mirror of
https://github.com/mach-kernel/mrbuffer.git
synced 2024-06-01 12:41:36 +00:00
268 lines
2.6 KiB
ArmAsm
268 lines
2.6 KiB
ArmAsm
rel
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typ $B3
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dsk main.l
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; this doesn't actually modeset the cpu
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mx %00
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phk
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plb
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; we're going to enter into emulation mode, so we can toggle softswitches
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; doing so clobbers our stack pointer and supposedly other things so let's
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; save the state of as many things as we can.
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ncpui da
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nstack da
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; cpu status register first
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php
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pla
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sta ncpui
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; the stack pointer too
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tsc
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sta nstack
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; enable emulation mode, tell merlin we did so
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sec
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xce
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sep #$30
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mx %11
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; the manuals all seem to use zero page addresses, so we'll oblige and slide
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; the DP offset all the way up and go to bank 00
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lda $0000
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pha
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pld
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lda $00
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pha
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plb
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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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sta $C000 ; disable 80 column store?
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sta $C00C ; disable 80 column hardware?!
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* sta $C050 ; set standard apple ii gfx mode
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sta $C051 ; select text mode only. "only"?
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lda $C054 ; select text page 1 (there are 2)
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* lda $C056 ; select "low res" graphics
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lda $CF
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sta $0400
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sta $0480
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*; let's write more interesting (broken)
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*mood asc "this is excruciating"
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*nult db
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* lda $00
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* sta nult ; i.e null terminator
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*loop clc
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* ldx #0
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* lda mood,x
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* cmp $00
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* sta $040,x
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* inx
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* bcc loop
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* brk
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*EPOC2
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* clc
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* xce
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* rep #$30
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*; disable emulation mode
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* mx %00
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* brk
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*; load a char and write it to the 40 char text buffer
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*bois lda "B"
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* sta $E00400
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* sta $E00401
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* sta $E00402
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* jmp bois
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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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