mirror of
https://github.com/ksherlock/itty-bitty-vtty.git
synced 2024-09-27 07:54:29 +00:00
629 lines
6.6 KiB
ArmAsm
629 lines
6.6 KiB
ArmAsm
lst off
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exp off
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xc
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xc
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rel
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* vt52 emulator.
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* not supported - graphics, screen hold.
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*
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*
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*
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*
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SET80VID equ $c00d
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SETALTCHAR equ $c00f
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TXTSET equ $c051
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ent init,main,vt52
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dum 0
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text00 adrl 0
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text01 adrl 0
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state dw 0
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mode dw 0
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x dw 0
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y dw 0
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* cursor
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cursor_ptr adrl 0
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cursor_saved_char dw 0
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cursor_state dw 0
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dend
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mx %11
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main
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clc
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xce
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cli
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jsr init
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mx %00
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loop
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sep #$30
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lda $c000
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bmi :key
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bra loop
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:key
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lda $c010
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ldx $c025 ; keymod
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and #$7f
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jsr vt52
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bra loop
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:loop wai
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bra :loop
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init
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sep #$30
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sta TXTSET
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sta SET80VID
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sta SETALTCHAR
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rep #$30
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stz x
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stz y
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stz mode
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stz state
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lda #$0400
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sta text00
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stz text00+2
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sta text01
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lda #$0001
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sta text01+2
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jmp clear_all
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cc mac
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ldx #38
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]loop sta ]1,x
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stal $010000+]1,x
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dex
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dex
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bpl ]loop
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<<<
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cp mac
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ldx #38
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]loop lda ]1,x
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sta ]2,x
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ldal $010000+]1,x
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stal $010000+]2,x
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dex
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dex
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bpl ]loop
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<<<
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clear_eol
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sep #$20
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lda x
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lsr
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tay
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lda #" "
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bcc :even
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sta (text00),y
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iny
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:even
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cpy #80/2
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bcs :rts
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sta [text01],y
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sta (text00),y
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iny
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cpy #40
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bra :even
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:rts rep #$20
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rts
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clear_eos
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lda x
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ora y
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beq clear_all
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lda x
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beq :x0
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jsr clear_eol
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lda y
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inc
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bra :x1
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:x0
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lda y
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:x1 cmp #23
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bcs :rts
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asl
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tax
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lda #" "
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jmp (clear_table,x)
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:rts rts
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clear_all
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lda #" " ; high bit
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c00 cc $0400
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c01 cc $0480
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c02 cc $0500
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c03 cc $0580
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c04 cc $0600
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c05 cc $0680
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c06 cc $0700
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c07 cc $0780
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c08 cc $0428
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c09 cc $04a8
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c10 cc $0528
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c11 cc $05a8
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c12 cc $0628
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c13 cc $06a8
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c14 cc $0728
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c15 cc $07a8
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c16 cc $0450
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c17 cc $04d0
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c18 cc $0550
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c19 cc $05d0
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c20 cc $0650
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c21 cc $06d0
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c22 cc $0750
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c23 cc $07d0
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rts
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clear_table
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dw c00,c01,c02,c03,c04,c05,c06,c07,c08,c09
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dw c10,c11,c12,c13,c14,c15,c16,c17,c18,c19
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dw c20,c21,c22,c23
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scroll_down
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cp $0480;$0400
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cp $0500;$0480
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cp $0580;$0500
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cp $0600;$0580
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cp $0680;$0600
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cp $0700;$0680
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cp $0780;$0700
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cp $0428;$0780
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cp $04a8;$0428
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cp $0528;$04a8
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cp $05a8;$0528
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cp $0628;$05a8
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cp $06a8;$0628
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cp $0728;$06a8
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cp $07a8;$0728
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cp $0450;$07a8
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cp $04d0;$0450
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cp $0550;$04d0
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cp $05d0;$0550
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cp $0650;$05d0
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cp $06d0;$0650
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cp $0750;$06d0
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cp $07d0;$0750
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lda #" "
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cc $07d0
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rts
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scroll_up
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cp $0750;$07d0
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cp $06d0;$0750
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cp $0650;$06d0
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cp $05d0;$0650
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cp $0550;$05d0
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cp $04d0;$0550
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cp $0450;$04d0
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cp $07a8;$0450
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cp $0728;$07a8
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cp $06a8;$0728
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cp $0628;$06a8
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cp $05a8;$0628
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cp $0528;$05a8
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cp $04a8;$0528
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cp $0428;$04a8
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cp $0780;$0428
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cp $0700;$0780
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cp $0680;$0700
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cp $0600;$0680
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cp $0580;$0600
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cp $0500;$0580
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cp $0480;$0500
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cp $0400;$0480
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lda #" "
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cc $0400
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rts
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draw_char
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; a = char to draw
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ora #$80
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tax
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lda x
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lsr
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tay
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txa
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bcs :odd
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sep #$20
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sta [text01],y
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rep #$20
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inc x
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jmp update_cursor
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:odd
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sep #$20
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sta (text00),y
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rep #$20
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lda x
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cmp #79
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bcs :rts
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inc x
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:rts jmp update_cursor
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text
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dw $0400
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dw $0480
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dw $0500
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dw $0580
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dw $0600
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dw $0680
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dw $0700
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dw $0780
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dw $0428
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dw $04a8
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dw $0528
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dw $05a8
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dw $0628
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dw $06a8
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dw $0728
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dw $07a8
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dw $0450
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dw $04d0
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dw $0550
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dw $05d0
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dw $0650
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dw $06d0
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dw $0750
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dw $07d0
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* based on testing, control handling happens first. ESC within an ESC Y sequence resets to ESC state.
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vt52
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mx %11
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and #$7f
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cmp #' '
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bcs :normal
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asl
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tax
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rep #$30
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jmp (ctrl_table,x)
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:normal
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ldx state
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rep #$30
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jmp (st_table,x)
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st_table
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dw state_0,state_1,state_2,state_3
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state_0
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and #$7f
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cmp #$7f
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beq :rts
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jsr draw_char
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:rts
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rts
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state_1 ; ESC encountered
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:MIN equ '<'
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:MAX equ '\'
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stz state
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and #$7f
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cmp #:MIN
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bcc :rts
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cmp #:MAX+1
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bcs :rts
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sec
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sbc #:MIN
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asl
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tax
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jmp (:table,x)
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:rts
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rts
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:table
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dw esc_lt ; <
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dw esc_eq ; =
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dw esc_gt ; >
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dw :rts ; ?
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dw :rts ; @
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dw esc_A ; A
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dw esc_B ; B
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dw esc_C ; C
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dw esc_D ; D
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dw :rts ; E
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dw esc_F ; F
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dw esc_G ; G
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dw esc_H ; H
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dw esc_I ; I
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dw esc_J ; J
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dw esc_K ; K
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dw :rts ; L
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dw :rts ; M
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dw :rts ; N
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dw :rts ; O
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dw :rts ; P
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dw :rts ; Q
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dw :rts ; R
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dw :rts ; S
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dw :rts ; T
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dw :rts ; U
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dw :rts ; V
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dw :rts ; W
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dw :rts ; X
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dw esc_Y ; Y
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dw esc_Z ; Z
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dw esc_[ ; [
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dw esc_\ ; \
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state_2 ; ESC Y encountered, part 1
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* out of bounds line is ignored.
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inc state
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inc state
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and #$7f
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sec
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sbc #' '
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cmp #24
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bcs :rts
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sta y
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jmp update_cursor
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:rts rts
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state_3 ; ESC Y encountered, part 2
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* out of bounds column is ignored.
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* vt52 doc claims it moves to the rightmost column but this
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* doesn't reflect actual behavior.
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stz state
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and #$7f
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sec
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sbc #' '
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cmp #80
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bcs :rts
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sta x
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jmp update_cursor
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:rts rts
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ctrl_table
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dw ctrl_00,ctrl_01,ctrl_02,ctrl_03
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dw ctrl_04,ctrl_05,ctrl_06,ctrl_07
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dw ctrl_08,ctrl_09,ctrl_0a,ctrl_0b
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dw ctrl_0c,ctrl_0d,ctrl_0e,ctrl_0f
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dw ctrl_10,ctrl_11,ctrl_12,ctrl_13
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dw ctrl_14,ctrl_15,ctrl_16,ctrl_17
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dw ctrl_18,ctrl_19,ctrl_1a,ctrl_1b
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dw ctrl_1c,ctrl_1d,ctrl_1e,ctrl_1f
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ctrl_00
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ctrl_01
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ctrl_02
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ctrl_03
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ctrl_04
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ctrl_05
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ctrl_06
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ctrl_0b
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ctrl_0c
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ctrl_0e
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ctrl_0f
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ctrl_10
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ctrl_11
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ctrl_12
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ctrl_13
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ctrl_14
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ctrl_15
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ctrl_16
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ctrl_17
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ctrl_18
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ctrl_19
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ctrl_1a
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ctrl_1c
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ctrl_1d
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ctrl_1e
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ctrl_1f
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rts
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ctrl_07 ; ring the bell.
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rts
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ctrl_1b ; escape -
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lda #2
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sta state
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rts
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ctrl_09 ; tab
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lda x
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cmp #73
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bcs :one
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clc
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adc #8
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and #$07!$ff
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sta x
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bra :update
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:one
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cmp #79
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bcs :rts
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inc x
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:update
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jmp update_cursor
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:rts rts
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ctrl_0a ; line feed - cursor down w/ scroll
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lda y
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cmp #23
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blt :simple
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jmp scroll_down
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:simple
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inc y
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jmp update_cursor
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ctrl_0d ; carriage return - cursor to column 0.
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stz x
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jmp update_cursor
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esc_A ; cursor up w/o scroll
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lda y
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beq :rts
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dec y
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jmp update_cursor
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:rts rts
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esc_B ; cursor down w/o scroll
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lda y
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inc
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cmp #24
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bcs :rts
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inc y
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jmp update_cursor
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:rts rts
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esc_C ; cursor right w/o wrap
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lda x
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inc
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cmp #79
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bcs :rts
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inc x
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jmp update_cursor
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:rts rts
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esc_D ; cursor left w/o wrap
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ctrl_08 ; back space - cursor left w/o wrap
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lda x
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beq :rts
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dec x
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jmp update_cursor
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:rts rts
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esc_F ; enter graphics mode
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lda #%0010
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tsb mode
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rts
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esc_G ; exit graphics mode
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lda #%0010
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trb mode
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rts
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esc_H ; cursor home
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stz x
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stz y
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jmp update_cursor
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esc_I ; reverse line feed - cursor up w/ scroll
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lda y
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bne :simple
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jmp scroll_up
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:simple
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dec y
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jmp update_cursor
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esc_J ; erase to end of screen
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jmp clear_eos
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esc_K ; erase to end-of-line
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jmp clear_eol
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esc_Y ; direct cursor addressing
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lda #4
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sta state
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rts
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esc_Z ; identify terminal.
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; return ESC / K
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rts
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esc_[ ; enter hold screen mode
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lda #%0100
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tsb mode
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rts
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esc_\ ; exit hold screen mode
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lda #%0100
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trb mode
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rts
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esc_eq ; enter alternate keypad mode
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lda #%0001
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tsb mode
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rts
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esc_gt ; exit alternate keypad mode
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lda #%0001
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trb mode
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rts
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esc_lt ; vt100 - enter ANSI mode (exit vt52 mode).
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rts
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update_cursor
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* todo - cursor stuff.
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lda y
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asl
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tay
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lda text,y
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sta text00
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sta text01
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rts
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* lst on
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* sym on
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sav vt52.L
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