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cc65/libsrc/geos-cbm/system/get_ostype.s
ol.sc baa6c53dec Normalized coding style.
git-svn-id: svn://svn.cc65.org/cc65/trunk@5494 b7a2c559-68d2-44c3-8de9-860c34a00d81
2012-02-07 22:37:13 +00:00

94 lines
1.6 KiB
ArmAsm

;
; Maciej 'YTM/Elysium' Witkowiak
;
; 10.09.2001
;
; Plus4 and GEOS 1.1 detection by
; Marco van den Heuvel, 2010-02-02
;
; unsigned char get_ostype (void);
; unsigned char get_tv (void);
.export _get_ostype
.export _get_tv
.importzp tmp1
.include "const.inc"
.include "geossym.inc"
.include "geossym2.inc"
_get_ostype:
ldx #0
lda version
cmp #$a9
beq geos11
and #%11110000
cmp #$10
beq geos10
lda c128Flag ; we're on at least 2.0
cmp #$18
beq geos_on_plus4
ora version
rts
geos10:
lda version
rts
geos11:
lda #$11
rts
geos_on_plus4:
lda #$04
rts
_get_tv:
jsr _get_ostype
cmp #$04
beq plus4_get_tv
bpl only40 ; C64 with 40 columns only
lda graphMode
bpl only40 ; C128 but currently on 40 columns
ldx #1 ; COLUMNS80
bne tvmode
only40: ldx #0 ; COLUMNS40
tvmode: ; PAL/NTSC check here, result in A
php
sei ; disable interrupts
lda CPU_DATA ; this is for C64
pha
lda #IO_IN ; enable access to I/O
sta CPU_DATA
bit rasreg
bpl tvmode ; wait for rasterline 127<x<256
lda #24 ; (rasterline now >=256!)
modelp:
cmp rasreg ; wait for rasterline = 24 (or 280 on PAL)
bne modelp
lda grcntrl1 ; 24 or 280 ?
bpl ntsc
lda #0 ; PAL
beq modeend
ntsc:
lda #$80 ; NTSC
modeend:
stx tmp1
ora tmp1
sta tmp1
ldx #0
pla
sta CPU_DATA ; restore memory config
plp ; restore interrupt state
lda tmp1
rts
plus4_get_tv:
ldx #1 ; Assume PAL
bit $FF07 ; Test bit 6
bvc plus4pal
dex ; NTSC
plus4pal:
txa
ldx #0
rts