27 lines
681 B
ArmAsm
27 lines
681 B
ArmAsm
;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
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;;I thoughtout russan thing
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;;X * %1111001
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;;= X + X*%1111000
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;;= X + X*%1000 *%11111
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;; to remember this for later, for duuqnds papper
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.proc mult; user-procedure :clobbers A :clobbers-arguments 2
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;; https://en.wikipedia.org/wiki/Ancient_Egyptian_multiplication#Russian_peasant_multiplication
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.include "arithmatic.inc"
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LDA #$00
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loop:
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ASL VAL_B
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ROR VAL_A; add to awnser if VAL_A is odd
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BCC loop
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LSR VAL_B
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ADC VAL_B; add val_b because val_a was odd.
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ASL VAL_B
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BNE loop
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endloop:
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RTS
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.endproc
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