003 ns_663_/C → _663_/X (maj3_1): 0.4101 ns5_663_/X → _685_/C: 0.0002 ns_685_/C → _685_/X (maj3_1): 0.4107 ns6_685_/X → _707_/C: 0.0003 ns_707_/C → _707_/X (maj3_1): 0.4222 ns7_707_/X → _727_/A1: 0.0003 ns_727_/A1 → _727_/Y (a211oi_1): 0.3093 ns8_727_/Y → _729_/A3: 0.0002 ns_729_/A3 → _729_/Y (o31ai_1): 0.1727 ns_729_/Y → _731_/A2: 0.0004 ns_731_/A2 → _731_/X (o211a_1): 0.2483 ns_731_/X → _734_/A3: 0.0002 ns_734_/A3 → _734_/Y (o311ai_0): 0.5155 ns11_734_/Y → _736_/A3: 0.0003 ns_736_/A3 → _736_/Y (a31oi_1): 0.2184 ns_736_/Y → _737_/A2: 0.0002 ns_737_/A2 → _737_/Y (a21oi_1): 0.3057 ns13_737_/Y → _740_/A2: 0.0003 ns_740_/A2 → _740_/Y (a211oi_1): 0.1879 ns_740_/Y → _742_/C: 0.0003 ns_742_/C → _742_/Y (nand3_1): 0.1316 ns_742_/Y → _748_/B: 0.0001 ns_748_/B → _748_/Y (xnor2_1): 0.1148 ns_748_/Y → _827_/D: 0.0001 nssetup −0.0823 nsslack −0.1371 ns · violatedarrival 4.6549required 4.5177
  1. The shared cells take longer in total

    The cells drive wire now as well as pins. Over the 16 cells this path shares with the netlist's worst path, the delay grew by 0.4353 ns.

  2. Violated

    Slack -0.1371 ns, against 0.3041 ns before placement.

Read the path as a table

Launch: clk rise edge at 0.0000 ns, clock latency 0.0000 ns (ideal). Capture: clk rise edge at 4.6000 ns, latency 0.0000 ns, library setup time −0.0823 ns.

Arrival 4.6549 ns, required 4.5177 ns, slack −0.1371 ns (violated).

CellArcThroughEdgeDelay (ns)Time (ns)Slew (ns)
1_809_/CLK → _809_/Qdfrtp_1fall0.38440.38440.0797
_809_/Q → _607_/Awire acc[1]fall0.00020.38460.0797
2_607_/A → _607_/Yxnor2_1rise0.22000.60460.1940
_607_/Y → _619_/A2wire _080_rise0.00010.60470.1940
3_619_/A2 → _619_/Yo21ai_0fall0.17200.77670.1428
_619_/Y → _641_/Cwire _081_fall0.00020.77690.1428
4_641_/C → _641_/Xmaj3_1fall0.42771.20460.1041
_641_/X → _663_/Cwire _083_fall0.00031.20490.1041
5_663_/C → _663_/Xmaj3_1fall0.41011.61500.1002
_663_/X → _685_/Cwire _085_fall0.00021.61530.1002
6_685_/C → _685_/Xmaj3_1fall0.41072.02600.1017
_685_/X → _707_/Cwire _087_fall0.00032.02620.1017
7_707_/C → _707_/Xmaj3_1fall0.42222.44850.1119
_707_/X → _727_/A1wire _089_fall0.00032.44880.1119
8_727_/A1 → _727_/Ya211oi_1rise0.30932.75810.2965
_727_/Y → _729_/A3wire _093_rise0.00022.75820.2965
9_729_/A3 → _729_/Yo31ai_1fall0.17272.93100.1170
_729_/Y → _731_/A2wire _095_fall0.00042.93130.1170
10_731_/A2 → _731_/Xo211a_1fall0.24833.17960.0557
_731_/X → _734_/A3wire _097_fall0.00023.17980.0557
11_734_/A3 → _734_/Yo311ai_0rise0.51553.69530.5886
_734_/Y → _736_/A3wire _100_rise0.00033.69560.5886
12_736_/A3 → _736_/Ya31oi_1fall0.21843.91400.1495
_736_/Y → _737_/A2wire _101_fall0.00023.91410.1495
13_737_/A2 → _737_/Ya21oi_1rise0.30574.21980.2757
_737_/Y → _740_/A2wire _102_rise0.00034.22010.2757
14_740_/A2 → _740_/Ya211oi_1fall0.18794.40800.1324
_740_/Y → _742_/Cwire _105_fall0.00034.40830.1324
15_742_/C → _742_/Ynand3_1rise0.13164.53990.0857
_742_/Y → _748_/Bwire _107_rise0.00014.54000.0857
16_748_/B → _748_/Yxnor2_1rise0.11484.65480.1121
_748_/Y → _827_/Dwire _048_rise0.00014.65490.1121
The report
Startpoint: _809_ (rising edge-triggered flip-flop clocked by clk)
Endpoint: _827_ (rising edge-triggered flip-flop clocked by clk)
Path Group: clk
Path Type: max

Fanout       Cap      Slew     Delay      Time   Description
-------------------------------------------------------------------------------------
                    0.0000    0.0000    0.0000   clock clk (rise edge)
                              0.0000    0.0000   clock network delay (ideal)
                    0.0000    0.0000    0.0000 ^ _809_/CLK (sky130_fd_sc_hd__dfrtp_1)
     4    0.0122    0.0797    0.3844    0.3844 v _809_/Q (sky130_fd_sc_hd__dfrtp_1)
                                                 acc[1] (net)
                    0.0797    0.0002    0.3846 v _607_/A (sky130_fd_sc_hd__xnor2_1)
     2    0.0069    0.1940    0.2200    0.6046 ^ _607_/Y (sky130_fd_sc_hd__xnor2_1)
                                                 _080_ (net)
                    0.1940    0.0001    0.6047 ^ _619_/A2 (sky130_fd_sc_hd__o21ai_0)
     2    0.0098    0.1428    0.1720    0.7767 v _619_/Y (sky130_fd_sc_hd__o21ai_0)
                                                 _081_ (net)
                    0.1428    0.0002    0.7769 v _641_/C (sky130_fd_sc_hd__maj3_1)
     2    0.0105    0.1041    0.4277    1.2046 v _641_/X (sky130_fd_sc_hd__maj3_1)
                                                 _083_ (net)
                    0.1041    0.0003    1.2049 v _663_/C (sky130_fd_sc_hd__maj3_1)
     2    0.0096    0.1002    0.4101    1.6150 v _663_/X (sky130_fd_sc_hd__maj3_1)
                                                 _085_ (net)
                    0.1002    0.0002    1.6153 v _685_/C (sky130_fd_sc_hd__maj3_1)
     2    0.0100    0.1017    0.4107    2.0260 v _685_/X (sky130_fd_sc_hd__maj3_1)
                                                 _087_ (net)
                    0.1017    0.0003    2.0262 v _707_/C (sky130_fd_sc_hd__maj3_1)
     3    0.0122    0.1119    0.4222    2.4485 v _707_/X (sky130_fd_sc_hd__maj3_1)
                                                 _089_ (net)
                    0.1119    0.0003    2.4488 v _727_/A1 (sky130_fd_sc_hd__a211oi_1)
     2    0.0071    0.2965    0.3093    2.7581 ^ _727_/Y (sky130_fd_sc_hd__a211oi_1)
                                                 _093_ (net)
                    0.2965    0.0002    2.7582 ^ _729_/A3 (sky130_fd_sc_hd__o31ai_1)
     3    0.0124    0.1170    0.1727    2.9310 v _729_/Y (sky130_fd_sc_hd__o31ai_1)
                                                 _095_ (net)
                    0.1170    0.0004    2.9313 v _731_/A2 (sky130_fd_sc_hd__o211a_1)
     2    0.0066    0.0557    0.2483    3.1796 v _731_/X (sky130_fd_sc_hd__o211a_1)
                                                 _097_ (net)
                    0.0557    0.0002    3.1798 v _734_/A3 (sky130_fd_sc_hd__o311ai_0)
     3    0.0100    0.5886    0.5155    3.6953 ^ _734_/Y (sky130_fd_sc_hd__o311ai_0)
                                                 _100_ (net)
                    0.5886    0.0003    3.6956 ^ _736_/A3 (sky130_fd_sc_hd__a31oi_1)
     2    0.0085    0.1495    0.2184    3.9140 v _736_/Y (sky130_fd_sc_hd__a31oi_1)
                                                 _101_ (net)
                    0.1495    0.0002    3.9141 v _737_/A2 (sky130_fd_sc_hd__a21oi_1)
     3    0.0120    0.2757    0.3057    4.2198 ^ _737_/Y (sky130_fd_sc_hd__a21oi_1)
                                                 _102_ (net)
                    0.2757    0.0003    4.2201 ^ _740_/A2 (sky130_fd_sc_hd__a211oi_1)
     4    0.0132    0.1324    0.1879    4.4080 v _740_/Y (sky130_fd_sc_hd__a211oi_1)
                                                 _105_ (net)
                    0.1324    0.0003    4.4083 v _742_/C (sky130_fd_sc_hd__nand3_1)
     1    0.0054    0.0857    0.1316    4.5399 ^ _742_/Y (sky130_fd_sc_hd__nand3_1)
                                                 _107_ (net)
                    0.0857    0.0001    4.5400 ^ _748_/B (sky130_fd_sc_hd__xnor2_1)
     1    0.0026    0.1121    0.1148    4.6548 ^ _748_/Y (sky130_fd_sc_hd__xnor2_1)
                                                 _048_ (net)
                    0.1121    0.0001    4.6549 ^ _827_/D (sky130_fd_sc_hd__dfrtp_1)
                                        4.6549   data arrival time

                    0.0000    4.6000    4.6000   clock clk (rise edge)
                              0.0000    4.6000   clock network delay (ideal)
                              0.0000    4.6000   clock reconvergence pessimism
                                        4.6000 ^ _827_/CLK (sky130_fd_sc_hd__dfrtp_1)
                             -0.0823    4.5177   library setup time
                                        4.5177   data required time
-------------------------------------------------------------------------------------
                                        4.5177   data required time
                                       -4.6549   data arrival time
-------------------------------------------------------------------------------------
                                       -0.1371   slack (VIOLATED)

OpenROAD 26Q2 on sky130hd, MAC W=8 at 40 % utilization, after global placement with estimate_parasitics -placement.

A wire for every net

Estimated parasitics are the resistance and capacitance of a wire that is not routed yet. After placement every pin has a position, so estimate_parasitics -placement can build a Steiner tree for each net (L4.1) and give it resistance and capacitance per µm.

The per-µm values come from the platform's setRC.tcl, in the Liberty's units. Signal nets are estimated as met1: 0.172375 fF and 1.205650 Ω per µm. Clock nets use met3. Take 100 µm of met1 driven by an inv_1 into one flop's D pin, with a 0.05 ns input slew.

No wireWith 100 µm of met1
Load on the inverter1.678 fF1.678 fF + 17.238 fF = 18.915 fF
inv_1 rising delay (table lookup)0.0442 ns0.1425 ns
RC delay of the wire itself, 0.5 × R × C—0.5 × 120.6 Ω × 17.238 fF = 1.04 ps

Wire values from setRC.tcl; inv_1 cell_rise and the dfxtp_1 D capacitance from the pinned Liberty, looked up as in L2.2.

The wire's capacitance adds 0.0982 ns to the inverter; its unloaded distributed-wire estimate is 1.0 ps. A far-end pin load adds R·Cpin to that simple wire model. On short nets in this technology the cost of a wire is its capacitance. The driving cell has to charge it, so the cell gets slower.

Where the slack went

Put the netlist's worst path beside the placed one. Both run from _809_ to _827_, and 16 of the placed path's 16 cells are on both. The shared cells kept their order and changed only their loads and delays.

Timing pathThe same path before placement, no wires

_809_ → _827_setup check, latest arrival16 cells

  • Clock latency
  • Cell delay
  • Setup time
The same path before placement, no wires00.511.522.533.544.5time (ns)launch clk ↑capture clk ↑Data arrivesRequired by_809_/CLK → _809_/Q (dfrtp_1): 0.3700 ns1_607_/A → _607_/Y (xnor2_1): 0.2090 ns2_619_/A2 → _619_/Y (o21ai_0): 0.1481 ns3_641_/C → _641_/X (maj3_1): 0.3990 ns4_663_/C → _663_/X (maj3_1): 0.3921 ns5_685_/C → _685_/X (maj3_1): 0.3921 ns6_707_/C → _707_/X (maj3_1): 0.4037 ns7_727_/A1 → _727_/Y (a211oi_1): 0.2652 ns8_729_/A3 → _729_/Y (o31ai_1): 0.1414 ns9_731_/A2 → _731_/X (o211a_1): 0.2244 ns10_734_/A3 → _734_/Y (o311ai_0): 0.4243 ns11_736_/A3 → _736_/Y (a31oi_1): 0.1878 ns12_737_/A2 → _737_/Y (a21oi_1): 0.2650 ns13_740_/A2 → _740_/Y (a211oi_1): 0.1644 ns14_742_/C → _742_/Y (nand3_1): 0.1214 ns_748_/B → _748_/Y (xnor2_1): 0.1081 nssetup −0.0799 nsslack +0.3041 ns · metarrival 4.2159required 4.5201The same path before placement, no wires01234time (ns)launch clk ↑capture clk ↑Data arrivesRequired by_809_/CLK → _809_/Q (dfrtp_1): 0.3700 ns1_607_/A → _607_/Y (xnor2_1): 0.2090 ns2_619_/A2 → _619_/Y (o21ai_0): 0.1481 ns_641_/C → _641_/X (maj3_1): 0.3990 ns4_663_/C → _663_/X (maj3_1): 0.3921 ns5_685_/C → _685_/X (maj3_1): 0.3921 ns6_707_/C → _707_/X (maj3_1): 0.4037 ns7_727_/A1 → _727_/Y (a211oi_1): 0.2652 ns8_729_/A3 → _729_/Y (o31ai_1): 0.1414 ns_731_/A2 → _731_/X (o211a_1): 0.2244 ns_734_/A3 → _734_/Y (o311ai_0): 0.4243 ns11_736_/A3 → _736_/Y (a31oi_1): 0.1878 ns_737_/A2 → _737_/Y (a21oi_1): 0.2650 ns_740_/A2 → _740_/Y (a211oi_1): 0.1644 ns_742_/C → _742_/Y (nand3_1): 0.1214 ns_748_/B → _748_/Y (xnor2_1): 0.1081 nssetup −0.0799 nsslack +0.3041 ns · metarrival 4.2159required 4.5201
  1. Before placement

    Slack 0.3041 ns: pin capacitance only.

Read the path as a table

Launch: clk rise edge at 0.0000 ns, clock latency 0.0000 ns (ideal). Capture: clk rise edge at 4.6000 ns, latency 0.0000 ns, library setup time −0.0799 ns.

Arrival 4.2159 ns, required 4.5201 ns, slack 0.3041 ns (met).

CellArcThroughEdgeDelay (ns)Time (ns)Slew (ns)
1_809_/CLK → _809_/Qdfrtp_1fall0.37000.37000.0674
_809_/Q → _607_/Awire acc[1]fall0.00000.37000.0674
2_607_/A → _607_/Yxnor2_1rise0.20900.57900.1928
_607_/Y → _619_/A2wire _080_rise0.00000.57900.1928
3_619_/A2 → _619_/Yo21ai_0fall0.14810.72710.1149
_619_/Y → _641_/Cwire _081_fall0.00000.72710.1149
4_641_/C → _641_/Xmaj3_1fall0.39901.12600.0920
_641_/X → _663_/Cwire _083_fall0.00001.12600.0920
5_663_/C → _663_/Xmaj3_1fall0.39211.51820.0920
_663_/X → _685_/Cwire _085_fall0.00001.51820.0920
6_685_/C → _685_/Xmaj3_1fall0.39211.91030.0920
_685_/X → _707_/Cwire _087_fall0.00001.91030.0920
7_707_/C → _707_/Xmaj3_1fall0.40372.31400.1013
_707_/X → _727_/A1wire _089_fall0.00002.31400.1013
8_727_/A1 → _727_/Ya211oi_1rise0.26522.57920.2531
_727_/Y → _729_/A3wire _093_rise0.00002.57920.2531
9_729_/A3 → _729_/Yo31ai_1fall0.14142.72060.0941
_729_/Y → _731_/A2wire _095_fall0.00002.72060.0941
10_731_/A2 → _731_/Xo211a_1fall0.22442.94500.0449
_731_/X → _734_/A3wire _097_fall0.00002.94500.0449
11_734_/A3 → _734_/Yo311ai_0rise0.42433.36920.4921
_734_/Y → _736_/A3wire _100_rise0.00003.36920.4921
12_736_/A3 → _736_/Ya31oi_1fall0.18783.55700.1296
_736_/Y → _737_/A2wire _101_fall0.00003.55700.1296
13_737_/A2 → _737_/Ya21oi_1rise0.26503.82200.2375
_737_/Y → _740_/A2wire _102_rise0.00003.82200.2375
14_740_/A2 → _740_/Ya211oi_1fall0.16443.98650.1196
_740_/Y → _742_/Cwire _105_fall0.00003.98650.1196
15_742_/C → _742_/Ynand3_1rise0.12144.10780.0801
_742_/Y → _748_/Bwire _107_rise0.00004.10780.0801
16_748_/B → _748_/Yxnor2_1rise0.10814.21590.1022
_748_/Y → _827_/Dwire _048_rise0.00004.21590.1022
The report
Startpoint: _809_ (rising edge-triggered flip-flop clocked by clk)
Endpoint: _827_ (rising edge-triggered flip-flop clocked by clk)
Path Group: clk
Path Type: max

Fanout       Cap      Slew     Delay      Time   Description
-------------------------------------------------------------------------------------
                    0.0000    0.0000    0.0000   clock clk (rise edge)
                              0.0000    0.0000   clock network delay (ideal)
                    0.0000    0.0000    0.0000 ^ _809_/CLK (sky130_fd_sc_hd__dfrtp_1)
     4    0.0088    0.0674    0.3700    0.3700 v _809_/Q (sky130_fd_sc_hd__dfrtp_1)
                                                 acc[1] (net)
                    0.0674    0.0000    0.3700 v _607_/A (sky130_fd_sc_hd__xnor2_1)
     2    0.0065    0.1928    0.2090    0.5790 ^ _607_/Y (sky130_fd_sc_hd__xnor2_1)
                                                 _080_ (net)
                    0.1928    0.0000    0.5790 ^ _619_/A2 (sky130_fd_sc_hd__o21ai_0)
     2    0.0073    0.1149    0.1481    0.7271 v _619_/Y (sky130_fd_sc_hd__o21ai_0)
                                                 _081_ (net)
                    0.1149    0.0000    0.7271 v _641_/C (sky130_fd_sc_hd__maj3_1)
     2    0.0073    0.0920    0.3990    1.1260 v _641_/X (sky130_fd_sc_hd__maj3_1)
                                                 _083_ (net)
                    0.0920    0.0000    1.1260 v _663_/C (sky130_fd_sc_hd__maj3_1)
     2    0.0073    0.0920    0.3921    1.5182 v _663_/X (sky130_fd_sc_hd__maj3_1)
                                                 _085_ (net)
                    0.0920    0.0000    1.5182 v _685_/C (sky130_fd_sc_hd__maj3_1)
     2    0.0073    0.0920    0.3921    1.9103 v _685_/X (sky130_fd_sc_hd__maj3_1)
                                                 _087_ (net)
                    0.0920    0.0000    1.9103 v _707_/C (sky130_fd_sc_hd__maj3_1)
     3    0.0090    0.1013    0.4037    2.3140 v _707_/X (sky130_fd_sc_hd__maj3_1)
                                                 _089_ (net)
                    0.1013    0.0000    2.3140 v _727_/A1 (sky130_fd_sc_hd__a211oi_1)
     2    0.0052    0.2531    0.2652    2.5792 ^ _727_/Y (sky130_fd_sc_hd__a211oi_1)
                                                 _093_ (net)
                    0.2531    0.0000    2.5792 ^ _729_/A3 (sky130_fd_sc_hd__o31ai_1)
     3    0.0088    0.0941    0.1414    2.7206 v _729_/Y (sky130_fd_sc_hd__o31ai_1)
                                                 _095_ (net)
                    0.0941    0.0000    2.7206 v _731_/A2 (sky130_fd_sc_hd__o211a_1)
     2    0.0038    0.0449    0.2244    2.9450 v _731_/X (sky130_fd_sc_hd__o211a_1)
                                                 _097_ (net)
                    0.0449    0.0000    2.9450 v _734_/A3 (sky130_fd_sc_hd__o311ai_0)
     3    0.0073    0.4921    0.4243    3.3692 ^ _734_/Y (sky130_fd_sc_hd__o311ai_0)
                                                 _100_ (net)
                    0.4921    0.0000    3.3692 ^ _736_/A3 (sky130_fd_sc_hd__a31oi_1)
     2    0.0067    0.1296    0.1878    3.5570 v _736_/Y (sky130_fd_sc_hd__a31oi_1)
                                                 _101_ (net)
                    0.1296    0.0000    3.5570 v _737_/A2 (sky130_fd_sc_hd__a21oi_1)
     3    0.0096    0.2375    0.2650    3.8220 ^ _737_/Y (sky130_fd_sc_hd__a21oi_1)
                                                 _102_ (net)
                    0.2375    0.0000    3.8220 ^ _740_/A2 (sky130_fd_sc_hd__a211oi_1)
     4    0.0109    0.1196    0.1644    3.9865 v _740_/Y (sky130_fd_sc_hd__a211oi_1)
                                                 _105_ (net)
                    0.1196    0.0000    3.9865 v _742_/C (sky130_fd_sc_hd__nand3_1)
     1    0.0047    0.0801    0.1214    4.1078 ^ _742_/Y (sky130_fd_sc_hd__nand3_1)
                                                 _107_ (net)
                    0.0801    0.0000    4.1078 ^ _748_/B (sky130_fd_sc_hd__xnor2_1)
     1    0.0020    0.1022    0.1081    4.2159 ^ _748_/Y (sky130_fd_sc_hd__xnor2_1)
                                                 _048_ (net)
                    0.1022    0.0000    4.2159 ^ _827_/D (sky130_fd_sc_hd__dfrtp_1)
                                        4.2159   data arrival time

                    0.0000    4.6000    4.6000   clock clk (rise edge)
                              0.0000    4.6000   clock network delay (ideal)
                              0.0000    4.6000   clock reconvergence pessimism
                                        4.6000 ^ _827_/CLK (sky130_fd_sc_hd__dfrtp_1)
                             -0.0799    4.5201   library setup time
                                        4.5201   data required time
-------------------------------------------------------------------------------------
                                        4.5201   data required time
                                       -4.2159   data arrival time
-------------------------------------------------------------------------------------
                                        0.3041   slack (MET)

OpenSTA 3.1.0 on the netlist, ideal clock, no wires.

The biggest change is _734_/Y (o311ai_0): its load went from 7.3 fF to 10 fF, so about 16 µm of met1 by the per-µm value, and its delay from 0.4243 ns to 0.5155 ns. The net arcs, the wires' own RC delay, add only 0.0037 ns along the whole path.

Effective capacitance: what the driver really sees

A resistive wire hides part of its far-end capacitance from the driver: while the near end switches, the far end is still charging through the wire's resistance. OpenSTA therefore computes an effective capacitance for the driver, smaller than the total, and looks up the cell delay with it. It then adds a separate wire delay from the driver pin to each load pin. Those are the two numbers a report shows: the cell arc and the net arc.

For the short met1 nets of this block the effective and total capacitance are nearly equal, because the wire's resistance is small. On long or thin wires the difference grows, and so does the net arc.

Timing-driven placement

global_placement -timing_driven gives the placer the timing it lacked. At set overflow points during placement it runs a quick STA with estimated wires, finds the nets on the worst paths, and raises their weight in the wirelength cost. The placer then pulls those nets' cells closer, at some cost to the others.

In this OpenROAD version timing-driven placement can retain repairs below its configured overflow threshold: the MAC grew from 583 to 587 instances during placement, 4 new cells.

LayoutThe MAC placed timing-drivenThe same netlist, clock, utilization and density, with -timing_driven.
  • Tap cells
  • Logic
  • Buffers and inverters
  • Flip-flops
  • I/O pins
Stage
Detailed placement
Cell area
4,362.9 µm²
Utilization
42.6 %
Wirelength (HPWL)
6,119 µm
Worst max slack
0.1629 ns
Total negative max slack
0.0000 ns
Worst min slack
0.4865 ns
The MAC placed timing-drivenDrawing the layout…
  1. Timing-driven global placement

    Worst slack 0.2145 ns with wires estimated, against -0.1371 ns for the wirelength-driven placement. HPWL 5086 µm against 4952 µm.

  2. Legalized

    After legalization: 0.1629 ns.

Read the layout as text

mac: die 112.02 × 112.02 µm, core 101.66 × 100.64 µm, 37 rows of 2.72 µm, 39 signal pins.

StageCell areaUtilizationWirelength (HPWL)Worst max slackTotal negative max slackWorst min slackOverflowCells placed
Floorplan4,332.9 µm²42.4 %—0.3041 ns0.0000 ns0.4243 ns—136 tap cells; I/O pins not placed yet
Global placement4,362.9 µm²42.6 %5,086 µm0.2145 ns0.0000 ns0.4482 ns0.0998136 tap cells, 10 buffers and inverters, 389 logic, 52 flip-flops
Detailed placement4,362.9 µm²42.6 %6,119 µm0.1629 ns0.0000 ns0.4865 ns—136 tap cells, 10 buffers and inverters, 389 logic, 52 flip-flops

OpenROAD 26Q2 on sky130hd, MAC W=8 at 40 % utilization, density 0.6, 4.6 ns clock.

The placement is a little longer in total and better where it matters. That is the trade: wirelength on non-critical nets bought slack on critical ones.

repair_timing -setup

repair_timing -setup works on a placed design. It walks the worst paths and tries moves on their cells until the slack target is met or nothing helps:

  1. Resize

    A stronger driver for a slow cell, or a smaller cell that loads its driver less.

  2. Buffer

    Split the non-critical loads off a critical net behind a buffer, or rebuffer the net.

  3. Swap pins

    Move the late signal to the faster input of a commutative gate (L2.1's A and B).

  4. Clone

    Copy a gate that drives two critical paths, so each copy drives one.

On the wirelength-driven placement it changed 1 cell size(s) and added 0 buffers. The flow then legalized its changes again. Read the rows in order:

StepWNSTNS
Netlist, no wires0.3041 ns0.0000 ns
Global placement, wires estimated-0.1371 ns-0.3753 ns
repair_design, then legalization-0.2361 ns-0.8895 ns
repair_timing -setup, legalized again0.0560 ns0.0000 ns
Timing-driven placement, legalized0.1629 ns0.0000 ns

The MAC at 4.6 ns. repair_design found nothing to fix at this SDC; legalization alone moved the slack.

The wirelength-driven run with both repairs
LayoutThe MAC with repair_design and repair_timing
  • Tap cells
  • Logic
  • Buffers and inverters
  • Flip-flops
  • I/O pins
Stage
Detailed placement
Cell area
4,340.4 µm²
Utilization
42.4 %
Wirelength (HPWL)
6,051 µm
Worst max slack
0.0560 ns
Total negative max slack
0.0000 ns
Worst min slack
0.4534 ns
The MAC with repair_design and repair_timingDrawing the layout…
  1. Wirelength-driven

    Worst slack -0.1371 ns.

  2. Repaired and legal

    Worst slack 0.0560 ns.

Read the layout as text

mac: die 112.02 × 112.02 µm, core 101.66 × 100.64 µm, 37 rows of 2.72 µm, 39 signal pins.

StageCell areaUtilizationWirelength (HPWL)Worst max slackTotal negative max slackWorst min slackOverflowCells placed
Floorplan4,332.9 µm²42.4 %—0.3041 ns0.0000 ns0.4243 ns—136 tap cells; I/O pins not placed yet
Global placement4,332.9 µm²42.4 %4,952 µm−0.1371 ns−0.3753 ns0.4496 ns0.0994136 tap cells, 6 buffers and inverters, 389 logic, 52 flip-flops
Detailed placement4,340.4 µm²42.4 %6,051 µm0.0560 ns0.0000 ns0.4534 ns—136 tap cells, 6 buffers and inverters, 389 logic, 52 flip-flops

OpenROAD 26Q2 on sky130hd: repair_design, detailed_placement, repair_timing -setup, detailed_placement.

These passes may add buffers and change combinational gate depth, but they do not move registers or add pipeline stages. When the moves run out, the fix goes back to the RTL: pipelining (R4.5) or retiming (R4.6).

This flow defers hold repair until CTS. Pre-CTS hold analysis is useful, but its ideal clocks omit the eventual skew; inserted delays may need revision after CTS (L5).

Asked in interviews
  1. How does placement affect timing?

    It decides the wire on every net. On short nets the wire's capacitance slows the driving cell; on long nets its resistance adds a wire delay. Spread-out critical paths lose slack.

  2. What does a timing-driven placer do?

    It runs STA with estimated wires during placement and raises the weight of nets on critical paths, so their cells end up closer. Some placers also resize or buffer on the way.

  3. How do you fix a setup violation after placement?

    Resize cells on the path, buffer off non-critical loads, swap pins, clone drivers, re-place timing-driven; if none is enough, pipeline or retime in the RTL.

  4. Why not fix hold before CTS?

    Early hold checks help planning, but the actual tree changes skew. This flow sizes hold repair after CTS and checks its setup cost.

Try it

The timing-driven run of the MAC at 4.6 ns. Output lists the worst slack per stage: 0.3041 ns on the netlist, 0.2145 ns after global placement, 0.1629 ns after legalization. Paths draws the worst path with its wires.

Tighten the clock in the SDC to 4.3 ns and run again. Then raise the density to 0.9: cells cluster, and the critical nets get shorter or longer. Which way does the slack move?

FLOWOpenROAD 26Q2 · sky130hd · simulator service
Edit the constraints, then run them

          
Expected: global placement WNS 0.2145 ns detailed placement WNS 0.1629 ns
Read the netlist: mac.v (the bundled design mac8)
/* Generated by Yosys 0.70+290 (git sha1 e8968a4f7, Release, Clang /usr/bin/clang++ 21.1.8) */

module mac(clk, rst_n, en, a, b, acc);
  input clk;
  wire clk;
  input rst_n;
  wire rst_n;
  input en;
  wire en;
  input [7:0] a;
  wire [7:0] a;
  input [7:0] b;
  wire [7:0] b;
  output [19:0] acc;
  wire [19:0] acc;
  wire _000_;
  wire _001_;
  wire _002_;
  wire _003_;
  wire _004_;
  wire _005_;
  wire _006_;
  wire _007_;
  wire _008_;
  wire _009_;
  wire _010_;
  wire _011_;
  wire _012_;
  wire _013_;
  wire _014_;
  wire _015_;
  wire _016_;
  wire _017_;
  wire _018_;
  wire _019_;
  wire _020_;
  wire _021_;
  wire _022_;
  wire _023_;
  wire _024_;
  wire _025_;
  wire _026_;
  wire _027_;
  wire _028_;
  wire _029_;
  wire _030_;
  wire _031_;
  wire _032_;
  wire _033_;
  wire _034_;
  wire _035_;
  wire _036_;
  wire _037_;
  wire _038_;
  wire _039_;
  wire _040_;
  wire _041_;
  wire _042_;
  wire _043_;
  wire _044_;
  wire _045_;
  wire _046_;
  wire _047_;
  wire _048_;
  wire _049_;
  wire _050_;
  wire _051_;
  wire _052_;
  wire _053_;
  wire _054_;
  wire _055_;
  wire _056_;
  wire _057_;
  wire _058_;
  wire _059_;
  wire _060_;
  wire _061_;
  wire _062_;
  wire _063_;
  wire _064_;
  wire _065_;
  wire _066_;
  wire _067_;
  wire _068_;
  wire _069_;
  wire _070_;
  wire _071_;
  wire _072_;
  wire _073_;
  wire _074_;
  wire _075_;
  wire _076_;
  wire _077_;
  wire _078_;
  wire _079_;
  wire _080_;
  wire _081_;
  wire _082_;
  wire _083_;
  wire _084_;
  wire _085_;
  wire _086_;
  wire _087_;
  wire _088_;
  wire _089_;
  wire _090_;
  wire _091_;
  wire _092_;
  wire _093_;
  wire _094_;
  wire _095_;
  wire _096_;
  wire _097_;
  wire _098_;
  wire _099_;
  wire _100_;
  wire _101_;
  wire _102_;
  wire _103_;
  wire _104_;
  wire _105_;
  wire _106_;
  wire _107_;
  wire _108_;
  wire _109_;
  wire _110_;
  wire _111_;
  wire _112_;
  wire _113_;
  wire _114_;
  wire _115_;
  wire _116_;
  wire _117_;
  wire _118_;
  wire _119_;
  wire _120_;
  wire _121_;
  wire _122_;
  wire _123_;
  wire _124_;
  wire _125_;
  wire _126_;
  wire _127_;
  wire _128_;
  wire _129_;
  wire _130_;
  wire _131_;
  wire _132_;
  wire _133_;
  wire _134_;
  wire _135_;
  wire _136_;
  wire _137_;
  wire _138_;
  wire _139_;
  wire _140_;
  wire _141_;
  wire _142_;
  wire _143_;
  wire _144_;
  wire _145_;
  wire _146_;
  wire _147_;
  wire _148_;
  wire _149_;
  wire _150_;
  wire _151_;
  wire _152_;
  wire _153_;
  wire _154_;
  wire _155_;
  wire _156_;
  wire _157_;
  wire _158_;
  wire _159_;
  wire _160_;
  wire _161_;
  wire _162_;
  wire _163_;
  wire _164_;
  wire _165_;
  wire _166_;
  wire _167_;
  wire _168_;
  wire _169_;
  wire _170_;
  wire _171_;
  wire _172_;
  wire _173_;
  wire _174_;
  wire _175_;
  wire _176_;
  wire _177_;
  wire _178_;
  wire _179_;
  wire _180_;
  wire _181_;
  wire _182_;
  wire _183_;
  wire _184_;
  wire _185_;
  wire _186_;
  wire _187_;
  wire _188_;
  wire _189_;
  wire _190_;
  wire _191_;
  wire _192_;
  wire _193_;
  wire _194_;
  wire _195_;
  wire _196_;
  wire _197_;
  wire _198_;
  wire _199_;
  wire _200_;
  wire _201_;
  wire _202_;
  wire _203_;
  wire _204_;
  wire _205_;
  wire _206_;
  wire _207_;
  wire _208_;
  wire _209_;
  wire _210_;
  wire _211_;
  wire _212_;
  wire _213_;
  wire _214_;
  wire _215_;
  wire _216_;
  wire _217_;
  wire _218_;
  wire _219_;
  wire _220_;
  wire _221_;
  wire _222_;
  wire _223_;
  wire _224_;
  wire _225_;
  wire _226_;
  wire _227_;
  wire _228_;
  wire _229_;
  wire _230_;
  wire _231_;
  wire _232_;
  wire _233_;
  wire _234_;
  wire _235_;
  wire _236_;
  wire _237_;
  wire _238_;
  wire _239_;
  wire _240_;
  wire _241_;
  wire _242_;
  wire _243_;
  wire _244_;
  wire _245_;
  wire _246_;
  wire _247_;
  wire _248_;
  wire _249_;
  wire _250_;
  wire _251_;
  wire _252_;
  wire _253_;
  wire _254_;
  wire _255_;
  wire _256_;
  wire _257_;
  wire _258_;
  wire _259_;
  wire _260_;
  wire _261_;
  wire _262_;
  wire _263_;
  wire _264_;
  wire _265_;
  wire _266_;
  wire _267_;
  wire _268_;
  wire _269_;
  wire _270_;
  wire _271_;
  wire _272_;
  wire _273_;
  wire _274_;
  wire _275_;
  wire _276_;
  wire _277_;
  wire _278_;
  wire _279_;
  wire _280_;
  wire _281_;
  wire _282_;
  wire _283_;
  wire _284_;
  wire _285_;
  wire _286_;
  wire _287_;
  wire _288_;
  wire _289_;
  wire _290_;
  wire _291_;
  wire _292_;
  wire _293_;
  wire _294_;
  wire _295_;
  wire _296_;
  wire _297_;
  wire _298_;
  wire _299_;
  wire _300_;
  wire _301_;
  wire _302_;
  wire _303_;
  wire _304_;
  wire _305_;
  wire _306_;
  wire _307_;
  wire _308_;
  wire _309_;
  wire _310_;
  wire _311_;
  wire _312_;
  wire _313_;
  wire _314_;
  wire _315_;
  wire _316_;
  wire _317_;
  wire _318_;
  wire _319_;
  wire _320_;
  wire _321_;
  wire _322_;
  wire _323_;
  wire _324_;
  wire _325_;
  wire _326_;
  wire _327_;
  wire _328_;
  wire _329_;
  wire _330_;
  wire _331_;
  wire _332_;
  wire _333_;
  wire _334_;
  wire _335_;
  wire _336_;
  wire _337_;
  wire _338_;
  wire _339_;
  wire _340_;
  wire _341_;
  wire _342_;
  wire _343_;
  wire _344_;
  wire _345_;
  wire _346_;
  wire _347_;
  wire _348_;
  wire _349_;
  wire _350_;
  wire _351_;
  wire _352_;
  wire _353_;
  wire _354_;
  wire _355_;
  wire _356_;
  wire _357_;
  wire _358_;
  wire _359_;
  wire _360_;
  wire _361_;
  wire _362_;
  wire _363_;
  wire _364_;
  wire _365_;
  wire _366_;
  wire _367_;
  wire _368_;
  wire _369_;
  wire _370_;
  wire _371_;
  wire _372_;
  wire _373_;
  wire _374_;
  wire _375_;
  wire _376_;
  wire _377_;
  wire _378_;
  wire _379_;
  wire _380_;
  wire _381_;
  wire _382_;
  wire _383_;
  wire _384_;
  wire _385_;
  wire _386_;
  wire _387_;
  wire _388_;
  wire _389_;
  wire _390_;
  wire _391_;
  wire _392_;
  wire _393_;
  wire _394_;
  wire \p[0] ;
  wire \p[10] ;
  wire \p[11] ;
  wire \p[12] ;
  wire \p[13] ;
  wire \p[14] ;
  wire \p[15] ;
  wire \p[1] ;
  wire \p[2] ;
  wire \p[3] ;
  wire \p[4] ;
  wire \p[5] ;
  wire \p[6] ;
  wire \p[7] ;
  wire \p[8] ;
  wire \p[9] ;
  wire \ra[0] ;
  wire \ra[1] ;
  wire \ra[2] ;
  wire \ra[3] ;
  wire \ra[4] ;
  wire \ra[5] ;
  wire \ra[6] ;
  wire \ra[7] ;
  wire \rb[0] ;
  wire \rb[1] ;
  wire \rb[2] ;
  wire \rb[3] ;
  wire \rb[4] ;
  wire \rb[5] ;
  wire \rb[6] ;
  wire \rb[7] ;
  sky130_fd_sc_hd__clkinv_1 _395_ (
    .A(en),
    .Y(_052_)
  );
  sky130_fd_sc_hd__clkinv_1 _396_ (
    .A(acc[16]),
    .Y(_053_)
  );
  sky130_fd_sc_hd__xnor2_1 _397_ (
    .A(acc[12]),
    .B(\p[12] ),
    .Y(_061_)
  );
  sky130_fd_sc_hd__xor3_1 _398_ (
    .A(_112_),
    .B(_145_),
    .C(_146_),
    .X(_148_)
  );
  sky130_fd_sc_hd__nand2_1 _399_ (
    .A(_144_),
    .B(_148_),
    .Y(_149_)
  );
  sky130_fd_sc_hd__nand3_1 _400_ (
    .A(\ra[7] ),
    .B(\rb[2] ),
    .C(_149_),
    .Y(_150_)
  );
  sky130_fd_sc_hd__xnor2_1 _401_ (
    .A(_115_),
    .B(_116_),
    .Y(_151_)
  );
  sky130_fd_sc_hd__nand2_1 _402_ (
    .A(\rb[7] ),
    .B(\ra[3] ),
    .Y(_152_)
  );
  sky130_fd_sc_hd__maj3_1 _403_ (
    .A(_112_),
    .B(_145_),
    .C(_146_),
    .X(_153_)
  );
  sky130_fd_sc_hd__nand2_1 _404_ (
    .A(\ra[4] ),
    .B(\rb[6] ),
    .Y(_154_)
  );
  sky130_fd_sc_hd__xnor2_1 _405_ (
    .A(_153_),
    .B(_154_),
    .Y(_155_)
  );
  sky130_fd_sc_hd__xnor2_1 _406_ (
    .A(_152_),
    .B(_155_),
    .Y(_156_)
  );
  sky130_fd_sc_hd__maj3_1 _407_ (
    .A(_150_),
    .B(_151_),
    .C(_156_),
    .X(_157_)
  );
  sky130_fd_sc_hd__clkinv_1 _408_ (
    .A(_061_),
    .Y(_062_)
  );
  sky130_fd_sc_hd__xnor2_1 _409_ (
    .A(_120_),
    .B(_124_),
    .Y(_158_)
  );
  sky130_fd_sc_hd__nor2b_1 _410_ (
    .A(_157_),
    .B_N(_158_),
    .Y(_159_)
  );
  sky130_fd_sc_hd__maj3_1 _411_ (
    .A(_152_),
    .B(_153_),
    .C(_154_),
    .X(_160_)
  );
  sky130_fd_sc_hd__xnor2_1 _412_ (
    .A(_157_),
    .B(_158_),
    .Y(_161_)
  );
  sky130_fd_sc_hd__nor2b_1 _413_ (
    .A(_160_),
    .B_N(_161_),
    .Y(_162_)
  );
  sky130_fd_sc_hd__xor2_1 _414_ (
    .A(_135_),
    .B(_136_),
    .X(_163_)
  );
  sky130_fd_sc_hd__o21a_1 _415_ (
    .A1(_159_),
    .A2(_162_),
    .B1(_163_),
    .X(_164_)
  );
  sky130_fd_sc_hd__nand2_1 _416_ (
    .A(\ra[7] ),
    .B(\rb[1] ),
    .Y(_165_)
  );
  sky130_fd_sc_hd__and2_0 _417_ (
    .A(\ra[6] ),
    .B(\rb[0] ),
    .X(_166_)
  );
  sky130_fd_sc_hd__nand2_1 _418_ (
    .A(\ra[7] ),
    .B(\rb[0] ),
    .Y(_167_)
  );
  sky130_fd_sc_hd__and2_0 _419_ (
    .A(acc[11]),
    .B(\p[11] ),
    .X(_063_)
  );
  sky130_fd_sc_hd__nand2_1 _420_ (
    .A(\ra[5] ),
    .B(\rb[2] ),
    .Y(_168_)
  );
  sky130_fd_sc_hd__maj3_1 _421_ (
    .A(_144_),
    .B(_167_),
    .C(_168_),
    .X(_169_)
  );
  sky130_fd_sc_hd__nand2_1 _422_ (
    .A(\ra[6] ),
    .B(\rb[2] ),
    .Y(_170_)
  );
  sky130_fd_sc_hd__xnor2_1 _423_ (
    .A(_165_),
    .B(_170_),
    .Y(_171_)
  );
  sky130_fd_sc_hd__nand2_1 _424_ (
    .A(\ra[3] ),
    .B(\rb[5] ),
    .Y(_172_)
  );
  sky130_fd_sc_hd__nand2_1 _425_ (
    .A(\ra[4] ),
    .B(\rb[4] ),
    .Y(_173_)
  );
  sky130_fd_sc_hd__nand2_1 _426_ (
    .A(\ra[4] ),
    .B(\rb[3] ),
    .Y(_174_)
  );
  sky130_fd_sc_hd__xor3_1 _427_ (
    .A(_147_),
    .B(_172_),
    .C(_173_),
    .X(_175_)
  );
  sky130_fd_sc_hd__maj3_1 _428_ (
    .A(_169_),
    .B(_171_),
    .C(_175_),
    .X(_176_)
  );
  sky130_fd_sc_hd__nand3_1 _429_ (
    .A(\ra[7] ),
    .B(\rb[2] ),
    .C(_144_),
    .Y(_177_)
  );
  sky130_fd_sc_hd__nand2_1 _430_ (
    .A(acc[11]),
    .B(\p[11] ),
    .Y(_064_)
  );
  sky130_fd_sc_hd__xnor2_1 _431_ (
    .A(_148_),
    .B(_177_),
    .Y(_178_)
  );
  sky130_fd_sc_hd__nand2_1 _432_ (
    .A(\rb[7] ),
    .B(\ra[2] ),
    .Y(_179_)
  );
  sky130_fd_sc_hd__maj3_1 _433_ (
    .A(_147_),
    .B(_172_),
    .C(_173_),
    .X(_180_)
  );
  sky130_fd_sc_hd__nand2_1 _434_ (
    .A(\ra[3] ),
    .B(\rb[6] ),
    .Y(_181_)
  );
  sky130_fd_sc_hd__xnor2_1 _435_ (
    .A(_180_),
    .B(_181_),
    .Y(_182_)
  );
  sky130_fd_sc_hd__xnor2_1 _436_ (
    .A(_179_),
    .B(_182_),
    .Y(_183_)
  );
  sky130_fd_sc_hd__xnor2_1 _437_ (
    .A(_176_),
    .B(_178_),
    .Y(_184_)
  );
  sky130_fd_sc_hd__maj3_1 _438_ (
    .A(_176_),
    .B(_178_),
    .C(_183_),
    .X(_185_)
  );
  sky130_fd_sc_hd__xor3_1 _439_ (
    .A(_150_),
    .B(_151_),
    .C(_156_),
    .X(_186_)
  );
  sky130_fd_sc_hd__maj3_1 _440_ (
    .A(_179_),
    .B(_180_),
    .C(_181_),
    .X(_187_)
  );
  sky130_fd_sc_hd__nor2_1 _441_ (
    .A(acc[11]),
    .B(\p[11] ),
    .Y(_065_)
  );
  sky130_fd_sc_hd__xor2_1 _442_ (
    .A(_185_),
    .B(_186_),
    .X(_188_)
  );
  sky130_fd_sc_hd__maj3_1 _443_ (
    .A(_185_),
    .B(_186_),
    .C(_187_),
    .X(_189_)
  );
  sky130_fd_sc_hd__xor2_1 _444_ (
    .A(_160_),
    .B(_161_),
    .X(_190_)
  );
  sky130_fd_sc_hd__nor2_1 _445_ (
    .A(_189_),
    .B(_190_),
    .Y(_191_)
  );
  sky130_fd_sc_hd__nand2_1 _446_ (
    .A(\ra[5] ),
    .B(\rb[0] ),
    .Y(_192_)
  );
  sky130_fd_sc_hd__and2_0 _447_ (
    .A(\ra[5] ),
    .B(\rb[1] ),
    .X(_193_)
  );
  sky130_fd_sc_hd__and2_0 _448_ (
    .A(\ra[4] ),
    .B(\rb[2] ),
    .X(_194_)
  );
  sky130_fd_sc_hd__maj3_1 _449_ (
    .A(_166_),
    .B(_193_),
    .C(_194_),
    .X(_195_)
  );
  sky130_fd_sc_hd__xnor3_1 _450_ (
    .A(_144_),
    .B(_167_),
    .C(_168_),
    .X(_196_)
  );
  sky130_fd_sc_hd__nand2_1 _451_ (
    .A(\ra[2] ),
    .B(\rb[5] ),
    .Y(_197_)
  );
  sky130_fd_sc_hd__clkinv_1 _452_ (
    .A(_065_),
    .Y(_066_)
  );
  sky130_fd_sc_hd__nand2_1 _453_ (
    .A(\ra[3] ),
    .B(\rb[4] ),
    .Y(_198_)
  );
  sky130_fd_sc_hd__nand2_1 _454_ (
    .A(\ra[3] ),
    .B(\rb[3] ),
    .Y(_199_)
  );
  sky130_fd_sc_hd__xnor3_1 _455_ (
    .A(_174_),
    .B(_197_),
    .C(_198_),
    .X(_200_)
  );
  sky130_fd_sc_hd__maj3_1 _456_ (
    .A(_195_),
    .B(_196_),
    .C(_200_),
    .X(_201_)
  );
  sky130_fd_sc_hd__xnor3_1 _457_ (
    .A(_169_),
    .B(_171_),
    .C(_175_),
    .X(_202_)
  );
  sky130_fd_sc_hd__nand2_1 _458_ (
    .A(\rb[7] ),
    .B(\ra[1] ),
    .Y(_203_)
  );
  sky130_fd_sc_hd__maj3_1 _459_ (
    .A(_174_),
    .B(_197_),
    .C(_198_),
    .X(_204_)
  );
  sky130_fd_sc_hd__nand2_1 _460_ (
    .A(\ra[2] ),
    .B(\rb[6] ),
    .Y(_205_)
  );
  sky130_fd_sc_hd__xor2_1 _461_ (
    .A(_204_),
    .B(_205_),
    .X(_206_)
  );
  sky130_fd_sc_hd__xnor2_1 _462_ (
    .A(_203_),
    .B(_206_),
    .Y(_207_)
  );
  sky130_fd_sc_hd__and2_0 _463_ (
    .A(acc[10]),
    .B(\p[10] ),
    .X(_067_)
  );
  sky130_fd_sc_hd__xor2_1 _464_ (
    .A(_201_),
    .B(_202_),
    .X(_208_)
  );
  sky130_fd_sc_hd__maj3_1 _465_ (
    .A(_201_),
    .B(_202_),
    .C(_207_),
    .X(_209_)
  );
  sky130_fd_sc_hd__xnor2_1 _466_ (
    .A(_183_),
    .B(_184_),
    .Y(_210_)
  );
  sky130_fd_sc_hd__nand2b_1 _467_ (
    .A_N(_210_),
    .B(_209_),
    .Y(_211_)
  );
  sky130_fd_sc_hd__maj3_1 _468_ (
    .A(_203_),
    .B(_204_),
    .C(_205_),
    .X(_212_)
  );
  sky130_fd_sc_hd__xnor2_1 _469_ (
    .A(_209_),
    .B(_210_),
    .Y(_213_)
  );
  sky130_fd_sc_hd__nand2b_1 _470_ (
    .A_N(_212_),
    .B(_213_),
    .Y(_214_)
  );
  sky130_fd_sc_hd__and2_0 _471_ (
    .A(_211_),
    .B(_214_),
    .X(_215_)
  );
  sky130_fd_sc_hd__xor2_1 _472_ (
    .A(_187_),
    .B(_188_),
    .X(_216_)
  );
  sky130_fd_sc_hd__nor2_1 _473_ (
    .A(_215_),
    .B(_216_),
    .Y(_217_)
  );
  sky130_fd_sc_hd__nor2_1 _474_ (
    .A(acc[10]),
    .B(\p[10] ),
    .Y(_068_)
  );
  sky130_fd_sc_hd__nand2_1 _475_ (
    .A(\ra[4] ),
    .B(\rb[1] ),
    .Y(_218_)
  );
  sky130_fd_sc_hd__and2_0 _476_ (
    .A(\ra[4] ),
    .B(\rb[0] ),
    .X(_219_)
  );
  sky130_fd_sc_hd__nand2_1 _477_ (
    .A(\ra[3] ),
    .B(\rb[2] ),
    .Y(_220_)
  );
  sky130_fd_sc_hd__maj3_1 _478_ (
    .A(_192_),
    .B(_218_),
    .C(_220_),
    .X(_221_)
  );
  sky130_fd_sc_hd__xnor3_1 _479_ (
    .A(_166_),
    .B(_193_),
    .C(_194_),
    .X(_222_)
  );
  sky130_fd_sc_hd__nand2_1 _480_ (
    .A(\ra[1] ),
    .B(\rb[5] ),
    .Y(_223_)
  );
  sky130_fd_sc_hd__nand2_1 _481_ (
    .A(\ra[2] ),
    .B(\rb[4] ),
    .Y(_224_)
  );
  sky130_fd_sc_hd__nand2_1 _482_ (
    .A(\ra[2] ),
    .B(\rb[3] ),
    .Y(_225_)
  );
  sky130_fd_sc_hd__xor3_1 _483_ (
    .A(_199_),
    .B(_223_),
    .C(_224_),
    .X(_226_)
  );
  sky130_fd_sc_hd__maj3_1 _484_ (
    .A(_221_),
    .B(_222_),
    .C(_226_),
    .X(_227_)
  );
  sky130_fd_sc_hd__nor2_1 _485_ (
    .A(_067_),
    .B(_068_),
    .Y(_069_)
  );
  sky130_fd_sc_hd__xnor3_1 _486_ (
    .A(_195_),
    .B(_196_),
    .C(_200_),
    .X(_228_)
  );
  sky130_fd_sc_hd__nand2_1 _487_ (
    .A(\rb[7] ),
    .B(\ra[0] ),
    .Y(_229_)
  );
  sky130_fd_sc_hd__maj3_1 _488_ (
    .A(_199_),
    .B(_223_),
    .C(_224_),
    .X(_230_)
  );
  sky130_fd_sc_hd__nand2_1 _489_ (
    .A(\ra[1] ),
    .B(\rb[6] ),
    .Y(_231_)
  );
  sky130_fd_sc_hd__xor3_1 _490_ (
    .A(_229_),
    .B(_230_),
    .C(_231_),
    .X(_232_)
  );
  sky130_fd_sc_hd__xnor2_1 _491_ (
    .A(_227_),
    .B(_228_),
    .Y(_233_)
  );
  sky130_fd_sc_hd__maj3_1 _492_ (
    .A(_227_),
    .B(_228_),
    .C(_232_),
    .X(_234_)
  );
  sky130_fd_sc_hd__xnor2_1 _493_ (
    .A(_207_),
    .B(_208_),
    .Y(_235_)
  );
  sky130_fd_sc_hd__nor2_1 _494_ (
    .A(_234_),
    .B(_235_),
    .Y(_236_)
  );
  sky130_fd_sc_hd__maj3_1 _495_ (
    .A(_229_),
    .B(_230_),
    .C(_231_),
    .X(_237_)
  );
  sky130_fd_sc_hd__and2_0 _496_ (
    .A(acc[9]),
    .B(\p[9] ),
    .X(_070_)
  );
  sky130_fd_sc_hd__xor3_1 _497_ (
    .A(_207_),
    .B(_208_),
    .C(_234_),
    .X(_238_)
  );
  sky130_fd_sc_hd__nor2_1 _498_ (
    .A(_237_),
    .B(_238_),
    .Y(_239_)
  );
  sky130_fd_sc_hd__nor2_1 _499_ (
    .A(_236_),
    .B(_239_),
    .Y(_240_)
  );
  sky130_fd_sc_hd__xnor2_1 _500_ (
    .A(_212_),
    .B(_213_),
    .Y(_241_)
  );
  sky130_fd_sc_hd__o21ai_0 _501_ (
    .A1(_236_),
    .A2(_239_),
    .B1(_241_),
    .Y(_242_)
  );
  sky130_fd_sc_hd__and2_0 _502_ (
    .A(\ra[3] ),
    .B(\rb[1] ),
    .X(_243_)
  );
  sky130_fd_sc_hd__nand2_1 _503_ (
    .A(\ra[3] ),
    .B(\rb[0] ),
    .Y(_244_)
  );
  sky130_fd_sc_hd__and2_0 _504_ (
    .A(\ra[2] ),
    .B(\rb[2] ),
    .X(_245_)
  );
  sky130_fd_sc_hd__maj3_1 _505_ (
    .A(_219_),
    .B(_243_),
    .C(_245_),
    .X(_246_)
  );
  sky130_fd_sc_hd__xnor3_1 _506_ (
    .A(_192_),
    .B(_218_),
    .C(_220_),
    .X(_247_)
  );
  sky130_fd_sc_hd__mux2_1 _507_ (
    .A0(\ra[7] ),
    .A1(a[7]),
    .S(en),
    .X(_051_)
  );
  sky130_fd_sc_hd__or2_0 _508_ (
    .A(acc[9]),
    .B(\p[9] ),
    .X(_071_)
  );
  sky130_fd_sc_hd__nand2_1 _509_ (
    .A(\ra[0] ),
    .B(\rb[5] ),
    .Y(_248_)
  );
  sky130_fd_sc_hd__nand2_1 _510_ (
    .A(\ra[1] ),
    .B(\rb[4] ),
    .Y(_249_)
  );
  sky130_fd_sc_hd__nand2_1 _511_ (
    .A(\ra[1] ),
    .B(\rb[3] ),
    .Y(_250_)
  );
  sky130_fd_sc_hd__xnor3_1 _512_ (
    .A(_225_),
    .B(_248_),
    .C(_249_),
    .X(_251_)
  );
  sky130_fd_sc_hd__maj3_1 _513_ (
    .A(_246_),
    .B(_247_),
    .C(_251_),
    .X(_252_)
  );
  sky130_fd_sc_hd__xnor3_1 _514_ (
    .A(_221_),
    .B(_222_),
    .C(_226_),
    .X(_253_)
  );
  sky130_fd_sc_hd__maj3_1 _515_ (
    .A(_225_),
    .B(_248_),
    .C(_249_),
    .X(_254_)
  );
  sky130_fd_sc_hd__nand2_1 _516_ (
    .A(\ra[0] ),
    .B(\rb[6] ),
    .Y(_255_)
  );
  sky130_fd_sc_hd__nor2_1 _517_ (
    .A(_254_),
    .B(_255_),
    .Y(_256_)
  );
  sky130_fd_sc_hd__xor2_1 _518_ (
    .A(_254_),
    .B(_255_),
    .X(_257_)
  );
  sky130_fd_sc_hd__nand2_1 _519_ (
    .A(acc[8]),
    .B(\p[8] ),
    .Y(_072_)
  );
  sky130_fd_sc_hd__xnor2_1 _520_ (
    .A(_252_),
    .B(_253_),
    .Y(_258_)
  );
  sky130_fd_sc_hd__maj3_1 _521_ (
    .A(_252_),
    .B(_253_),
    .C(_257_),
    .X(_259_)
  );
  sky130_fd_sc_hd__xor2_1 _522_ (
    .A(_232_),
    .B(_233_),
    .X(_260_)
  );
  sky130_fd_sc_hd__xor2_1 _523_ (
    .A(_259_),
    .B(_260_),
    .X(_261_)
  );
  sky130_fd_sc_hd__maj3_1 _524_ (
    .A(_256_),
    .B(_259_),
    .C(_260_),
    .X(_262_)
  );
  sky130_fd_sc_hd__xor2_1 _525_ (
    .A(_237_),
    .B(_238_),
    .X(_263_)
  );
  sky130_fd_sc_hd__nand2_1 _526_ (
    .A(_262_),
    .B(_263_),
    .Y(_264_)
  );
  sky130_fd_sc_hd__xnor2_1 _527_ (
    .A(_262_),
    .B(_263_),
    .Y(_265_)
  );
  sky130_fd_sc_hd__xnor2_1 _528_ (
    .A(_256_),
    .B(_261_),
    .Y(_266_)
  );
  sky130_fd_sc_hd__nand2_1 _529_ (
    .A(\ra[2] ),
    .B(\rb[1] ),
    .Y(_267_)
  );
  sky130_fd_sc_hd__nor2_1 _530_ (
    .A(acc[8]),
    .B(\p[8] ),
    .Y(_073_)
  );
  sky130_fd_sc_hd__nand2_1 _531_ (
    .A(\ra[2] ),
    .B(\rb[0] ),
    .Y(_268_)
  );
  sky130_fd_sc_hd__nand2_1 _532_ (
    .A(\ra[1] ),
    .B(\rb[2] ),
    .Y(_269_)
  );
  sky130_fd_sc_hd__xnor2_1 _533_ (
    .A(_244_),
    .B(_267_),
    .Y(_270_)
  );
  sky130_fd_sc_hd__maj3_1 _534_ (
    .A(_244_),
    .B(_267_),
    .C(_269_),
    .X(_271_)
  );
  sky130_fd_sc_hd__xnor3_1 _535_ (
    .A(_219_),
    .B(_243_),
    .C(_245_),
    .X(_272_)
  );
  sky130_fd_sc_hd__nand2_1 _536_ (
    .A(\ra[0] ),
    .B(\rb[4] ),
    .Y(_273_)
  );
  sky130_fd_sc_hd__nand2_1 _537_ (
    .A(\ra[0] ),
    .B(\rb[3] ),
    .Y(_274_)
  );
  sky130_fd_sc_hd__nor2_1 _538_ (
    .A(_250_),
    .B(_273_),
    .Y(_275_)
  );
  sky130_fd_sc_hd__xnor2_1 _539_ (
    .A(_250_),
    .B(_273_),
    .Y(_276_)
  );
  sky130_fd_sc_hd__maj3_1 _540_ (
    .A(_271_),
    .B(_272_),
    .C(_276_),
    .X(_277_)
  );
  sky130_fd_sc_hd__xor2_1 _541_ (
    .A(acc[8]),
    .B(\p[8] ),
    .X(_074_)
  );
  sky130_fd_sc_hd__clkinv_1 _542_ (
    .A(_277_),
    .Y(_278_)
  );
  sky130_fd_sc_hd__xor3_1 _543_ (
    .A(_246_),
    .B(_247_),
    .C(_251_),
    .X(_279_)
  );
  sky130_fd_sc_hd__xor2_1 _544_ (
    .A(_277_),
    .B(_279_),
    .X(_280_)
  );
  sky130_fd_sc_hd__maj3_1 _545_ (
    .A(_275_),
    .B(_278_),
    .C(_279_),
    .X(_281_)
  );
  sky130_fd_sc_hd__xnor2_1 _546_ (
    .A(_257_),
    .B(_258_),
    .Y(_282_)
  );
  sky130_fd_sc_hd__nand2_1 _547_ (
    .A(_281_),
    .B(_282_),
    .Y(_283_)
  );
  sky130_fd_sc_hd__xnor2_1 _548_ (
    .A(_281_),
    .B(_282_),
    .Y(_284_)
  );
  sky130_fd_sc_hd__nand2_1 _549_ (
    .A(\ra[1] ),
    .B(\rb[1] ),
    .Y(_285_)
  );
  sky130_fd_sc_hd__nand2_1 _550_ (
    .A(\ra[0] ),
    .B(\rb[2] ),
    .Y(_286_)
  );
  sky130_fd_sc_hd__xor2_1 _551_ (
    .A(_268_),
    .B(_285_),
    .X(_287_)
  );
  sky130_fd_sc_hd__and2_0 _552_ (
    .A(acc[7]),
    .B(\p[7] ),
    .X(_075_)
  );
  sky130_fd_sc_hd__maj3_1 _553_ (
    .A(_268_),
    .B(_285_),
    .C(_286_),
    .X(_288_)
  );
  sky130_fd_sc_hd__xnor2_1 _554_ (
    .A(_269_),
    .B(_270_),
    .Y(_289_)
  );
  sky130_fd_sc_hd__maj3_1 _555_ (
    .A(_274_),
    .B(_288_),
    .C(_289_),
    .X(_290_)
  );
  sky130_fd_sc_hd__xnor3_1 _556_ (
    .A(_271_),
    .B(_272_),
    .C(_276_),
    .X(_291_)
  );
  sky130_fd_sc_hd__nand2b_1 _557_ (
    .A_N(_290_),
    .B(_291_),
    .Y(_292_)
  );
  sky130_fd_sc_hd__xnor2_1 _558_ (
    .A(_275_),
    .B(_280_),
    .Y(_293_)
  );
  sky130_fd_sc_hd__nand2b_1 _559_ (
    .A_N(_292_),
    .B(_293_),
    .Y(_294_)
  );
  sky130_fd_sc_hd__nand2_1 _560_ (
    .A(\ra[0] ),
    .B(\rb[0] ),
    .Y(_295_)
  );
  sky130_fd_sc_hd__nand4_1 _561_ (
    .A(\ra[0] ),
    .B(\ra[1] ),
    .C(\rb[0] ),
    .D(\rb[1] ),
    .Y(_296_)
  );
  sky130_fd_sc_hd__xnor2_1 _562_ (
    .A(_286_),
    .B(_287_),
    .Y(_297_)
  );
  sky130_fd_sc_hd__nor2_1 _563_ (
    .A(acc[7]),
    .B(\p[7] ),
    .Y(_076_)
  );
  sky130_fd_sc_hd__nand2b_1 _564_ (
    .A_N(_296_),
    .B(_297_),
    .Y(_298_)
  );
  sky130_fd_sc_hd__xor3_1 _565_ (
    .A(_274_),
    .B(_288_),
    .C(_289_),
    .X(_299_)
  );
  sky130_fd_sc_hd__nor2_1 _566_ (
    .A(_298_),
    .B(_299_),
    .Y(_300_)
  );
  sky130_fd_sc_hd__nand2b_1 _567_ (
    .A_N(_291_),
    .B(_290_),
    .Y(_301_)
  );
  sky130_fd_sc_hd__and2_0 _568_ (
    .A(_292_),
    .B(_301_),
    .X(_302_)
  );
  sky130_fd_sc_hd__nand2_1 _569_ (
    .A(_300_),
    .B(_302_),
    .Y(_303_)
  );
  sky130_fd_sc_hd__xor2_1 _570_ (
    .A(_292_),
    .B(_293_),
    .X(_304_)
  );
  sky130_fd_sc_hd__nand4_1 _571_ (
    .A(_292_),
    .B(_293_),
    .C(_300_),
    .D(_301_),
    .Y(_305_)
  );
  sky130_fd_sc_hd__a21o_1 _572_ (
    .A1(_294_),
    .A2(_305_),
    .B1(_284_),
    .X(_306_)
  );
  sky130_fd_sc_hd__a21oi_1 _573_ (
    .A1(_283_),
    .A2(_306_),
    .B1(_266_),
    .Y(_307_)
  );
  sky130_fd_sc_hd__and2_0 _574_ (
    .A(acc[6]),
    .B(\p[6] ),
    .X(_077_)
  );
  sky130_fd_sc_hd__a211o_1 _575_ (
    .A1(_283_),
    .A2(_306_),
    .B1(_265_),
    .C1(_266_),
    .X(_308_)
  );
  sky130_fd_sc_hd__xor2_1 _576_ (
    .A(_240_),
    .B(_241_),
    .X(_309_)
  );
  sky130_fd_sc_hd__a21o_1 _577_ (
    .A1(_264_),
    .A2(_308_),
    .B1(_309_),
    .X(_310_)
  );
  sky130_fd_sc_hd__nand2_1 _578_ (
    .A(_242_),
    .B(_310_),
    .Y(_311_)
  );
  sky130_fd_sc_hd__xor2_1 _579_ (
    .A(_215_),
    .B(_216_),
    .X(_312_)
  );
  sky130_fd_sc_hd__a21boi_0 _580_ (
    .A1(_242_),
    .A2(_310_),
    .B1_N(_312_),
    .Y(_313_)
  );
  sky130_fd_sc_hd__xor2_1 _581_ (
    .A(_189_),
    .B(_190_),
    .X(_314_)
  );
  sky130_fd_sc_hd__o21a_1 _582_ (
    .A1(_217_),
    .A2(_313_),
    .B1(_314_),
    .X(_315_)
  );
  sky130_fd_sc_hd__nor3_1 _583_ (
    .A(_159_),
    .B(_162_),
    .C(_163_),
    .Y(_316_)
  );
  sky130_fd_sc_hd__nor2_1 _584_ (
    .A(_164_),
    .B(_316_),
    .Y(_317_)
  );
  sky130_fd_sc_hd__nand2_1 _585_ (
    .A(acc[1]),
    .B(\p[1] ),
    .Y(_078_)
  );
  sky130_fd_sc_hd__o21a_1 _586_ (
    .A1(_191_),
    .A2(_315_),
    .B1(_317_),
    .X(_318_)
  );
  sky130_fd_sc_hd__nand2_1 _587_ (
    .A(_137_),
    .B(_142_),
    .Y(_319_)
  );
  sky130_fd_sc_hd__nand2_1 _588_ (
    .A(_143_),
    .B(_319_),
    .Y(_320_)
  );
  sky130_fd_sc_hd__o21bai_1 _589_ (
    .A1(_164_),
    .A2(_318_),
    .B1_N(_320_),
    .Y(_321_)
  );
  sky130_fd_sc_hd__nand3_1 _590_ (
    .A(\ra[7] ),
    .B(\rb[7] ),
    .C(_127_),
    .Y(_322_)
  );
  sky130_fd_sc_hd__maj3_1 _591_ (
    .A(_133_),
    .B(_138_),
    .C(_140_),
    .X(_323_)
  );
  sky130_fd_sc_hd__xor2_1 _592_ (
    .A(_322_),
    .B(_323_),
    .X(_324_)
  );
  sky130_fd_sc_hd__a21o_1 _593_ (
    .A1(_143_),
    .A2(_321_),
    .B1(_324_),
    .X(_325_)
  );
  sky130_fd_sc_hd__o211ai_1 _594_ (
    .A1(_128_),
    .A2(_323_),
    .B1(\ra[7] ),
    .C1(\rb[7] ),
    .Y(_326_)
  );
  sky130_fd_sc_hd__a31oi_1 _595_ (
    .A1(en),
    .A2(_325_),
    .A3(_326_),
    .B1(_110_),
    .Y(_047_)
  );
  sky130_fd_sc_hd__nand2_1 _596_ (
    .A(acc[0]),
    .B(\p[0] ),
    .Y(_079_)
  );
  sky130_fd_sc_hd__mux2_1 _597_ (
    .A0(\rb[7] ),
    .A1(b[7]),
    .S(en),
    .X(_046_)
  );
  sky130_fd_sc_hd__mux2_1 _598_ (
    .A0(\ra[0] ),
    .A1(a[0]),
    .S(en),
    .X(_045_)
  );
  sky130_fd_sc_hd__mux2_1 _599_ (
    .A0(\ra[1] ),
    .A1(a[1]),
    .S(en),
    .X(_044_)
  );
  sky130_fd_sc_hd__mux2_1 _600_ (
    .A0(\ra[2] ),
    .A1(a[2]),
    .S(en),
    .X(_043_)
  );
  sky130_fd_sc_hd__mux2_1 _601_ (
    .A0(\ra[3] ),
    .A1(a[3]),
    .S(en),
    .X(_042_)
  );
  sky130_fd_sc_hd__mux2_1 _602_ (
    .A0(\ra[4] ),
    .A1(a[4]),
    .S(en),
    .X(_041_)
  );
  sky130_fd_sc_hd__mux2_1 _603_ (
    .A0(\ra[5] ),
    .A1(a[5]),
    .S(en),
    .X(_040_)
  );
  sky130_fd_sc_hd__mux2_1 _604_ (
    .A0(\ra[6] ),
    .A1(a[6]),
    .S(en),
    .X(_039_)
  );
  sky130_fd_sc_hd__xnor2_1 _605_ (
    .A(_062_),
    .B(_099_),
    .Y(_327_)
  );
  sky130_fd_sc_hd__nor2_1 _606_ (
    .A(en),
    .B(acc[12]),
    .Y(_328_)
  );
  sky130_fd_sc_hd__xnor2_1 _607_ (
    .A(acc[1]),
    .B(\p[1] ),
    .Y(_080_)
  );
  sky130_fd_sc_hd__a21oi_1 _608_ (
    .A1(en),
    .A2(_327_),
    .B1(_328_),
    .Y(_038_)
  );
  sky130_fd_sc_hd__xnor2_1 _609_ (
    .A(_069_),
    .B(_096_),
    .Y(_329_)
  );
  sky130_fd_sc_hd__nor2_1 _610_ (
    .A(en),
    .B(acc[10]),
    .Y(_330_)
  );
  sky130_fd_sc_hd__a21oi_1 _611_ (
    .A1(en),
    .A2(_329_),
    .B1(_330_),
    .Y(_037_)
  );
  sky130_fd_sc_hd__xnor2_1 _612_ (
    .A(_074_),
    .B(_094_),
    .Y(_331_)
  );
  sky130_fd_sc_hd__nor2_1 _613_ (
    .A(en),
    .B(acc[8]),
    .Y(_332_)
  );
  sky130_fd_sc_hd__a21oi_1 _614_ (
    .A1(en),
    .A2(_331_),
    .B1(_332_),
    .Y(_036_)
  );
  sky130_fd_sc_hd__xnor2_1 _615_ (
    .A(\p[15] ),
    .B(acc[15]),
    .Y(_333_)
  );
  sky130_fd_sc_hd__xnor2_1 _616_ (
    .A(_102_),
    .B(_333_),
    .Y(_334_)
  );
  sky130_fd_sc_hd__nor2_1 _617_ (
    .A(en),
    .B(acc[15]),
    .Y(_335_)
  );
  sky130_fd_sc_hd__nand2_1 _618_ (
    .A(\p[15] ),
    .B(acc[15]),
    .Y(_054_)
  );
  sky130_fd_sc_hd__o21ai_0 _619_ (
    .A1(_079_),
    .A2(_080_),
    .B1(_078_),
    .Y(_081_)
  );
  sky130_fd_sc_hd__a21oi_1 _620_ (
    .A1(en),
    .A2(_334_),
    .B1(_335_),
    .Y(_035_)
  );
  sky130_fd_sc_hd__xnor2_1 _621_ (
    .A(_089_),
    .B(_091_),
    .Y(_336_)
  );
  sky130_fd_sc_hd__nor2_1 _622_ (
    .A(en),
    .B(acc[6]),
    .Y(_337_)
  );
  sky130_fd_sc_hd__a21oi_1 _623_ (
    .A1(en),
    .A2(_336_),
    .B1(_337_),
    .Y(_034_)
  );
  sky130_fd_sc_hd__nor2_1 _624_ (
    .A(en),
    .B(acc[11]),
    .Y(_338_)
  );
  sky130_fd_sc_hd__nand2_1 _625_ (
    .A(_064_),
    .B(_066_),
    .Y(_339_)
  );
  sky130_fd_sc_hd__xnor2_1 _626_ (
    .A(_098_),
    .B(_339_),
    .Y(_340_)
  );
  sky130_fd_sc_hd__a21oi_1 _627_ (
    .A1(en),
    .A2(_340_),
    .B1(_338_),
    .Y(_033_)
  );
  sky130_fd_sc_hd__nor2b_1 _628_ (
    .A(en),
    .B_N(\p[14] ),
    .Y(_341_)
  );
  sky130_fd_sc_hd__nand3_1 _629_ (
    .A(_143_),
    .B(_321_),
    .C(_324_),
    .Y(_342_)
  );
  sky130_fd_sc_hd__xor2_1 _630_ (
    .A(acc[2]),
    .B(\p[2] ),
    .X(_082_)
  );
  sky130_fd_sc_hd__a31o_1 _631_ (
    .A1(en),
    .A2(_325_),
    .A3(_342_),
    .B1(_341_),
    .X(_032_)
  );
  sky130_fd_sc_hd__xnor2_1 _632_ (
    .A(_057_),
    .B(_101_),
    .Y(_343_)
  );
  sky130_fd_sc_hd__nor2_1 _633_ (
    .A(en),
    .B(acc[14]),
    .Y(_344_)
  );
  sky130_fd_sc_hd__a21oi_1 _634_ (
    .A1(en),
    .A2(_343_),
    .B1(_344_),
    .Y(_031_)
  );
  sky130_fd_sc_hd__nor2_1 _635_ (
    .A(acc[16]),
    .B(_104_),
    .Y(_345_)
  );
  sky130_fd_sc_hd__nor2_1 _636_ (
    .A(_105_),
    .B(_345_),
    .Y(_030_)
  );
  sky130_fd_sc_hd__xnor2_1 _637_ (
    .A(acc[13]),
    .B(\p[13] ),
    .Y(_346_)
  );
  sky130_fd_sc_hd__nand3_1 _638_ (
    .A(_060_),
    .B(_100_),
    .C(_346_),
    .Y(_347_)
  );
  sky130_fd_sc_hd__a21oi_1 _639_ (
    .A1(_060_),
    .A2(_100_),
    .B1(_346_),
    .Y(_348_)
  );
  sky130_fd_sc_hd__nor3b_1 _640_ (
    .A(_348_),
    .B(_052_),
    .C_N(_347_),
    .Y(_349_)
  );
  sky130_fd_sc_hd__maj3_1 _641_ (
    .A(acc[2]),
    .B(\p[2] ),
    .C(_081_),
    .X(_083_)
  );
  sky130_fd_sc_hd__a21o_1 _642_ (
    .A1(_052_),
    .A2(acc[13]),
    .B1(_349_),
    .X(_029_)
  );
  sky130_fd_sc_hd__xnor2_1 _643_ (
    .A(_079_),
    .B(_080_),
    .Y(_350_)
  );
  sky130_fd_sc_hd__nor2_1 _644_ (
    .A(en),
    .B(acc[1]),
    .Y(_351_)
  );
  sky130_fd_sc_hd__a21oi_1 _645_ (
    .A1(en),
    .A2(_350_),
    .B1(_351_),
    .Y(_028_)
  );
  sky130_fd_sc_hd__nor3b_1 _646_ (
    .A(_164_),
    .B(_318_),
    .C_N(_320_),
    .Y(_352_)
  );
  sky130_fd_sc_hd__nand2_1 _647_ (
    .A(en),
    .B(_321_),
    .Y(_353_)
  );
  sky130_fd_sc_hd__o2bb2ai_1 _648_ (
    .A1_N(_052_),
    .A2_N(\p[13] ),
    .B1(_352_),
    .B2(_353_),
    .Y(_027_)
  );
  sky130_fd_sc_hd__xnor2_1 _649_ (
    .A(_083_),
    .B(_084_),
    .Y(_354_)
  );
  sky130_fd_sc_hd__nor2_1 _650_ (
    .A(en),
    .B(acc[3]),
    .Y(_355_)
  );
  sky130_fd_sc_hd__a21oi_1 _651_ (
    .A1(en),
    .A2(_354_),
    .B1(_355_),
    .Y(_026_)
  );
  sky130_fd_sc_hd__xor2_1 _652_ (
    .A(acc[3]),
    .B(\p[3] ),
    .X(_084_)
  );
  sky130_fd_sc_hd__nand2_1 _653_ (
    .A(en),
    .B(\p[0] ),
    .Y(_356_)
  );
  sky130_fd_sc_hd__xnor2_1 _654_ (
    .A(acc[0]),
    .B(_356_),
    .Y(_025_)
  );
  sky130_fd_sc_hd__xnor2_1 _655_ (
    .A(_087_),
    .B(_088_),
    .Y(_357_)
  );
  sky130_fd_sc_hd__nor2_1 _656_ (
    .A(en),
    .B(acc[5]),
    .Y(_358_)
  );
  sky130_fd_sc_hd__a21oi_1 _657_ (
    .A1(en),
    .A2(_357_),
    .B1(_358_),
    .Y(_024_)
  );
  sky130_fd_sc_hd__nor3_1 _658_ (
    .A(_191_),
    .B(_315_),
    .C(_317_),
    .Y(_359_)
  );
  sky130_fd_sc_hd__nor3_1 _659_ (
    .A(_052_),
    .B(_318_),
    .C(_359_),
    .Y(_360_)
  );
  sky130_fd_sc_hd__a21o_1 _660_ (
    .A1(_052_),
    .A2(\p[12] ),
    .B1(_360_),
    .X(_023_)
  );
  sky130_fd_sc_hd__nor2_1 _661_ (
    .A(_075_),
    .B(_076_),
    .Y(_361_)
  );
  sky130_fd_sc_hd__xor2_1 _662_ (
    .A(_092_),
    .B(_361_),
    .X(_362_)
  );
  sky130_fd_sc_hd__maj3_1 _663_ (
    .A(acc[3]),
    .B(\p[3] ),
    .C(_083_),
    .X(_085_)
  );
  sky130_fd_sc_hd__mux2_1 _664_ (
    .A0(acc[7]),
    .A1(_362_),
    .S(en),
    .X(_022_)
  );
  sky130_fd_sc_hd__nor2b_1 _665_ (
    .A(_070_),
    .B_N(_071_),
    .Y(_363_)
  );
  sky130_fd_sc_hd__xnor2_1 _666_ (
    .A(_095_),
    .B(_363_),
    .Y(_364_)
  );
  sky130_fd_sc_hd__nor2_1 _667_ (
    .A(en),
    .B(acc[9]),
    .Y(_365_)
  );
  sky130_fd_sc_hd__a21oi_1 _668_ (
    .A1(en),
    .A2(_364_),
    .B1(_365_),
    .Y(_021_)
  );
  sky130_fd_sc_hd__xor2_1 _669_ (
    .A(acc[17]),
    .B(_105_),
    .X(_020_)
  );
  sky130_fd_sc_hd__xnor2_1 _670_ (
    .A(_081_),
    .B(_082_),
    .Y(_366_)
  );
  sky130_fd_sc_hd__nor2_1 _671_ (
    .A(en),
    .B(acc[2]),
    .Y(_367_)
  );
  sky130_fd_sc_hd__a21oi_1 _672_ (
    .A1(en),
    .A2(_366_),
    .B1(_367_),
    .Y(_019_)
  );
  sky130_fd_sc_hd__mux2_1 _673_ (
    .A0(\rb[0] ),
    .A1(b[0]),
    .S(en),
    .X(_018_)
  );
  sky130_fd_sc_hd__xor2_1 _674_ (
    .A(acc[4]),
    .B(\p[4] ),
    .X(_086_)
  );
  sky130_fd_sc_hd__mux2_1 _675_ (
    .A0(\rb[1] ),
    .A1(b[1]),
    .S(en),
    .X(_017_)
  );
  sky130_fd_sc_hd__mux2_1 _676_ (
    .A0(\rb[2] ),
    .A1(b[2]),
    .S(en),
    .X(_016_)
  );
  sky130_fd_sc_hd__mux2_1 _677_ (
    .A0(\rb[3] ),
    .A1(b[3]),
    .S(en),
    .X(_015_)
  );
  sky130_fd_sc_hd__mux2_1 _678_ (
    .A0(\rb[4] ),
    .A1(b[4]),
    .S(en),
    .X(_014_)
  );
  sky130_fd_sc_hd__mux2_1 _679_ (
    .A0(\rb[5] ),
    .A1(b[5]),
    .S(en),
    .X(_013_)
  );
  sky130_fd_sc_hd__mux2_1 _680_ (
    .A0(\rb[6] ),
    .A1(b[6]),
    .S(en),
    .X(_012_)
  );
  sky130_fd_sc_hd__nor2_1 _681_ (
    .A(en),
    .B(\p[0] ),
    .Y(_368_)
  );
  sky130_fd_sc_hd__a21oi_1 _682_ (
    .A1(en),
    .A2(_295_),
    .B1(_368_),
    .Y(_011_)
  );
  sky130_fd_sc_hd__a22oi_1 _683_ (
    .A1(\ra[1] ),
    .A2(\rb[0] ),
    .B1(\rb[1] ),
    .B2(\ra[0] ),
    .Y(_369_)
  );
  sky130_fd_sc_hd__nand2_1 _684_ (
    .A(en),
    .B(_296_),
    .Y(_370_)
  );
  sky130_fd_sc_hd__maj3_1 _685_ (
    .A(acc[4]),
    .B(\p[4] ),
    .C(_085_),
    .X(_087_)
  );
  sky130_fd_sc_hd__o2bb2ai_1 _686_ (
    .A1_N(_052_),
    .A2_N(\p[1] ),
    .B1(_369_),
    .B2(_370_),
    .Y(_010_)
  );
  sky130_fd_sc_hd__xor2_1 _687_ (
    .A(_296_),
    .B(_297_),
    .X(_371_)
  );
  sky130_fd_sc_hd__nor2_1 _688_ (
    .A(en),
    .B(\p[2] ),
    .Y(_372_)
  );
  sky130_fd_sc_hd__a21oi_1 _689_ (
    .A1(en),
    .A2(_371_),
    .B1(_372_),
    .Y(_009_)
  );
  sky130_fd_sc_hd__xnor2_1 _690_ (
    .A(_298_),
    .B(_299_),
    .Y(_373_)
  );
  sky130_fd_sc_hd__nor2_1 _691_ (
    .A(en),
    .B(\p[3] ),
    .Y(_374_)
  );
  sky130_fd_sc_hd__a21oi_1 _692_ (
    .A1(en),
    .A2(_373_),
    .B1(_374_),
    .Y(_008_)
  );
  sky130_fd_sc_hd__nor2_1 _693_ (
    .A(_300_),
    .B(_302_),
    .Y(_375_)
  );
  sky130_fd_sc_hd__nand2_1 _694_ (
    .A(en),
    .B(_303_),
    .Y(_376_)
  );
  sky130_fd_sc_hd__o2bb2ai_1 _695_ (
    .A1_N(_052_),
    .A2_N(\p[4] ),
    .B1(_375_),
    .B2(_376_),
    .Y(_007_)
  );
  sky130_fd_sc_hd__xor2_1 _696_ (
    .A(acc[5]),
    .B(\p[5] ),
    .X(_088_)
  );
  sky130_fd_sc_hd__nand2_1 _697_ (
    .A(_303_),
    .B(_304_),
    .Y(_377_)
  );
  sky130_fd_sc_hd__nand2_1 _698_ (
    .A(_305_),
    .B(_377_),
    .Y(_378_)
  );
  sky130_fd_sc_hd__nor2_1 _699_ (
    .A(en),
    .B(\p[5] ),
    .Y(_379_)
  );
  sky130_fd_sc_hd__a21oi_1 _700_ (
    .A1(en),
    .A2(_378_),
    .B1(_379_),
    .Y(_006_)
  );
  sky130_fd_sc_hd__nand3_1 _701_ (
    .A(_284_),
    .B(_294_),
    .C(_305_),
    .Y(_380_)
  );
  sky130_fd_sc_hd__a21oi_1 _702_ (
    .A1(_306_),
    .A2(_380_),
    .B1(_052_),
    .Y(_381_)
  );
  sky130_fd_sc_hd__nor2_1 _703_ (
    .A(en),
    .B(\p[6] ),
    .Y(_382_)
  );
  sky130_fd_sc_hd__nor2_1 _704_ (
    .A(_381_),
    .B(_382_),
    .Y(_005_)
  );
  sky130_fd_sc_hd__nor2_1 _705_ (
    .A(en),
    .B(\p[7] ),
    .Y(_383_)
  );
  sky130_fd_sc_hd__nand3_1 _706_ (
    .A(_266_),
    .B(_283_),
    .C(_306_),
    .Y(_384_)
  );
  sky130_fd_sc_hd__maj3_1 _707_ (
    .A(acc[5]),
    .B(\p[5] ),
    .C(_087_),
    .X(_089_)
  );
  sky130_fd_sc_hd__nand2b_1 _708_ (
    .A_N(_307_),
    .B(_384_),
    .Y(_385_)
  );
  sky130_fd_sc_hd__a21oi_1 _709_ (
    .A1(en),
    .A2(_385_),
    .B1(_383_),
    .Y(_004_)
  );
  sky130_fd_sc_hd__xor2_1 _710_ (
    .A(_265_),
    .B(_307_),
    .X(_386_)
  );
  sky130_fd_sc_hd__nor2_1 _711_ (
    .A(en),
    .B(\p[8] ),
    .Y(_387_)
  );
  sky130_fd_sc_hd__a21oi_1 _712_ (
    .A1(en),
    .A2(_386_),
    .B1(_387_),
    .Y(_003_)
  );
  sky130_fd_sc_hd__nand3_1 _713_ (
    .A(_264_),
    .B(_308_),
    .C(_309_),
    .Y(_388_)
  );
  sky130_fd_sc_hd__a21oi_1 _714_ (
    .A1(_310_),
    .A2(_388_),
    .B1(_052_),
    .Y(_389_)
  );
  sky130_fd_sc_hd__nor2_1 _715_ (
    .A(en),
    .B(\p[9] ),
    .Y(_390_)
  );
  sky130_fd_sc_hd__nor2_1 _716_ (
    .A(_389_),
    .B(_390_),
    .Y(_002_)
  );
  sky130_fd_sc_hd__xnor2_1 _717_ (
    .A(_311_),
    .B(_312_),
    .Y(_391_)
  );
  sky130_fd_sc_hd__nor2_1 _718_ (
    .A(acc[6]),
    .B(\p[6] ),
    .Y(_090_)
  );
  sky130_fd_sc_hd__nor2_1 _719_ (
    .A(en),
    .B(\p[10] ),
    .Y(_392_)
  );
  sky130_fd_sc_hd__a21oi_1 _720_ (
    .A1(en),
    .A2(_391_),
    .B1(_392_),
    .Y(_001_)
  );
  sky130_fd_sc_hd__nor3_1 _721_ (
    .A(_217_),
    .B(_313_),
    .C(_314_),
    .Y(_393_)
  );
  sky130_fd_sc_hd__nor3_1 _722_ (
    .A(_052_),
    .B(_315_),
    .C(_393_),
    .Y(_394_)
  );
  sky130_fd_sc_hd__a21o_1 _723_ (
    .A1(_052_),
    .A2(\p[11] ),
    .B1(_394_),
    .X(_000_)
  );
  sky130_fd_sc_hd__and2_0 _724_ (
    .A(\p[14] ),
    .B(acc[14]),
    .X(_055_)
  );
  sky130_fd_sc_hd__nor2_1 _725_ (
    .A(_077_),
    .B(_090_),
    .Y(_091_)
  );
  sky130_fd_sc_hd__a21o_1 _726_ (
    .A1(_089_),
    .A2(_091_),
    .B1(_077_),
    .X(_092_)
  );
  sky130_fd_sc_hd__a211oi_1 _727_ (
    .A1(_089_),
    .A2(_091_),
    .B1(_075_),
    .C1(_077_),
    .Y(_093_)
  );
  sky130_fd_sc_hd__nor2_1 _728_ (
    .A(_076_),
    .B(_093_),
    .Y(_094_)
  );
  sky130_fd_sc_hd__o31ai_1 _729_ (
    .A1(_073_),
    .A2(_076_),
    .A3(_093_),
    .B1(_072_),
    .Y(_095_)
  );
  sky130_fd_sc_hd__o21a_1 _730_ (
    .A1(_070_),
    .A2(_095_),
    .B1(_071_),
    .X(_096_)
  );
  sky130_fd_sc_hd__o211a_1 _731_ (
    .A1(_070_),
    .A2(_095_),
    .B1(_071_),
    .C1(_069_),
    .X(_097_)
  );
  sky130_fd_sc_hd__nor2_1 _732_ (
    .A(_067_),
    .B(_097_),
    .Y(_098_)
  );
  sky130_fd_sc_hd__a21oi_1 _733_ (
    .A1(_064_),
    .A2(_098_),
    .B1(_065_),
    .Y(_099_)
  );
  sky130_fd_sc_hd__o311ai_0 _734_ (
    .A1(_063_),
    .A2(_067_),
    .A3(_097_),
    .B1(_066_),
    .C1(_062_),
    .Y(_100_)
  );
  sky130_fd_sc_hd__nor2_1 _735_ (
    .A(\p[14] ),
    .B(acc[14]),
    .Y(_056_)
  );
  sky130_fd_sc_hd__a31oi_1 _736_ (
    .A1(_058_),
    .A2(_060_),
    .A3(_100_),
    .B1(_059_),
    .Y(_101_)
  );
  sky130_fd_sc_hd__a21oi_1 _737_ (
    .A1(_057_),
    .A2(_101_),
    .B1(_055_),
    .Y(_102_)
  );
  sky130_fd_sc_hd__o21ai_0 _738_ (
    .A1(\p[15] ),
    .A2(acc[15]),
    .B1(en),
    .Y(_103_)
  );
  sky130_fd_sc_hd__a21oi_1 _739_ (
    .A1(_054_),
    .A2(_102_),
    .B1(_103_),
    .Y(_104_)
  );
  sky130_fd_sc_hd__a211oi_1 _740_ (
    .A1(_054_),
    .A2(_102_),
    .B1(_103_),
    .C1(_053_),
    .Y(_105_)
  );
  sky130_fd_sc_hd__nand2_1 _741_ (
    .A(acc[17]),
    .B(_105_),
    .Y(_106_)
  );
  sky130_fd_sc_hd__nand3_1 _742_ (
    .A(acc[18]),
    .B(acc[17]),
    .C(_105_),
    .Y(_107_)
  );
  sky130_fd_sc_hd__xnor2_1 _743_ (
    .A(acc[18]),
    .B(_106_),
    .Y(_050_)
  );
  sky130_fd_sc_hd__xnor2_1 _744_ (
    .A(_085_),
    .B(_086_),
    .Y(_108_)
  );
  sky130_fd_sc_hd__nor2_1 _745_ (
    .A(en),
    .B(acc[4]),
    .Y(_109_)
  );
  sky130_fd_sc_hd__nor2_1 _746_ (
    .A(_055_),
    .B(_056_),
    .Y(_057_)
  );
  sky130_fd_sc_hd__a21oi_1 _747_ (
    .A1(en),
    .A2(_108_),
    .B1(_109_),
    .Y(_049_)
  );
  sky130_fd_sc_hd__xnor2_1 _748_ (
    .A(acc[19]),
    .B(_107_),
    .Y(_048_)
  );
  sky130_fd_sc_hd__nor2_1 _749_ (
    .A(en),
    .B(\p[15] ),
    .Y(_110_)
  );
  sky130_fd_sc_hd__nand2_1 _750_ (
    .A(\rb[7] ),
    .B(\ra[4] ),
    .Y(_111_)
  );
  sky130_fd_sc_hd__nand2_1 _751_ (
    .A(\ra[6] ),
    .B(\rb[3] ),
    .Y(_112_)
  );
  sky130_fd_sc_hd__nand2_1 _752_ (
    .A(\ra[6] ),
    .B(\rb[4] ),
    .Y(_113_)
  );
  sky130_fd_sc_hd__nand2_1 _753_ (
    .A(\ra[7] ),
    .B(\rb[3] ),
    .Y(_114_)
  );
  sky130_fd_sc_hd__nand2_1 _754_ (
    .A(\ra[5] ),
    .B(\rb[5] ),
    .Y(_115_)
  );
  sky130_fd_sc_hd__xnor2_1 _755_ (
    .A(_113_),
    .B(_114_),
    .Y(_116_)
  );
  sky130_fd_sc_hd__maj3_1 _756_ (
    .A(_113_),
    .B(_114_),
    .C(_115_),
    .X(_117_)
  );
  sky130_fd_sc_hd__nand2_1 _757_ (
    .A(acc[13]),
    .B(\p[13] ),
    .Y(_058_)
  );
  sky130_fd_sc_hd__nand2_1 _758_ (
    .A(\ra[5] ),
    .B(\rb[6] ),
    .Y(_118_)
  );
  sky130_fd_sc_hd__xnor2_1 _759_ (
    .A(_117_),
    .B(_118_),
    .Y(_119_)
  );
  sky130_fd_sc_hd__xnor2_1 _760_ (
    .A(_111_),
    .B(_119_),
    .Y(_120_)
  );
  sky130_fd_sc_hd__nand2_1 _761_ (
    .A(\ra[7] ),
    .B(\rb[5] ),
    .Y(_121_)
  );
  sky130_fd_sc_hd__nor2_1 _762_ (
    .A(_113_),
    .B(_121_),
    .Y(_122_)
  );
  sky130_fd_sc_hd__a22oi_1 _763_ (
    .A1(\ra[7] ),
    .A2(\rb[4] ),
    .B1(\rb[5] ),
    .B2(\ra[6] ),
    .Y(_123_)
  );
  sky130_fd_sc_hd__nor2_1 _764_ (
    .A(_122_),
    .B(_123_),
    .Y(_124_)
  );
  sky130_fd_sc_hd__nand2b_1 _765_ (
    .A_N(_120_),
    .B(_124_),
    .Y(_125_)
  );
  sky130_fd_sc_hd__nand2_1 _766_ (
    .A(\rb[7] ),
    .B(\ra[5] ),
    .Y(_126_)
  );
  sky130_fd_sc_hd__nand2_1 _767_ (
    .A(\ra[6] ),
    .B(\rb[6] ),
    .Y(_127_)
  );
  sky130_fd_sc_hd__nor2_1 _768_ (
    .A(acc[13]),
    .B(\p[13] ),
    .Y(_059_)
  );
  sky130_fd_sc_hd__clkinv_1 _769_ (
    .A(_127_),
    .Y(_128_)
  );
  sky130_fd_sc_hd__nor2_1 _770_ (
    .A(_122_),
    .B(_128_),
    .Y(_129_)
  );
  sky130_fd_sc_hd__nand2_1 _771_ (
    .A(\rb[6] ),
    .B(_122_),
    .Y(_130_)
  );
  sky130_fd_sc_hd__a21oi_1 _772_ (
    .A1(\rb[6] ),
    .A2(_122_),
    .B1(_129_),
    .Y(_131_)
  );
  sky130_fd_sc_hd__xnor2_1 _773_ (
    .A(_126_),
    .B(_131_),
    .Y(_132_)
  );
  sky130_fd_sc_hd__nor2b_1 _774_ (
    .A(_121_),
    .B_N(_132_),
    .Y(_133_)
  );
  sky130_fd_sc_hd__xor2_1 _775_ (
    .A(_121_),
    .B(_132_),
    .X(_134_)
  );
  sky130_fd_sc_hd__maj3_1 _776_ (
    .A(_111_),
    .B(_117_),
    .C(_118_),
    .X(_135_)
  );
  sky130_fd_sc_hd__xnor2_1 _777_ (
    .A(_125_),
    .B(_134_),
    .Y(_136_)
  );
  sky130_fd_sc_hd__maj3_1 _778_ (
    .A(_125_),
    .B(_134_),
    .C(_135_),
    .X(_137_)
  );
  sky130_fd_sc_hd__nand2_1 _779_ (
    .A(acc[12]),
    .B(\p[12] ),
    .Y(_060_)
  );
  sky130_fd_sc_hd__o21ai_0 _780_ (
    .A1(_126_),
    .A2(_129_),
    .B1(_130_),
    .Y(_138_)
  );
  sky130_fd_sc_hd__a22oi_1 _781_ (
    .A1(\rb[7] ),
    .A2(\ra[6] ),
    .B1(\rb[6] ),
    .B2(\ra[7] ),
    .Y(_139_)
  );
  sky130_fd_sc_hd__a31oi_1 _782_ (
    .A1(\ra[7] ),
    .A2(\rb[7] ),
    .A3(_128_),
    .B1(_139_),
    .Y(_140_)
  );
  sky130_fd_sc_hd__xnor2_1 _783_ (
    .A(_133_),
    .B(_140_),
    .Y(_141_)
  );
  sky130_fd_sc_hd__xor2_1 _784_ (
    .A(_138_),
    .B(_141_),
    .X(_142_)
  );
  sky130_fd_sc_hd__or2_0 _785_ (
    .A(_137_),
    .B(_142_),
    .X(_143_)
  );
  sky130_fd_sc_hd__nand2_1 _786_ (
    .A(\ra[6] ),
    .B(\rb[1] ),
    .Y(_144_)
  );
  sky130_fd_sc_hd__nand2_1 _787_ (
    .A(\ra[4] ),
    .B(\rb[5] ),
    .Y(_145_)
  );
  sky130_fd_sc_hd__nand2_1 _788_ (
    .A(\ra[5] ),
    .B(\rb[4] ),
    .Y(_146_)
  );
  sky130_fd_sc_hd__nand2_1 _789_ (
    .A(\ra[5] ),
    .B(\rb[3] ),
    .Y(_147_)
  );
  sky130_fd_sc_hd__dfrtp_1 _790_ (
    .CLK(clk),
    .D(_012_),
    .Q(\rb[6] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _791_ (
    .CLK(clk),
    .D(_046_),
    .Q(\rb[7] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _792_ (
    .CLK(clk),
    .D(_011_),
    .Q(\p[0] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _793_ (
    .CLK(clk),
    .D(_010_),
    .Q(\p[1] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _794_ (
    .CLK(clk),
    .D(_009_),
    .Q(\p[2] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _795_ (
    .CLK(clk),
    .D(_008_),
    .Q(\p[3] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _796_ (
    .CLK(clk),
    .D(_007_),
    .Q(\p[4] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _797_ (
    .CLK(clk),
    .D(_006_),
    .Q(\p[5] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _798_ (
    .CLK(clk),
    .D(_005_),
    .Q(\p[6] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _799_ (
    .CLK(clk),
    .D(_004_),
    .Q(\p[7] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _800_ (
    .CLK(clk),
    .D(_003_),
    .Q(\p[8] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _801_ (
    .CLK(clk),
    .D(_002_),
    .Q(\p[9] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _802_ (
    .CLK(clk),
    .D(_001_),
    .Q(\p[10] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _803_ (
    .CLK(clk),
    .D(_000_),
    .Q(\p[11] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _804_ (
    .CLK(clk),
    .D(_023_),
    .Q(\p[12] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _805_ (
    .CLK(clk),
    .D(_027_),
    .Q(\p[13] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _806_ (
    .CLK(clk),
    .D(_032_),
    .Q(\p[14] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _807_ (
    .CLK(clk),
    .D(_047_),
    .Q(\p[15] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _808_ (
    .CLK(clk),
    .D(_025_),
    .Q(acc[0]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _809_ (
    .CLK(clk),
    .D(_028_),
    .Q(acc[1]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _810_ (
    .CLK(clk),
    .D(_019_),
    .Q(acc[2]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _811_ (
    .CLK(clk),
    .D(_026_),
    .Q(acc[3]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _812_ (
    .CLK(clk),
    .D(_049_),
    .Q(acc[4]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _813_ (
    .CLK(clk),
    .D(_024_),
    .Q(acc[5]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _814_ (
    .CLK(clk),
    .D(_034_),
    .Q(acc[6]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _815_ (
    .CLK(clk),
    .D(_022_),
    .Q(acc[7]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _816_ (
    .CLK(clk),
    .D(_036_),
    .Q(acc[8]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _817_ (
    .CLK(clk),
    .D(_021_),
    .Q(acc[9]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _818_ (
    .CLK(clk),
    .D(_037_),
    .Q(acc[10]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _819_ (
    .CLK(clk),
    .D(_033_),
    .Q(acc[11]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _820_ (
    .CLK(clk),
    .D(_038_),
    .Q(acc[12]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _821_ (
    .CLK(clk),
    .D(_029_),
    .Q(acc[13]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _822_ (
    .CLK(clk),
    .D(_031_),
    .Q(acc[14]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _823_ (
    .CLK(clk),
    .D(_035_),
    .Q(acc[15]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _824_ (
    .CLK(clk),
    .D(_030_),
    .Q(acc[16]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _825_ (
    .CLK(clk),
    .D(_020_),
    .Q(acc[17]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _826_ (
    .CLK(clk),
    .D(_050_),
    .Q(acc[18]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _827_ (
    .CLK(clk),
    .D(_048_),
    .Q(acc[19]),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _828_ (
    .CLK(clk),
    .D(_045_),
    .Q(\ra[0] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _829_ (
    .CLK(clk),
    .D(_044_),
    .Q(\ra[1] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _830_ (
    .CLK(clk),
    .D(_043_),
    .Q(\ra[2] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _831_ (
    .CLK(clk),
    .D(_042_),
    .Q(\ra[3] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _832_ (
    .CLK(clk),
    .D(_041_),
    .Q(\ra[4] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _833_ (
    .CLK(clk),
    .D(_040_),
    .Q(\ra[5] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _834_ (
    .CLK(clk),
    .D(_039_),
    .Q(\ra[6] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _835_ (
    .CLK(clk),
    .D(_051_),
    .Q(\ra[7] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _836_ (
    .CLK(clk),
    .D(_018_),
    .Q(\rb[0] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _837_ (
    .CLK(clk),
    .D(_017_),
    .Q(\rb[1] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _838_ (
    .CLK(clk),
    .D(_016_),
    .Q(\rb[2] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _839_ (
    .CLK(clk),
    .D(_015_),
    .Q(\rb[3] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _840_ (
    .CLK(clk),
    .D(_014_),
    .Q(\rb[4] ),
    .RESET_B(rst_n)
  );
  sky130_fd_sc_hd__dfrtp_1 _841_ (
    .CLK(clk),
    .D(_013_),
    .Q(\rb[5] ),
    .RESET_B(rst_n)
  );
endmodule

Check yourself

Predict the outputBefore placement the MAC's worst setup slack is 0.3041 ns at a 4.6 ns clock. What WNS does STA report on the same netlist at 4.4 ns, in ns?
create_clock -name clk -period 4.4 [get_ports clk]
ConceptMet1 is estimated at 0.172375 fF per µm. What capacitance does a 50 µm met1 net add?
ConceptWhy does a short net's capacitance cost more delay than its resistance in this technology?
ConceptA path has one high-fanout net. Which move directly increases the critical net's off-path pin load, assuming a larger input capacitance?
Conceptrepair_timing has run out of moves and the path still fails by 0.3 ns. What is the next step?

Remember

  • After placement, estimate_parasitics -placement gives every net a Steiner-tree wire with resistance and capacitance per µm.
  • On short nets the wire's capacitance, charged by the driving cell, costs far more delay than the wire's own RC delay.
  • Timing-driven placement re-weights the nets on critical paths during placement; repair_timing -setup resizes, buffers, swaps pins and clones on the placed design.
  • Legalization moves cells, so slack is re-checked after it; hold waits for the clock tree, and a path the tools cannot fix goes back to the RTL.