aboutsummaryrefslogtreecommitdiffstats
path: root/engine/gfx/oam_dma.asm
diff options
context:
space:
mode:
Diffstat (limited to 'engine/gfx/oam_dma.asm')
-rw-r--r--engine/gfx/oam_dma.asm26
1 files changed, 26 insertions, 0 deletions
diff --git a/engine/gfx/oam_dma.asm b/engine/gfx/oam_dma.asm
new file mode 100644
index 00000000..b0d64675
--- /dev/null
+++ b/engine/gfx/oam_dma.asm
@@ -0,0 +1,26 @@
+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: