cc65/libsrc/cbm610/cpeekrevers.s

30 lines
637 B
ArmAsm

;
; 2016-02-28, Groepaz
; 2017-06-19, Greg King
;
; unsigned char cpeekrevers (void);
;
.export _cpeekrevers
.import plot
.import CURS_X: zp, CharPtr: zp
.include "cbm610.inc"
_cpeekrevers:
ldx IndReg
ldy #$0F
sty IndReg
ldy CURS_X
lda (CharPtr),y ; get char from system bank
stx IndReg
ldx #>$0000
and #$80 ; get reverse bit
asl a
tax ; ldx #>$0000
rol a ; return boolean value
rts