diff --git a/gds/caravel_0001000a.gds.gz b/gds/caravel_0001000a.gds.gz
index 9722443..4137b64 100644
--- a/gds/caravel_0001000a.gds.gz
+++ b/gds/caravel_0001000a.gds.gz
Binary files differ
diff --git a/signoff/caravel_fix b/signoff/caravel_fix
new file mode 100644
index 0000000..fb82284
--- /dev/null
+++ b/signoff/caravel_fix
@@ -0,0 +1 @@
+f0b5406c69f010ed933329ebf5e5afea113746d2  ./gds/caravel_0001000a_b.gds
diff --git a/signoff/caravel_fix_xor.out b/signoff/caravel_fix_xor.out
new file mode 100644
index 0000000..2749217
--- /dev/null
+++ b/signoff/caravel_fix_xor.out
@@ -0,0 +1,1238 @@
+First Layout: ./gds/caravel_0001000a.gds
+Second Layout: ./gds/caravel_0001000a_b.gds
+Design Name: caravel_0001000a
+Output GDS will be: ./gds/caravel_0001000a_fix_xor.gds
+Reading ./gds/caravel_0001000a.gds ..
+Reading ./gds/caravel_0001000a_b.gds ..
+--- Running XOR for 105/52 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 107/24 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 11/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 112/4 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 122/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 2.700s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 125/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 125/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.110s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 20/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 21/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 22/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 22/21 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 8.150s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 22/22 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 2.770s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 22/24 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 23/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 23/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 2.440s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 235/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 4.870s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 235/4 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 26.140s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 236/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 2.650s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 25/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 27/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 28/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 28/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 19.450s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 30/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 32/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 33/42 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 43.780s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 33/43 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 43.880s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 34/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 34/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 23.200s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 35/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 36/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 36/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 34.830s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 37/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 39/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 40/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 41/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 41/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 48.280s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 43/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 44/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 46/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 48/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 49/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 50/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 51/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 51/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 22.570s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 56/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 56/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 6.900s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 58/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 59/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 59/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 1.400s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 61/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 62/24 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 64/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 2.680s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 64/18 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.020s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 64/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 10.470s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 64/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 1.040s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 64/59 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 1.040s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 65/13 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 65/14 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 65/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.830s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 65/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 16.930s
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+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 65/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 3.990s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 66/13 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.050s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 66/14 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.030s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 66/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.230s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 66/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 1.070s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 66/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 35.600s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 66/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 78.060s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 66/83 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 1.610s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 66/9 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 67/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 67/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 5.660s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 67/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 69.020s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 67/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 57.070s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 67/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.830s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 68/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.080s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 68/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 10.050s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 68/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 110.930s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 68/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 14.420s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 68/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 1.380s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 69/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.040s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 69/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 3.480s
+XOR differences: 4
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 69/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 38.570s
+XOR differences: 2
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 69/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 5.660s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 69/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.270s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 70/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 70/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.980s
+XOR differences: 1
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 70/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 19.100s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 70/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 17.230s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 70/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.240s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 71/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 71/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.870s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 71/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 19.640s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 71/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 1.610s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 71/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.370s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 72/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 72/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.020s
+XOR differences: 58
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 72/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.460s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 72/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.300s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 75/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 1.560s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 76/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 78/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 4.960s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 79/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 81/1 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 81/14 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.200s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 81/19 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.020s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 81/2 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 2.070s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 81/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 81/23 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.390s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 81/4 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 26.840s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 81/51 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 81/52 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 81/6 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.030s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 81/8 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.020s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 83/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 3.320s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 88/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 89/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 93/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 13.460s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 94/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 11.450s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 95/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 8.200s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 96/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 97/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 97/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 98/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+Writing layout file: ./gds/caravel_0001000a_fix_xor.gds ..
+Total run time: 916.730s
diff --git a/signoff/run_metal_fix.out b/signoff/run_metal_fix.out
new file mode 100644
index 0000000..723aad1
--- /dev/null
+++ b/signoff/run_metal_fix.out
@@ -0,0 +1,65 @@
+Finding the prefix used for caravel subcells in the user GDS.
+User prefix is i4_
+Replacing cell caravel in the user GDS file.
+Reading GDS file for alternate cell caravel
+Cell caravel found at position 235669746
+Cell caravel ends at position 247680056
+Reading GDS file for original source ./gds/caravel_0001000a.gds
+Cell caravel found at position 2094878850
+Cell caravel ends at position 2106888702
+Cell caravel checksum is 12009824
+Info:  Structure caravel matches checksum 12009824
+Info:  Structure caravel at 2094878850 to 2106888702 will be replaced by alternate data.
+Prefixing caravel subcells in the user GDS
+Running:  /usr/share/pdk/bin/change_gds_string.py user_id_textblock i4_user_id_textblock copyright_block i4_copyright_block open_source i4_open_source storage i4_storage sky130_fd_sc_hvl__lsbufhv2lv_1_wrapped i4_sky130_fd_sc_hvl__lsbufhv2lv_1_wrapped user_id_programming i4_user_id_programming simple_por i4_simple_por gpio_control_block i4_gpio_control_block mgmt_core i4_mgmt_core mgmt_protect i4_mgmt_protect chip_io i4_chip_io user_project_wrapper i4_user_project_wrapper ./gds/caravel_0001000a_b.gds -debug -verbatim
+Original data length = 2106889424
+Replaced b'open_source\x00' with b'i4_open_source'
+Replaced b'user_id_textblock\x00' with b'i4_user_id_textblock'
+Replaced b'copyright_block\x00' with b'i4_copyright_block'
+Replaced b'storage\x00' with b'i4_storage'
+Replaced b'sky130_fd_sc_hvl__lsbufhv2lv_1_wrapped' with b'i4_sky130_fd_sc_hvl__lsbufhv2lv_1_wrapped\x00'
+Replaced b'user_id_programming\x00' with b'i4_user_id_programming'
+Replaced b'simple_por' with b'i4_simple_por\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'mgmt_core\x00' with b'i4_mgmt_core'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'mgmt_protect' with b'i4_mgmt_protect\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'gpio_control_block' with b'i4_gpio_control_block\x00'
+Replaced b'chip_io\x00' with b'i4_chip_io'
+Replaced b'user_project_wrapper' with b'i4_user_project_wrapper\x00'
+Finished.