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cc65/libsrc/cx16/cpeekrevers.s

33 lines
937 B
ArmAsm

;
; 2016-02-28, Groepaz
; 2019-09-25, Greg King
;
; unsigned char cpeekrevers (void);
; /* Return the reverse attribute from the current cursor position.
; ** If the character is reversed, then return 1; return 0 otherwise.
; */
;
.export _cpeekrevers
.include "cx16.inc"
_cpeekrevers:
php
sei ; don't let cursor blinking interfere
stz VERA::CTRL ; use port 0
lda CURS_Y
sta VERA::ADDR+1 ; set row number
stz VERA::ADDR+2
lda CURS_X ; get character column
asl a ; each character has two bytes
sta VERA::ADDR
lda VERA::DATA0 ; get screen code
plp
and #%10000000 ; get reverse bit
asl a
tax ; ldx #>$0000
rol a ; return boolean value
rts