75 lines
1.9 KiB
ArmAsm
75 lines
1.9 KiB
ArmAsm
;=============================================
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; put_sprite_no_transparency
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;=============================================
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; Sprite to display in INH,INL
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; Location is XPOS,YPOS
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; Note, only works if YPOS is multiple of two
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; time= 28 + Y* (34+ X*31 + 17) + 5
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; = 33 + Y*(51+31*X)
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put_sprite_no_transparency:
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ldy #0 ; byte 0 is xsize ; 2
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lda (INL),Y ; 5
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sta CH ; xsize is in CH ; 3
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iny ; 2
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lda (INL),Y ; byte 1 is ysize ; 5
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sta CV ; ysize is in CV ; 3
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iny ; Y now points to begin of sprite data ; 2
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lda YPOS ; make a copy of ypos ; 3
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sta TEMPY ; as we modify it ; 3
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;===========
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; 28
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put_sprite_loop:
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sty TEMP ; save sprite pointer ; 3
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ldy TEMPY ; get YPOS ; 3
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lda gr_offsets,Y ; lookup low-res memory address ; 4
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clc ; 2
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adc XPOS ; add in xpos ; 3
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sta OUTL ; store out low byte of addy ; 3
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lda gr_offsets+1,Y ; look up high byte ; 4
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adc DRAW_PAGE ; ; 3
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sta OUTH ; and store it out ; 3
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ldy TEMP ; restore sprite pointer ; 3
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; OUTH:OUTL now points at right place
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ldx CH ; load xsize into x ; 3
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;===========
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; 34
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put_sprite_pixel:
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lda (INL),Y ; get sprite colors ; 5
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iny ; increment sprite pointer ; 2
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sty TEMP ; save sprite pointer ; 3
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ldy #0 ; set out pointer ; 2
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sta (OUTL),Y ; and write it out ; 6
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;============
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; 18
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ldy TEMP ; restore sprite pointer ; 3
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inc OUTL ; increment output pointer ; 5
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dex ; decrement x counter ; 2
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bne put_sprite_pixel ; if not done, keep looping ; 3
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;==============
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; 13
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; -1
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inc TEMPY ; each line has two y vars ; 5
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inc TEMPY ; 5
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dec CV ; decemenet total y count ; 5
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bne put_sprite_loop ; loop if not done ; 3
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;==============
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; 17
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; -1
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rts ; return ; 6
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put_sprite_end:
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.assert >put_sprite_no_transparency = >put_sprite_end, error, "put_sprite crosses page"
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