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setcolor, getcolor and setcolor_low functions

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git-svn-id: svn://svn.cc65.org/cc65/trunk@93 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cpg 2000-06-22 00:42:26 +00:00
parent 564eed1a2d
commit 7198329ce3
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libsrc/atari/setcolor.s Normal file
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;
; Christian Groessler, June 2000
;
; this file provides a setcolor() function similar to BASIC SETCOLOR
;
; void __fastcall__ setcolor (unsigned char color_reg, unsigned char hue, unsigned char luminace);
; void __fastcall__ setcolor_low (unsigned char color_reg, unsigned char color_value);
; unsigned char __fastcall__ getcolor (unsigned char color_reg);
;
.export _setcolor, _setcolor_low, _getcolor
.import popa
.include "atari.inc"
.proc _getcolor
tax
lda COLOR0,x ; get current value
ldx #0
rts
.endproc
.proc _setcolor
; asl a ; not -> BASIC compatible
sta lum ; remember luminance
jsr popa ; get hue
asl a
asl a
asl a
asl a
ora lum
; jmp _setcolor_low
.endproc
.proc _setcolor_low
pha
jsr popa
tax
pla
sta COLOR0,x
rts
.endproc
.bss
lum: .res 1