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Digital-Research-Source-Code/CONTRIBUTIONS/z80em86/support/video.mac
Sepp J Morris 31738079c4 Upload
Digital Research
2020-11-06 18:50:37 +01:00

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;**************************************************************************
;* *
;* VIDEO v1.00 turns video ON or OFF S.J.Kay 22/04/95 *
;* *
;* Support utility for CP/M 3 *
;* *
;**************************************************************************
maclib TPORTS.LIB
;
.z80
aseg
;
org 0100h
.phase 0100h
;
ld b,0 ;video on value
ld hl,0080h ;parameter address
ld c,(hl)
inc hl
chkchr: ld a,c ;characters to check
or a
jp z,video1
ld a,(hl) ;get a character
dec c
inc hl
cp ' ' ;ignore any leading spaces
jp z,chkchr
cp 'O' ;1st character must be 'O'
jp nz,video1
ld a,(hl) ;2nd character
cp 'F' ;video off if 2nd char is 'F'
jp nz,video1
dec b ;video off value
video1: ld a,b
out (vidset),a ;turn video on/off
ret
;
.dephase
end