mirror of
https://github.com/ksherlock/itty-bitty-vtty.git
synced 2024-05-29 09:41:33 +00:00
6e0de284e0
to handle DECAWM mode, bit 7 of x ($80 + 79) indicates a wrap is imminent, as opposed to just being in column 79. backspace, etc will drop back to column 78 (based on testing).
78 lines
635 B
ArmAsm
78 lines
635 B
ArmAsm
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lst off
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rel
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xc
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xc
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use vt.equ
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mx %11
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init_tabs ent
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ldx #80-1
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:zloop stz tabs,x
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dex
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bpl :zloop
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lda #$80
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ldy #8
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:loop ldx :table,y
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sta tabs,x
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dey
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bpl :loop
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rts
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:table db 8*1,8*2,8*3,8*4,8*5,8*6,8*7,8*8*,8*9
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set_tab ent
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* input x = x
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* ldx x
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cpx #80
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bge :rts
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lda #$80
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sta tabs,x
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:rts rts
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reset_tab ent
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* input x = x
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* ldx x
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cpx #80
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bge :rts
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stz tabs,x
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:rts rts
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reset_all_tabs ent
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ldx #80-1
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:loop stz tabs,x
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dex
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bpl :loop
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rts
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next_tab_stop ent
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* input x = x
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* ldx x
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inx
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cpx #79
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bge :79
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:loop bit tabs,x
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bmi :rts
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inx
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cpx #80
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bcc :loop
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:79 ldx #79
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:rts rts
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tabs ds 80
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sav vt100.tabs.L
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