data segment a db 2Ah b db 13h c dw ? data ends code segment assume cs:code,ds:data start: mov ax,data mov ds,ax mov al,a mov bl,b sub al,bl mov c,ax int 3 code ends end start
Output
C:\TASM>masm an8sub.asm Microsoft (R) Macro Assembler Version 5.00 Copyright (C) Microsoft Corp 1981-1985, 1987. All rights reserved. Object filename [an8sub.OBJ]: Source listing [NUL.LST]: Cross-reference [NUL.CRF]: 50402 + 450254 Bytes symbol space free 0 Warning Errors 0 Severe Errors C:\TASM>link an8sub.obj Microsoft (R) Overlay Linker Version 3.60 Copyright (C) Microsoft Corp 1983-1987. All rights reserved. Run File [AN8SUB.EXE]: List File [NUL.MAP]: Libraries [.LIB]: LINK : warning L4021: no stack segment C:\TASM>debug an8sub.exe -g AX=0B17 BX=0013 CX=0022 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=0B97 ES=0B87 SS=0B97 CS=0B98 IP=0011 NV UP EI PL NZ NA PE NC 0B98:0011 CC INT 3 -d 0B97:0000 0B97:0000 2A 13 17 0B 00 00 00 00-00 00 00 00 00 00 00 00 *............... 0B97:0010 B8 97 0B 8E D8 A0 00 00-8A 1E 01 00 2A C3 A3 02 ............*... 0B97:0020 00 CC 86 72 FF 77 15 8A-86 70 FF 2A E4 50 B8 FD ...r.w...p.*.P.. 0B97:0030 05 50 FF 36 24 21 E8 77-63 83 C4 06 FF 36 24 21 .P.6$!.wc....6$! 0B97:0040 B8 0A 00 50 E8 47 5E 83-C4 04 5E 8B E5 5D C3 90 ...P.G^...^..].. 0B97:0050 55 8B EC 81 EC 84 00 C4-5E 04 26 80 7F 0A 00 74 U.......^.&....t 0B97:0060 3E 8B 46 08 8B 56 0A 89-46 FC 89 56 FE C4 5E FC >.F..V..F..V..^. 0B97:0070 26 8A 47 0C 2A E4 40 50-8B C3 05 0C 00 52 50 E8 &.G.*[email protected]. -q C:\TASM>