Difference between revisions of "84PCE:Syscalls:021D80"
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ld (0D02AD7h), hl | ld (0D02AD7h), hl | ||
bit 7, b ; This should be h, not b | bit 7, b ; This should be h, not b | ||
| − | jr z, | + | jr z, +_ |
dec a | dec a | ||
| − | _ | + | _: |
ld (0D02AD9h), a | ld (0D02AD9h), a | ||
ld de, (0D02AD7h) | ld de, (0D02AD7h) | ||
pop af | pop af | ||
ret </nowiki> | ret </nowiki> | ||
Revision as of 14:01, 1 September 2015
Synopsis
Hypothesized Official Name: SignExtendHL_broken
Syscall Address: 021D80h
This is supposed to extend the signed 16-bit HL value to be 24-bit signed.
However, due to what looks like a copy-paste error by TI, this routine is pretty much useless.
It looks like they tried to use code from SignExtendBC, and forgot to change a byte.
Here is what this routine calls, if you can find a particular use for it, go for it.
SignExtendHL_broken: push af xor a ld (0D02AD7h), hl bit 7, b ; This should be h, not b jr z, +_ dec a _: ld (0D02AD9h), a ld de, (0D02AD7h) pop af ret
