kep-hack/engine/gfx/oam_dma.asm
2020-07-07 11:10:29 -04:00

27 lines
419 B
NASM

WriteDMACodeToHRAM::
; Since no other memory is available during OAM DMA,
; DMARoutine is copied to HRAM and executed there.
ld c, LOW(hDMARoutine)
ld b, DMARoutineEnd - DMARoutine
ld hl, DMARoutine
.copy
ld a, [hli]
ldh [c], a
inc c
dec b
jr nz, .copy
ret
DMARoutine:
; initiate DMA
ld a, HIGH(wOAMBuffer)
ldh [rDMA], a
; wait for DMA to finish
ld a, $28
.wait
dec a
jr nz, .wait
ret
DMARoutineEnd: