cc65/libsrc/pce/cpeekrevers.s

27 lines
624 B
ArmAsm

;
; 2020-07-14, Groepaz
;
; unsigned char cpeekrevers (void);
;
; get inverse flag from current position, do NOT advance cursor
.export _cpeekrevers
.include "pce.inc"
.include "extzp.inc"
_cpeekrevers:
st0 #VDC_MARR ; Memory-Address Read
ldy SCREEN_PTR
ldx SCREEN_PTR+1
sty VDC_DATA_LO
stx VDC_DATA_HI
st0 #VDC_VRR ; VRAM Read Register
lda VDC_DATA_LO ; character (bit 7 is revers bit)
rol a
rol a
and #1
ldx #0
rts