diff options
Diffstat (limited to 'test.s')
| -rw-r--r-- | test.s | 67 |
1 files changed, 67 insertions, 0 deletions
@@ -0,0 +1,67 @@ +.MEMORYMAP
+SLOTSIZE $2000
+DEFAULTSLOT 0
+SLOT 0 $C000
+SLOT 1 $E000
+.ENDME
+
+.ROMBANKMAP
+BANKSTOTAL 2
+BANKSIZE $2000
+BANKS 2
+.ENDRO
+
+
+ .bank 0
+ .org $0000
+RESET:
+ SEI ; disable IRQs
+ CLD ; disable decimal mode
+ LDX #$40
+ STX $4017.W ; disable APU frame IRQ
+ LDX #$FF
+ TXS ; Set up stack
+ INX ; now X = 0
+ STX $2000.W ; disable NMI
+ STX $2001.W ; disable rendering
+ STX $4010.W ; disable DMC IRQs
+
+vblankwait1: ; First wait for vblank to make sure PPU is ready
+ BIT $2002
+ BPL vblankwait1
+
+clrmem:
+ LDA #$00
+ STA $0000, x
+ STA $0100, x
+ STA $0200, x
+ STA $0400, x
+ STA $0500, x
+ STA $0600, x
+ STA $0700, x
+ LDA #$FE
+ STA $0300, x
+ INX
+ BNE clrmem
+
+vblankwait2: ; Second wait for vblank, PPU is ready after this
+ BIT $2002
+ BPL vblankwait2
+
+ LDA #%10000000 ;intensify blues
+ STA $2001
+
+Forever:
+ JMP Forever ;jump back to Forever, infinite loop
+
+NMI:
+ RTI
+
+
+ .bank 1 slot 1
+ .orga $FFFA ;first of the three vectors starts here
+ .dw NMI ;when an NMI happens (once per frame if enabled) the
+ ;processor will jump to the label NMI:
+ .dw RESET ;when the processor first turns on or is reset, it will jump
+ ;to the label RESET:
+ .dw 0 ;external interrupt IRQ is not used in this tutorial
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