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cc65/libsrc/cx16/bordercolor.s

28 lines
712 B
ArmAsm

;
; 2019-09-23, Greg King
;
; unsigned char __fastcall__ bordercolor (unsigned char color);
; /* Set the color for the border. The old color setting is returned. */
;
.export _bordercolor
.include "cx16.inc"
_bordercolor:
tax
; Point to the border color register.
stz VERA::CTRL ; Use port 0
lda #<VERA::COMPOSER::FRAME
sta VERA::ADDR
lda #>VERA::COMPOSER::FRAME
sta VERA::ADDR+1
ldy #^VERA::COMPOSER::FRAME | VERA::INC0
sty VERA::ADDR+2
lda VERA::DATA0 ; get old value
stx VERA::DATA0 ; set new value
rts