itty-bitty-vtty/vt100.tabs.S
2021-09-21 23:40:22 -04:00

78 lines
634 B
ArmAsm

lst off
rel
xc
xc
use vt.equ
mx %11
init_tabs ent
ldx #80-1
:zloop stz tabs,x
dex
bpl :zloop
lda #$80
ldy #8
:loop ldx :table,y
sta tabs,x
dey
bpl :loop
rts
:table db 8*1,8*2,8*3,8*4,8*5,8*6,8*7,8*8,8*9
set_tab ent
* input x = x
* ldx x
cpx #80
bge :rts
lda #$80
sta tabs,x
:rts rts
reset_tab ent
* input x = x
* ldx x
cpx #80
bge :rts
stz tabs,x
:rts rts
reset_all_tabs ent
ldx #80-1
:loop stz tabs,x
dex
bpl :loop
rts
next_tab_stop ent
* input x = x
* ldx x
inx
cpx #79
bge :79
:loop bit tabs,x
bmi :rts
inx
cpx #80
bcc :loop
:79 ldx #79
:rts rts
tabs ds 80
sav vt100.tabs.L