1
0
mirror of https://github.com/cc65/cc65.git synced 2024-07-06 13:29:01 +00:00
cc65/libsrc/geos/system/get_ostype.s
izydorst 35f403b702 interrupt flag is cleared/restored rather than cleared/set
git-svn-id: svn://svn.cc65.org/cc65/trunk@890 b7a2c559-68d2-44c3-8de9-860c34a00d81
2001-09-10 22:11:19 +00:00

55 lines
1.2 KiB
ArmAsm

;
; Maciej 'YTM/Elysium' Witkowiak
;
; 10.09.2001
; unsigned char get_ostype (void);
; unsigned char get_tv (void);
.export get_ostype
.export get_tv
.import tmp1
.include "../inc/geossym.inc"
.include "../inc/geossym2.inc"
get_ostype:
lda version
and #%11110000
cmp #$10
beq geos10
lda c128Flag ; we're on at least 2.0
ora version
rts
geos10:
lda version
rts
get_tv:
jsr get_ostype
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
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
plp ; restore interrupt state
rts