Re: A86: arg... sqrtKEY again...
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Re: A86: arg... sqrtKEY again...
Could it possibly that you make the jump 4 times? One of them most likely
ends up there, even without the three bytes to test with...
Glen
tutorial1.cjb.net
In a message dated 11/12/99 8:15:58 PM Eastern Standard Time,
croop@oregontrail.net writes:
>
> The following code should copy three bytes from the sixth byte of the
> sqrtKEY program variable to a location called id_tag_copy. Once there,
> the three bytes are tested to see if they are appropriate values. My
> problem is that the bytes never get copied; after the 'rst 20h', I check
> to see if the var even exists; if it doesn't, it jumps to a routine
> called memlock_compromised. THIS ALWAYS HAPPENS. The emulator tells me
> there is a var called (sqrt)KEY, but _findsym apparently returns saying
> it doesn't exist. Now, what's REALLY spooky, is that I changed the 'jr
> c,...' to 'jr nc,...' in case I had the _findsym output backwards in my
> head. IT STILL MADE THE JUMP. HOW? WHY? No matter what I do, it
> alwasy makes that jump, according to the emulator. The bytes never get
> copied. Can someone point out the probably obvious error I have made?
>
> Cassady Roop
>
>
> ld hl, $5A92 ;name of sqrtkey program
> rst 10h ;move to OP1
> rst 20h ;_findsym
> jr c, memlock_compromised ;if carry, then sqrtKEY doesn't exist.
> ld hl, $0006 ;adjust for the asm marker & size word, and jr
> instruction
> xor a ;adding two 24-bit values
> add hl,de ;add offset
> adc a,b ;incase it went off a RAM page
> call _SET_ABS_SRC_ADDR
> xor a
> ld hl, id_tag_copy ;copy to a temp location
> call _SET_ABS_DEST_ADDR
> ld bc, $0003
> call _SET_MM_NUM_BYTES
> call _mm_ldir
> ld hl, id_tag_copy
> ld a, (hl) ;take a look at the id tag we ripped off the sqrtKEY
> program
> cp 'L' ;id tag of 'LDN' identifies it as lockdown's memlock
module
> jr nz, memlock_compromised ;if not L, then it was deleted by another
> prog
> inc hl
> ld a, (hl)
> cp 'D'
> jr nz, memlock_compromised
> inc hl
> ld a, (hl)
> cp 'N'
> jr nz, memlock_compromised
>
Glen
tutorial1.cjb.net
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