!DISP_REG = $2100 ; Screen Display Register !VMAIN_REG = $2115 ; Video Port Control Register !VRAM_LOW_REG = $2116 ; VRAM Address Registers (Low) !VRAM_HIGH_REG = $2117 ; VRAM Address Registers (High) !VRAM_WRITE_REG = #$18 ; VRAM Data Write Registers (Low) (you always store it to the dest register so no need for the actual address) !DMA0_REG = $4300 ; DMA Control Register - channel 0 !DMA0_DEST_REG = $4301 ; DMA Destination Register !DMA0_SRC_LOW_REG = $4302 ; DMA Source Address Register (Low) !DMA0_SRC_HIGH_REG = $4303 ; DMA Source Address Register (High) !DMA0_SRC_BANK_REG = $4304 ; DMA Source Address Register (Bank) !DMA0_SIZE_LOW_REG = $4305 ; DMA Size Registers (Low) !DMA0_SIZE_HIGH_REG = $4306 ; DMA Size Registers (Low) !DMA_ENABLE_REG = $420B ; DMA Enable Register macro DMA_VRAM(VRAM_HIGH,VRAM_LOW,SRC_BANK,SRC_HIGH,SRC_LOW,LENGTH_HIGH,LENGTH_LOW) PHA ; --- preserve DMA registers ---------------------------------------------------- LDA !DMA0_REG : PHA LDA !DMA0_DEST_REG : PHA LDA !DMA0_SRC_LOW_REG : PHA LDA !DMA0_SRC_HIGH_REG : PHA LDA !DMA0_SRC_BANK_REG : PHA LDA !DMA0_SIZE_LOW_REG : PHA LDA !DMA0_SIZE_HIGH_REG : PHA ; ------------------------------------------------------------------------------- ;LDA.b #$80 : STA !DISP_REG ; force vblank LDA #$80 : STA !VMAIN_REG ; write to vram at $<VRAM_HIGH><VRAM_LOW> LDA <VRAM_LOW> : STA !VRAM_LOW_REG ; Set VRAM destination address low byte LDA <VRAM_HIGH> : STA !VRAM_HIGH_REG ; Set VRAM destination address high byte ; Set DMA0 to write a word at a time. LDA #$01 STA !DMA0_REG ; Write to $2118 & $2119 - VRAM Data Write Registers (Low) & VRAM Data Write Registers (High) ; setting word write mode on DMA0_REG causes a write to $2118 and then $2119 ; $21xx is assumed LDA #$18 STA !DMA0_DEST_REG ; Read from $<SRC_BANK>:<SRC_HIGH><SRC_LOW>. LDA.b <SRC_LOW> STA !DMA0_SRC_LOW_REG ; set src address low byte LDA.b <SRC_HIGH> STA !DMA0_SRC_HIGH_REG ; set src address high byte LDA.b <SRC_BANK> STA !DMA0_SRC_BANK_REG ; set src address bank byte ; total bytes to copy: #$1000 bytes. LDA <LENGTH_LOW> : STA $4305 ; length low byte LDA <LENGTH_HIGH> : STA $4306 ; length high byte ; start DMA on channel 0 LDA #$01 ; channel select bitmask STA !DMA_ENABLE_REG ; --- restore DMA registers ----------------------------------------------------- PLA : STA !DMA0_SIZE_HIGH_REG PLA : STA !DMA0_SIZE_LOW_REG PLA : STA !DMA0_SRC_BANK_REG PLA : STA !DMA0_SRC_HIGH_REG PLA : STA !DMA0_SRC_LOW_REG PLA : STA !DMA0_DEST_REG PLA : STA !DMA0_REG ; ------------------------------------------------------------------------------- PLA endmacro