102 lines
2 KiB
ArmAsm
Executable file
102 lines
2 KiB
ArmAsm
Executable file
;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
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;; A file containing 16-bit macro arithmatic.
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;; You may add ,! ass a 5:th parameter to skipp flagg clearing.
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;; This will make it run faster but will have unintended behavior.
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;;Se below for some fast 16bit logic
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;;http://6502.org/tutorials/compare_beyond.html
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;; Addition uses the A register
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;; a = a + b
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.macro Add_16 a_low, a_hi, b_low, b_hi, fast_unsafe
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;; IF to run it fast
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.ifblank fast_unsafe
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CLC
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.endif
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LDA b_low
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ADC a_low
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STA a_low
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LDA b_hi
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ADC a_hi
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STA a_hi
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.endmacro
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;; Untested!
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;; Addition uses the A register
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;; a = a + b. b_low = A, b_hi = X
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.macro Add_16_AX low, hi, fast_unsafe
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;; IF to run it fast
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.ifblank fast_unsafe
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CLC
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.endif
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ADC low
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STA low
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TXA
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ADC hi
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STA hi
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.endmacro
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;; Subtraction uses the A register
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;; a = a - b
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.macro Sub_16 a_low, a_hi, b_low, b_hi, fast_unsafe
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;; IF to run it fast
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.ifblank fast_unsafe
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SEC
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.endif
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LDA a_low
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SBC b_low
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STA a_low
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LDA a_hi
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SBC b_hi
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STA a_hi
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.endmacro
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;; Untested
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;; Subtraction uses the A register
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;; a = a - b. b_low = A, b_hi = X
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.macro Sub_16_AX low, hi, fast_unsafe
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;; IF to run it fast
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.ifblank fast_unsafe
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SEC
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.endif
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SBC low
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STA low
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TXA
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SBC hi
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STA hi
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.endmacro
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;; Multiplication of 2
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;; a = a*2
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.macro mult_16 low_, hi_, NOT_ROL
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;; IF NOT_ROL
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.ifblank fast_unsafe
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ASL low_
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ROL hi_
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.else
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ROL low_
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ROL hi_
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.endif
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.endmacro
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.macro Mov_16 a_low, a_hi, b_low, b_hi
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LDA b_low
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STA a_low
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LDA b_hi
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STA a_hi
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.endmacro
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;;Larger then operation, uses the A register
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;;IF a < b then: jump to label
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; C =0 if jump to LABEL
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.macro Lag_16 a_low, a_hi, b_low, b_hi, label ; [low, hi] = [low, hi]*2
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LDA a_hi
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CMP b_hi
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BCC label
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BNE LABEL
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LDA a_low
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CMP b_low
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BCC label
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LABEL:
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.endmacro
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