Re: A86:OnTemp.asm
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Re: A86:OnTemp.asm
One byte smaller :-)
ld hl,_alt_on_exec
ld a,(hl)
dec hl
push hl
ld de,40
ld b,5
getchecksum:
add hl,de
add a,(hl)
djnz getchecksum
pop hl
ld (hl),a
In a message dated Thu, 13 Jan 2000 1:13:24 AM Eastern Standard Time, "David Phillips" <david@acz.org> writes:
>
> > Of course, there are much more efficient ways of getting checksums, but...
>
> I might have screwed this up a bit, it's been a while and I did this from
> memory. This should be the most efficient way to calculate checksums. Note
> that the ROM uses the method you posted: loading constant values into HL (of
> course it does it backwards).
>
> CalcChecksum:
> ld hl,alt_on_exec
> ld a,(hl)
> dec hl
> ld b,5
> ld de,$28
> @loop:
> add hl,de
> add a,(hl)
> djnz @loop
> ld (alt_on_chksum),a
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