want to trace point betwen two memory address, write operation
DOS 6.22 ml 6.11
_DR7 proc
mov eax,cr4 ; ask debug facilities in CR4
add eax,18h
mov cr4,eax
mov eax,ebx; start address
mov dr0, eax
add ebx,50000
mov eax,ebx; ; end address
mov dr1, eax
; enable DR0 and DR1 for memory access
mov eax,00000000000100010000001000001010b
mov dr7,eax
push ds
push cs
pop ds
mov ax,02501h ; Set new Int_1
mov dx,offset NewInt1
int 021h
pop ds
ret
_DR7 endp
work but only start address. Not full area betwen start address and end address.
Possible?
Please help?
I want to check 50000 byte in code segment.
then drx is not the way to go.. if you want to monitor a memory / code / whatever area, virtualprotect (PAGE_GUARD) + seh are most likely your best bet....
ok.
detecting my problem.
My program not bad.
Error in dos loader.
program code segment size 40K, data segment size 40K
datasegment loading after code segment.
Dos loader writing some byte cs:fff0.
this address in my data area, my program crashed.
work around:
data segment inserting 20k 0
but uggly and ....
dos loader writing 4 byte cs:0fffch.
writing my program entry point address (offset and segment)
But this area my program data area.
???????
For a COM file, after the loader has created a stack, it pushes a zero word onto the stack for compatibility with programs designed for early versions of MS-DOS (where a COM program could terminate itself by executing a near return with the stack in its initial state). Assuming the loader was able to allocate at least 64KB, SP would have been initialized to zero, and the pushed zero would end up at offset address FFFCh.
didnt realise post was for 16 bit... eew...
:dazzled:
what is it you're trying to do exactly?