2019-09-27 07:38:51 +00:00
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;
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2019-11-16 18:11:40 +00:00
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; 2019-11-06, Greg King
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2019-09-27 07:38:51 +00:00
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;
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2019-11-16 18:11:40 +00:00
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; /* Video mode defines */
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; #define VIDEOMODE_40x30 0x00
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; #define VIDEOMODE_80x60 0x02
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; #define VIDEOMODE_320x240 0x80
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; #define VIDEOMODE_SWAP (-1)
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;
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; signed char __fastcall__ videomode (signed char Mode);
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; /* Set the video mode, return the old mode.
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; ** Return -1 if Mode isn't valid.
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; ** Call with one of the VIDEOMODE_xx constants.
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; */
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2019-09-27 07:38:51 +00:00
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;
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.export _videomode
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2019-11-16 18:11:40 +00:00
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.import SCRMOD
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2019-09-27 07:38:51 +00:00
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.proc _videomode
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2019-11-16 18:11:40 +00:00
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tax
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clc ; (Get old mode)
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jsr SCRMOD
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pha
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txa
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sec ; (Set new mode)
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jsr SCRMOD
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pla ; Get back old mode
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bcs @L1
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ldx #>$0000 ; Clear high byte
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rts
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2019-09-27 07:38:51 +00:00
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2019-11-16 18:11:40 +00:00
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; The new mode is invalid. Go back to the old mode. Return -1.
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2019-09-27 07:38:51 +00:00
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2019-11-16 18:11:40 +00:00
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@L1: sec
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jsr SCRMOD
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lda #<-1
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tax
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2019-09-27 07:38:51 +00:00
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rts
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.endproc
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