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https://github.com/mach-kernel/mrbuffer.git
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65 lines
1.6 KiB
ArmAsm
65 lines
1.6 KiB
ArmAsm
rel
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typ $B3
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dsk main.l
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; ensure 16-bit mode (unnecessary?)
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clc
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xce
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rep #$20
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phk
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plb
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; half bank for accumulator, you don't want to toggle them on then back off, right?
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sep #$30
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; toggle the softswitches; they don't take any values. some are only triggered
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; by writes, $C054 can be triggered by a read
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stal $00C000 ; disable 80 column store?
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stal $00C00C ; disable 80 column hardware?!
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stal $00C050 ; set standard apple ii gfx mode
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stal $00C051 ; select text mode only. "only"?
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ldal $00C054 ; select text page 1 (there are 2)
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ldal $00C056 ; select "low res" graphics
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rep #$30 ; go back to 16-bit mode
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; show the current char on screen
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; first check and discard to clear strobe, then enter loop
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ldal $00C010
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:eloop ldal $00C010
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stal $000400
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jmp :eloop
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; working text blit
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* ldx #hithere+2 ; strl, first two bytes are strlen, # denotes immediate addr val
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* ldy #$0400 ; start of text buffer on 00
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* ldal hithere
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* dec
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* mvn $02, $00
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* brk
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; Important locations
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SPEAKER equ $E0C030
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PRODOS16 equ $E100A8
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jsl PRODOS16
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; This exit code is "device busy", why is it the only one
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; that works?!
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da $29
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adrl QP
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bcs ERROR
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ERROR brk
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QP adrl $0000
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da $00
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hithere strl "this was excruciating"
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