Add interrupts module: INT 3 (CC breakpoint) vs INT 21h (DOS services)

NASM sources, DOSBox/FreeDOS Debug/Unicorn harness, captured output and 31 assertions backing the ankurm.com article "INT 3 vs INT 21h in 8086 Assembly". Co-Authored-By: Claude Sonnet 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01KqJyCidz3ZgRyHABv2GVJh
2026-09-30 19:10:56 +00:00
commit 09af523f8c
27 changed files with 1029 additions and 0 deletions
@@ -0,0 +1,13 @@
+; bp_target.asm -- a flat 16-bit routine used by the Unicorn breakpoint experiment.
+; Three one-byte INC CX instructions, so a two-byte CD 03 patch on the first one
+; overwrites the first byte of the second one too.
+bits 16
+org 0x7C00
+start:
+    xor cx, cx
+site:
+    inc cx                  ; 41   <- breakpoint goes here
+    inc cx                  ; 41
+    inc cx                  ; 41
+done:
+    nop