diff options
Diffstat (limited to 'init.gbasm')
| -rw-r--r-- | init.gbasm | 30 |
1 files changed, 22 insertions, 8 deletions
@@ -5,7 +5,7 @@ VBlank: .PADTO 0x0100 Start: - JP =Empty_VRAM + JP =Initialize_RAM .PADTO 0x0104 Nintendo_Logo: ; The Nintendo logo must be stored in bytes 0x104-133 @@ -18,10 +18,29 @@ Checksum: ; The bytes 0x134-0x14d need to add up to 0xe7 (= 0xff - 0x19) .DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00 .DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$e7 +Initialize_RAM: +Empty_WRAM: + LD HL, $C000 + Empty_WRAM.loop: + XOR A + LD (HL+), a + LD a, $D0 + CP h + JR NZ, =Empty_WRAM.loop + +Wait_VBlank: + LD A, $reg_lcd_status + AND $03 + CP $01 + JR NZ, =Wait_VBlank + + ; LCDC + XOR A + LD $reg_lcd_controller, A + Empty_VRAM: ; (Clear screen) LD hl, $VRAM_start ; We set the HL register to the start of VRAM - -Empty_VRAM.loop: + Empty_VRAM.loop: XOR A LD (HL+), a ; We set the memory pointed to by HL to 0 and increase HL LD a, $a0 @@ -36,11 +55,6 @@ Empty_VRAM.loop: LD A, $e4 LD $reg_obj0_palette, A - ; LCDC - LD A, $reg_lcd_controller - OR $06 - LD $reg_lcd_controller, A - ; Interrupts LD A, $01 LD $reg_interrupt_enable, A |