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|
;
; Christian Groessler, June 2004
;
; this file provides an equivalent to the BASIC GRAPHICS function
;
; int __fastcall__ _graphics(unsigned char mode);
;
;
.export __graphics
.import findfreeiocb
.import __oserror
.import fddecusage
.import clriocb
.import fdtoiocb
.import newfd
.import scrdev
.importzp tmp1,tmp2,tmp3
.include "atari.inc"
.include "errno.inc"
.code
; set new grapics mode
; gets new mode in A
; returns handle or -1 on error
; uses tmp1, tmp2, tmp3, tmp4 (in subroutines)
.proc __graphics
; tax
; and #15 ; get required graphics mode
; cmp #12
; bcs invmode ; invalid mode
; txa
; and #$c0 ; invalid bits set?
; bne invmode
; stx tmp1
sta tmp1 ; remember graphics mode
parmok: jsr findfreeiocb
beq iocbok ; we found one
lda #<EMFILE ; "too many open files"
seterr: jsr __mappederrno ; @@@ probably not correct to set errno here @@@
rts ; return -1
;invmode:ldx #>EINVAL
; lda #<EINVAL
; bne seterr
iocbok: txa
tay ; move iocb # into Y
lda #3
sta tmp3 ; name length + 1
lda #<scrdev
ldx #>scrdev
jsr newfd
tya
tax
bcs doopen ; C set: open needed
ldx #0
lda tmp2 ; get fd used
jsr fdtoiocb
tax
doopen: txa
;brk
pha
jsr clriocb
pla
tax
lda #<scrdev
sta ICBAL,x
lda #>scrdev
sta ICBAH,x
lda #OPEN
sta ICCOM,x
lda tmp1 ; get requested graphics mode
and #15
sta ICAX2,x
lda tmp1
and #$30
eor #$10
ora #12
sta ICAX1,x
jsr CIOV
bmi cioerr
lda tmp2 ; get fd
ldx #0
stx __oserror
rts
cioerr: sty tmp3 ; remember error code
lda #CLOSE
sta ICCOM,x
jsr CIOV ; close IOCB again since open failed
jsr fddecusage ; and decrement usage counter of fd
lda tmp3 ; put error code into A
jmp __mappederrno
.endproc ; __graphics
|
