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