Hi,
I am fairly new to NES development and i am having some troubles when it comes to the NMI thread.
My code is based on the cc65 examples by Shiru:
it looks to me like the VRAM_UPDATE bytes never change. Am i missing something in my understanding of how this works?
I am fairly new to NES development and i am having some troubles when it comes to the NMI thread.
My code is based on the cc65 examples by Shiru:
Code:
nmi:
pha
txa
pha
tya
pha
lda <VRAM_UPDATE
bne @update
jmp @skipUpd
@update:
;never gets here
@skipUpd:
;always gets here
pha
txa
pha
tya
pha
lda <VRAM_UPDATE
bne @update
jmp @skipUpd
@update:
;never gets here
@skipUpd:
;always gets here
it looks to me like the VRAM_UPDATE bytes never change. Am i missing something in my understanding of how this works?