diff --git a/gds/caravel_0001000d.gds.gz b/gds/caravel_0001000d.gds.gz
index 17846bc..93dbdda 100644
--- a/gds/caravel_0001000d.gds.gz
+++ b/gds/caravel_0001000d.gds.gz
Binary files differ
diff --git a/gds/caravel_0001000d_b.gds.gz b/gds/caravel_0001000d_b.gds.gz
new file mode 100644
index 0000000..51a5b39
--- /dev/null
+++ b/gds/caravel_0001000d_b.gds.gz
Binary files differ
diff --git a/signoff/caravel_fix b/signoff/caravel_fix
new file mode 100644
index 0000000..6941724
--- /dev/null
+++ b/signoff/caravel_fix
@@ -0,0 +1 @@
+80d10f072a90c2bed20ec1033ec7d5281f3f34e9  ./gds/caravel_0001000d_b.gds
diff --git a/signoff/caravel_fix_xor.out b/signoff/caravel_fix_xor.out
new file mode 100644
index 0000000..accecfd
--- /dev/null
+++ b/signoff/caravel_fix_xor.out
@@ -0,0 +1,1238 @@
+First Layout: ./gds/caravel_0001000d.gds
+Second Layout: ./gds/caravel_0001000d_b.gds
+Design Name: caravel_0001000d
+Output GDS will be: ./gds/caravel_0001000d_fix_xor.gds
+Reading ./gds/caravel_0001000d.gds ..
+Reading ./gds/caravel_0001000d_b.gds ..
+--- Running XOR for 105/52 ---
+"_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: 10
+"_output" in: xor.drc:41
+Elapsed: 0.020s
+--- Running XOR for 107/24 ---
+"_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: 10
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 11/0 ---
+"_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 112/4 ---
+"_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: 10
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 122/16 ---
+"_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: 281867
+"_output" in: xor.drc:41
+Elapsed: 0.240s
+--- 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: 109
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 125/44 ---
+"_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: 5945
+"_output" in: xor.drc:41
+Elapsed: 0.020s
+--- Running XOR for 20/0 ---
+"_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 21/0 ---
+"_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 22/0 ---
+"_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 22/21 ---
+"_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: 238680
+"_output" in: xor.drc:41
+Elapsed: 0.080s
+--- Running XOR for 22/22 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.330s
+XOR differences: 68640
+"_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: 4
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 23/0 ---
+"_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 23/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 2.460s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 235/0 ---
+"_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: 102960
+"_output" in: xor.drc:41
+Elapsed: 0.060s
+--- Running XOR for 235/4 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 2.670s
+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: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 233833
+"_output" in: xor.drc:41
+Elapsed: 0.200s
+--- 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: 20.380s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- 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: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 32/0 ---
+"_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 33/42 ---
+"_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: 823680
+"_output" in: xor.drc:41
+Elapsed: 0.350s
+--- Running XOR for 33/43 ---
+"_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: 1020240
+"_output" in: xor.drc:41
+Elapsed: 0.310s
+--- 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: 28.960s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- 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: 69.980s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 37/0 ---
+"_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 39/0 ---
+"_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 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: 58.570s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 43/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
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+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 44/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
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+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 46/0 ---
+"_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 48/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
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+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 49/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
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+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 50/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 51/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 51/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 23.550s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 56/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 56/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 6.580s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 58/0 ---
+"_input" in: xor.drc:38
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+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: 0.010s
+"^" in: xor.drc:38
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+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 59/28 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 1.420s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 61/20 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 62/24 ---
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+"_output" in: xor.drc:41
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+--- Running XOR for 64/16 ---
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+"^" in: xor.drc:38
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+XOR differences: 281867
+"_output" in: xor.drc:41
+Elapsed: 0.230s
+--- Running XOR for 64/18 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 533
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 64/20 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.370s
+--- Running XOR for 64/5 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.330s
+--- Running XOR for 64/59 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+"_output" in: xor.drc:41
+Elapsed: 0.330s
+--- Running XOR for 65/13 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+XOR differences: 109
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 65/14 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+XOR differences: 75
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 65/16 ---
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+Elapsed: 0.010s
+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.030s
+--- Running XOR for 65/20 ---
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
+Elapsed: 6.120s
+XOR differences: 601229
+"_output" in: xor.drc:41
+Elapsed: 0.100s
+--- Running XOR for 65/44 ---
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+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
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+XOR differences: 146099
+"_output" in: xor.drc:41
+Elapsed: 0.190s
+--- Running XOR for 66/13 ---
+"_input" in: xor.drc:38
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+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
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+XOR differences: 3279
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 66/14 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
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+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 1900
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 66/15 ---
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+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
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+XOR differences: 1536
+"_output" in: xor.drc:41
+Elapsed: 0.040s
+--- Running XOR for 66/16 ---
+"_input" in: xor.drc:38
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+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.050s
+--- 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: 0.010s
+XOR differences: 1338180
+"_output" in: xor.drc:41
+Elapsed: 1.020s
+--- 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: 0.000s
+XOR differences: 8114439
+"_output" in: xor.drc:41
+Elapsed: 1.810s
+--- 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: 0.010s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.190s
+--- 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: 92
+"_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: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 182
+"_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: 0.000s
+XOR differences: 737028
+"_output" in: xor.drc:41
+Elapsed: 0.270s
+--- 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: 0.010s
+XOR differences: 2575185
+"_output" in: xor.drc:41
+Elapsed: 1.560s
+--- Running XOR for 67/44 ---
+"_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: 6699294
+"_output" in: xor.drc:41
+Elapsed: 1.490s
+--- Running XOR for 67/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 0
+"_output" in: xor.drc:41
+Elapsed: 0.440s
+--- Running XOR for 68/15 ---
+"_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: 6122
+"_output" in: xor.drc:41
+Elapsed: 0.020s
+--- 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
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+XOR differences: 758798
+"_output" in: xor.drc:41
+Elapsed: 0.440s
+--- Running XOR for 68/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 20.750s
+XOR differences: 387506
+"_output" in: xor.drc:41
+Elapsed: 0.070s
+--- Running XOR for 68/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 5.490s
+XOR differences: 1402793
+"_output" in: xor.drc:41
+Elapsed: 0.240s
+--- Running XOR for 68/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 45
+"_output" in: xor.drc:41
+Elapsed: 0.670s
+--- Running XOR for 69/15 ---
+"_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: 3510
+"_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: 0.440s
+XOR differences: 70129
+"_output" in: xor.drc:41
+Elapsed: 0.020s
+--- 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: 11.660s
+XOR differences: 219892
+"_output" in: xor.drc:41
+Elapsed: 0.040s
+--- 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: 3.260s
+XOR differences: 937156
+"_output" in: xor.drc:41
+Elapsed: 0.140s
+--- Running XOR for 69/5 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
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+XOR differences: 5751
+"_output" in: xor.drc:41
+Elapsed: 0.150s
+--- Running XOR for 70/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
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+XOR differences: 88
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 70/16 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.100s
+XOR differences: 342
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- 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: 2.600s
+XOR differences: 62028
+"_output" in: xor.drc:41
+Elapsed: 0.020s
+--- 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: 4.790s
+XOR differences: 1116714
+"_output" in: xor.drc:41
+Elapsed: 0.200s
+--- 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: 0.010s
+XOR differences: 1943
+"_output" in: xor.drc:41
+Elapsed: 0.130s
+--- Running XOR for 71/15 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 88
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 71/16 ---
+"_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: 8726
+"_output" in: xor.drc:41
+Elapsed: 0.030s
+--- 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: 2.510s
+XOR differences: 4948
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 71/44 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 1.030s
+XOR differences: 186763
+"_output" in: xor.drc:41
+Elapsed: 0.040s
+--- 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: 0.000s
+XOR differences: 25722
+"_output" in: xor.drc:41
+Elapsed: 0.080s
+--- Running XOR for 72/15 ---
+"_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: 18
+"_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: 0.010s
+XOR differences: 1805
+"_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: 0.200s
+XOR differences: 923
+"_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: 0.010s
+XOR differences: 21658
+"_output" in: xor.drc:41
+Elapsed: 0.050s
+--- Running XOR for 75/20 ---
+"_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: 53374
+"_output" in: xor.drc:41
+Elapsed: 0.070s
+--- Running XOR for 76/20 ---
+"_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: 107
+"_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: 0.010s
+XOR differences: 319996
+"_output" in: xor.drc:41
+Elapsed: 0.290s
+--- 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: 1
+"_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: 0.010s
+--- Running XOR for 81/14 ---
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"_input" in: xor.drc:38
+Elapsed: 0.000s
+"^" in: xor.drc:38
+Elapsed: 0.100s
+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: 0.000s
+XOR differences: 981
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- 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: 0.000s
+XOR differences: 17680
+"_output" in: xor.drc:41
+Elapsed: 0.050s
+--- Running XOR for 81/20 ---
+"_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: 107
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 81/23 ---
+"_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: 24060
+"_output" in: xor.drc:41
+Elapsed: 0.050s
+--- Running XOR for 81/4 ---
+"_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: 668900
+"_output" in: xor.drc:41
+Elapsed: 0.530s
+--- 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: 0.010s
+"_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 81/6 ---
+"_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: 3799
+"_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: 0.000s
+XOR differences: 2520
+"_output" in: xor.drc:41
+Elapsed: 0.010s
+--- Running XOR for 83/44 ---
+"_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: 48
+"_output" in: xor.drc:41
+Elapsed: 0.710s
+--- Running XOR for 88/0 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_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 89/44 ---
+"_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: 1
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 93/44 ---
+"_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: 574760
+"_output" in: xor.drc:41
+Elapsed: 0.430s
+--- Running XOR for 94/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 513318
+"_output" in: xor.drc:41
+Elapsed: 0.400s
+--- Running XOR for 95/20 ---
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"_input" in: xor.drc:38
+Elapsed: 0.010s
+"^" in: xor.drc:38
+Elapsed: 0.000s
+XOR differences: 361396
+"_output" in: xor.drc:41
+Elapsed: 0.360s
+--- Running XOR for 96/0 ---
+"_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 97/0 ---
+"_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 97/44 ---
+"_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: 1
+"_output" in: xor.drc:41
+Elapsed: 0.000s
+--- Running XOR for 98/0 ---
+"_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
+Writing layout file: ./gds/caravel_0001000d_fix_xor.gds ..
+Total run time: 339.720s
diff --git a/signoff/run_metal_fix.out b/signoff/run_metal_fix.out
new file mode 100644
index 0000000..63f0e6e
--- /dev/null
+++ b/signoff/run_metal_fix.out
@@ -0,0 +1,20 @@
+Finding the prefix used for caravel subcells in the user GDS.
+User prefix is vB_
+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_0001000d.gds
+Cell caravel found at position 2703792626
+Cell caravel ends at position 2715802478
+Cell caravel checksum is 12009824
+Info:  Structure caravel matches checksum 12009824
+Info:  Structure caravel at 2703792626 to 2715802478 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 vB_user_id_textblock copyright_block vB_copyright_block open_source vB_open_source storage vB_storage sky130_fd_sc_hvl__lsbufhv2lv_1_wrapped vB_sky130_fd_sc_hvl__lsbufhv2lv_1_wrapped user_id_programming vB_user_id_programming simple_por vB_simple_por gpio_control_block vB_gpio_control_block mgmt_core vB_mgmt_core mgmt_protect vB_mgmt_protect chip_io vB_chip_io user_project_wrapper vB_user_project_wrapper ./gds/caravel_0001000d_b.gds -debug -verbatim
+Original data length = 2715803200
+Traceback (most recent call last):
+  File "/usr/share/pdk/bin/change_gds_string.py", line 122, in <module>
+    before = gdsdata[0:dataptr]
+MemoryError
+Finished.