40 lines
999 B
ArmAsm
Executable file
40 lines
999 B
ArmAsm
Executable file
;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
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;; Sets memory in 'A'-registry to all addresses from 'A_start' until 'A_start' + 'length'
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;; Modifies A, X and A_start
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.proc memset
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.include "mem.inc"
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;; big_set sets the memory in $ff chunks.
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;; skipp if length >= $ff
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LDX length +1
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BNE big_set
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JMP small_set
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big_set: ;sets $ff of memory
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;; Y value do not matter, will go through all anyway!
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.repeat $ff
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STA (A_start), Y
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DEY
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.endrepeat
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STA (A_start), Y ; dont forget Y =0
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big_set_end:
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;;set all hole $ff memory chunks!
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INC A_start + 1
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DEX ;; length +1 --
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BEQ small_set
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JMP big_set
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;;sets the rest of the memory
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;; note that this can use code above (smc) or the same method. may implement later.
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small_set:
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LDY length
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small_set_loop:
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STA (A_start), Y
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DEY
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BNE small_set_loop
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STA (A_start), Y
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RTS
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.endproc
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