Category : System Diagnostics for your computer
Archive   : 386POPAD.ZIP
Filename : 386BUGS.ASM

.386
;
; BUGTST.ASM - By: John Lauro
; Based on bug found by Jeff Prothero
;
DATA SEGMENT USE16 PUBLIC
MOK DB 'POPAD ok',13,10,'$'
MNOTOK DB '*** POPAD fails test ***',13,10,'$'
DATA ENDS
;
;
STKSEG SEGMENT USE16 STACK
DW 100 DUP(?)
STKSEG ENDS
;
;
CODE SEGMENT USE16 PUBLIC
ASSUME CS:CODE,SS:STKSEG,DS:DATA
CODES PROC FAR
START: MOV AX,DATA
MOV DS,AX

mov eax,12345678
mov edx, 0
mov edi, 0
pushad
popad

; The instruction immediately following popad is the critical
; instruction. Simple fix, insert a NOP after popad.

mov ecx, [edx+edi]

cmp eax, 12345678
je ok
mov dx, offset mnotok
outmsg: mov ah, 09h ; ConStringOutput
int 21h

mov ah, 4ch ; Exit
mov al, 0
int 21h

ok: mov dx, offset mok
jmp outmsg

CODES ENDP
CODE ENDS
END START