;
-; Christian Groessler, December 2000
+; Christian Groessler, June 2004
;
; this file provides an equivalent to the BASIC GRAPHICS function
;
-; void __fastcall__ graphics(unsigned char mode);
+; int __fastcall__ _graphics(unsigned char mode);
+;
+;
- .export _graphics
- .constructor initscrmem,28
+ .export __graphics
- .import __graphmode_used
+ .import findfreeiocb
+ .import __do_oserror,__oserror
+ .import fddecusage
+ .import clriocb
+ .import fdtoiocb
+ .import newfd
+ .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: jsr fddecusage ; decrement usage counter of fd as open failed
+ jmp __do_oserror
+
+.endproc ; __graphics
-.proc _graphics
-
- rts ; not implemented yet!
-
-.endproc
-
-
-; calc. upper memory limit to use
-
-.proc initscrmem
-
- lda __graphmode_used
- beq ignore ; mode 0 doesn't need adjustment
- cmp #32
- bcs ignore ; invalid value
-
- asl a
- tay
- lda APPMHI
- sec
- sbc grmemusage,y
- sta APPMHI
- lda APPMHI+1
- sbc grmemusage+1,y
- sta APPMHI+1
-ignore: rts
-
-.endproc
.rodata
-; memory usage of the different graphics modes (0-31)
-; values < 0 of "bytes needed" are mappped to 0
-; bytes needed ; mode ; val. of MEMTOP
-grmemusage:
- .word 0 ; 0 ; 39967
- .word 0 ;-318 ; 1 ; 40285
- .word 0 ;-568 ; 2 ; 40535
- .word 0 ;-558 ; 3 ; 40525
- .word 0 ;-298 ; 4 ; 40265
- .word 182 ; 5 ; 39785
- .word 1182 ; 6 ; 38785
- .word 3198 ; 7 ; 36769
- .word 7120 ; 8 ; 32847
- .word 7146 ; 9 ; 32821
- .word 7146 ; 10 ; 32821
- .word 7146 ; 11 ; 32821
- .word 162 ; 12 ; 39805
- .word 0 ;-328 ; 13 ; 40295
- .word 3278 ; 14 ; 36689
- .word 7120 ; 15 ; 32847
- .word 0 ; 16 ; 39967
- .word 0 ;-320 ; 17 ; 40287
- .word 0 ;-572 ; 18 ; 40539
- .word 0 ;-560 ; 19 ; 40527
- .word 0 ;-296 ; 20 ; 40263
- .word 184 ; 21 ; 39783
- .word 1192 ; 22 ; 38775
- .word 3208 ; 23 ; 36759
- .word 7146 ; 24 ; 32821
- .word 7146 ; 25 ; 32821
- .word 7146 ; 26 ; 32821
- .word 7146 ; 27 ; 32821
- .word 160 ; 28 ; 39807
- .word 0 ;-332 ; 29 ; 40299
- .word 3304 ; 30 ; 36663
- .word 7146 ; 31 ; 32821
-
-; the program used to get these values (Atari BASIC):
-; 100 FILE=0
-; 110 IF FILE=1 THEN OPEN #1,8,0,"D:FREEMEM.OUT"
-; 120 IF FILE<>1 THEN OPEN #1,8,0,"E:"
-; 200 DIM G(32)
-; 210 FOR I=0 TO 32:GRAPHICS I:GOSUB 1000:G(I)=VAL:NEXT I
-; 220 GRAPHICS 0
-; 230 FOR I=0 TO 31:PRINT #1;I;":",G(I);" - ";G(0)-G(I):NEXT I
-; 240 CLOSE #1
-; 999 END
-; 1000 VAL=PEEK(741)+256*PEEK(742)
-; 1010 RETURN
-
+scrdev: .byte "S:", 0