34 lines
418 B
ArmAsm
34 lines
418 B
ArmAsm
.define Rol4
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! This subroutine rotates left a fourbyte integer n times.
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! N is in register X.
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Rol4:
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txa
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bne 1f ! a zero rotate skip
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rts
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1: tay
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jsr Pop
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stx ARTH
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sta ARTH+1
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jsr Pop
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stx ARTH+2
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sta ARTH+3
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2: asl ARTH
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rol ARTH+1
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rol ARTH+2
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rol ARTH+3 ! rotate left
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bcc 1f
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inc ARTH ! put carry in rightmost bit
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1: dey
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bne 2b
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ldx ARTH+2
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lda ARTH+3
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jsr Push
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ldx ARTH
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lda ARTH+1
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jmp Push
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