84PCE:Syscalls:021D7C
From WikiTI
Revision as of 18:39, 4 May 2015 by MateoConLechuga (Talk | contribs)
Synopsis
Hypothesized Official Name: SignExtendDE_broken
Syscall Address: 021D7Ch
This is supposed to extend the signed 16-bit DE 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.
push af xor a ld (0D02AD7h), de bit 7, b ; This should be d, not b jr z, _+ dec a _+: ld (0D02AD9h), a ld de, (0D02AD7h) pop af ret
