diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ce7c0f8..d8aa6d5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,16 +55,17 @@ jobs:
     - name: Generate debug asm files
       if: strategy.job-index == 0
       run: |
-        objdump -d -x src/copapy/obj/stencils_x86_64_O3.o > bin/stencils_x86_64_O3.asm
-        echo '<p>stencils_x86_64_O3.asm</p><pre>' >> $GITHUB_STEP_SUMMARY
-        cat bin/stencils_x86_64_O3.asm >> $GITHUB_STEP_SUMMARY
-        echo '</pre>' >> $GITHUB_STEP_SUMMARY
-        python tools/make_example.py
+        pip install ansi2html
         python tools/extract_code.py "bin/test.copapy" "bin/test.copapy.bin"
-        objdump -D -b binary -m i386:x86-64 --adjust-vma=0x1000 bin/test.copapy.bin > bin/test.copapy.asm
-        echo '<p>test.copapy.asm</p><pre>' >> $GITHUB_STEP_SUMMARY
-        cat bin/test.copapy.asm >> $GITHUB_STEP_SUMMARY
-        echo '</pre>' >> $GITHUB_STEP_SUMMARY
+        objdump --color=always -D -b binary -m i386:x86-64 --adjust-vma=0x1000 bin/test.copapy.bin > bin/test.copapy.asm
+        echo '<p>test.copapy.asm</p><code>' >> $GITHUB_STEP_SUMMARY
+        cat bin/test.copapy.asm | ansi2html >> $GITHUB_STEP_SUMMARY
+        echo '</code>' >> $GITHUB_STEP_SUMMARY
+        objdump --color=always -d -j .text src/copapy/obj/stencils_x86_64_O3.o > bin/stencils_x86_64_O3.asm
+        echo '<p>stencils_x86_64_O3.asm</p><code>' >> $GITHUB_STEP_SUMMARY
+        cat bin/stencils_x86_64_O3.asm | ansi2html >> $GITHUB_STEP_SUMMARY
+        echo '</code>' >> $GITHUB_STEP_SUMMARY
+        python tools/make_example.py
 
     - name: Run tests with pytest
       run: pytest
diff --git a/tools/generate_stencils.py b/tools/generate_stencils.py
index 6dbb6e2..e88c5f6 100644
--- a/tools/generate_stencils.py
+++ b/tools/generate_stencils.py
@@ -7,10 +7,13 @@ op_signs = {'add': '+', 'sub': '-', 'mul': '*', 'div': '/',
 entry_func_prefix = ''
 stencil_func_prefix = '__attribute__((naked)) '  # Remove callee prolog
 
+stack_size = 64
+
 def get_aux_funcs() -> str:
     return f"""
     {entry_func_prefix}int entry_function_shell(){{
-        volatile char stack_place_holder[64];
+        volatile char stack_place_holder[{stack_size}];
+        stack_place_holder[0] = 0;
         result_int(0);
         return 1;
     }}