kep-hack/engine/oam_dma.asm
Rangi 4b853ad676
Separate maps.asm, pics.asm, sprites.asm, and tilesets.asm from main.asm (#251)
Each new file builds its own .o, along with separate main.o and home.o, which necessitates many more "exported::" labels.
2020-06-27 15:32:24 -04:00

27 lines
420 B
NASM

WriteDMACodeToHRAM::
; Since no other memory is available during OAM DMA,
; DMARoutine is copied to HRAM and executed there.
ld c, $ff80 % $100
ld b, DMARoutineEnd - DMARoutine
ld hl, DMARoutine
.copy
ld a, [hli]
ld [$ff00+c], a
inc c
dec b
jr nz, .copy
ret
DMARoutine:
; initiate DMA
ld a, wOAMBuffer / $100
ld [rDMA], a
; wait for DMA to finish
ld a, $28
.wait
dec a
jr nz, .wait
ret
DMARoutineEnd: