diff options
Diffstat (limited to 'hacks/images/m6502/keftal.asm')
| -rw-r--r-- | hacks/images/m6502/keftal.asm | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/hacks/images/m6502/keftal.asm b/hacks/images/m6502/keftal.asm new file mode 100644 index 0000000..efb2982 --- /dev/null +++ b/hacks/images/m6502/keftal.asm @@ -0,0 +1,82 @@ +; awfully slow.. be patient + +init: + ldx #0 + stx $0 + inx + stx $2 + stx $3 + inx + stx $1 + +loop: + lda $2 + cmp #$20 + bne notIncF2 + inc $3 + lda #0 + sta $2 +notIncF2: + inc $2 + +; CALCULATE START + + lda $2 + sta $f1 + lda $2 + sta $f2 + jsr multiply + + lda $f4 + sta $f8 + + lda $3 + sta $f1 + lda $3 + sta $f2 + jsr multiply + +; CALCULATE STOP + + lda $f4 + clc + adc $f8 + + lsr + lsr + lsr + lsr + lsr + ldx #0 + sta ($0,x) + inc $0 + lda $0 + cmp #$00 + bne notNextY + inc $1 + lda $1 + cmp #6 + beq exit +notNextY: + jmp loop +exit: + rts + +multiply: + lda #0 + sta $f4 + sta $f5 + ldx #8 +a:asl $f4 + rol $f5 + asl $f2 + bcc b + clc + lda $f4 + adc $f1 + sta $f4 + bcc b + inc $f5 +b:dex + bne a + rts
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