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 +1,15 @@
+AH=30h DOS version          : 5.0
+AH=2Ah/2Ch date+time ranges : ok ok
+AH=02h + AH=06h             : AB
+AH=01h + AH=0Ah (stdin)     : echo -> Ankur
+
+                              AH=01h got 0x5A ; AH=0Ah count = 5, text = Ankur
+AH=25h/35h vector 60h       : ok
+AH=48h/49h alloc+free 4 KB  : ok
+AH=48h ask for 1 MB (fails)  : CF=1 AX=0008 ; largest block (paragraphs) = 8E6C
+AH=3Ch/40h/3Dh/3Fh/42h      : 12 bytes read ; LSEEK(end) says size = 12
+AH=56h + AH=4Eh findfirst   : U.TXT size = 12
+AH=41h delete, reopen fails : CF=1 AX=0002
+AH=39h/3Ah mkdir+rmdir      : ok ; AH=19h drive = 2
+AH=4Bh exec child           : Hello from INT 21h, AH=09h
+AH=4Dh return code = 7 type = 0