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cc65/libsrc/atmos/cclear.s
cuz 9f547a5a4d Add basic support for ORIC Atmos
git-svn-id: svn://svn.cc65.org/cc65/trunk@2046 b7a2c559-68d2-44c3-8de9-860c34a00d81
2003-04-13 22:12:09 +00:00

39 lines
1004 B
ArmAsm

;
; Ullrich von Bassewitz, 2003-04-13
;
; void cclearxy (unsigned char x, unsigned char y, unsigned char length);
; void cclear (unsigned char length);
;
.export _cclearxy, _cclear
.import setscrptr
.import rvs
.import popax
.importzp ptr2
.include "atmos.inc"
_cclearxy:
pha ; Save the length
jsr popax ; Get X and Y
sta CURS_Y ; Store Y
stx CURS_X ; Store X
pla ; Restore the length and run into _cclear
_cclear:
tax ; Is the length zero?
beq @L9 ; Jump if done
jsr setscrptr ; Set ptr2 to screen, won't use X
lda #' '
ora rvs
@L1: sta (ptr2),y ; Write one char
iny ; Next char
bne @L2
inc ptr2+1 ; Bump high byte of screen pointer
@L2: dex
bne @L1
@L9: rts