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cc65/libsrc/atmos/chline.s

42 lines
1.2 KiB
ArmAsm

;
; Ullrich von Bassewitz, 08.08.1998
;
; void chlinexy (unsigned char x, unsigned char y, unsigned char length);
; void chline (unsigned char length);
;
.export _chlinexy, _chline
.import setscrptr
.import rvs
.import popax
.importzp ptr2
.include "atmos.inc"
_chlinexy:
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 _chline
_chline:
tax ; Is the length zero?
beq @L9 ; Jump if done
jsr setscrptr ; Set ptr2 to screen, won't use X
txa ; Length into A
clc
adc CURS_X
sta CURS_X ; Correct X position by length
lda #'-' ; Horizontal line screen code
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