51 lines
802 B
Plaintext
51 lines
802 B
Plaintext
|
|
.include "vcs-ca65.inc"
|
|
|
|
.global _set_horiz_pos
|
|
.export _reset_gfx
|
|
.export _reset_sprites
|
|
.export Return
|
|
|
|
;;;
|
|
|
|
; SetHorizPos routine
|
|
; A = X coordinate
|
|
; X = player number (0 or 1)
|
|
; must be in rodata segment because of alignment
|
|
.rodata
|
|
.align $10
|
|
.proc _set_horiz_pos
|
|
sec ; set carry flag
|
|
sta WSYNC ; start a new line
|
|
:
|
|
sbc #15 ; subtract 15
|
|
bcs :- ; branch until negative
|
|
eor #7 ; calculate fine offset
|
|
asl
|
|
asl
|
|
asl
|
|
asl
|
|
sta HMP0,x ; set fine offset
|
|
sta RESP0,x ; fix coarse position
|
|
sta WSYNC ; won't overrun if X < 150
|
|
rts
|
|
.endproc
|
|
.code
|
|
|
|
;;;
|
|
|
|
_reset_gfx:
|
|
lda #0
|
|
sta PF0
|
|
sta PF1
|
|
sta PF2
|
|
_reset_sprites:
|
|
lda #0
|
|
sta GRP0
|
|
sta GRP1
|
|
sta GRP0
|
|
sta GRP1
|
|
Return:
|
|
rts
|
|
|