133 lines
3.9 KiB
NASM
133 lines
3.9 KiB
NASM
;----------------------------------------------------------------------------------
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; Draw regular blitter line
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;
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; The routine will exit with the blitter active
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;
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; in d0.w x0
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; d1.w y0
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; d2.w x1
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; d3.w y1
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; d4.w bytes per row in bitplane
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; a0 bitplane
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; a5 $dff000
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; a0/d0-d5 trashed
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blb_blitter_line_init_bq:
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ADD_TO_BLITTER_QUEUE a4,a0
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clr.l (a4)+
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lea .bq_init(pc),a0
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move.l a0,(a4)+
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move.w d4,(a4)+
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rts
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.bq_init
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PUTMSG 50,<"Line Init">
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moveq.l #-1,d0
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move.w #BLTCON1F_LINE,bltcon1(a5)
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move.w #$8000,bltadat(a5)
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move.l d0,bltafwm(a5)
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move.w d0,bltbdat(a5)
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move.w (a0)+,bltcmod(a5)
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BLTHOGON
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moveq.l #0,d0
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rts
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;----------------------------------------------------------------------------------
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; Draw regular blitter line to blitter queue
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;
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; in d0.w x0
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; d1.w y0
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; d2.w x1
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; d3.w y1
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; d4.w bytes per row in bitplane
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; a0 bitplane
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; a4 blitterqueue struct
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blb_draw_blitter_line_bq:
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cmp.w d1,d3
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bge.s .downward
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exg d0,d2
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exg d1,d3
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.downward
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mulu d1,d4
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lea (a0,d4.w),a1
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moveq.l #-16,d4
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and.w d0,d4
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lsr.w #3,d4
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adda.w d4,a1
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moveq.l #15,d4
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and.w d0,d4
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ror.w #4,d4
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or.w d5,d4
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or.w #BLTCON0F_USEA|BLTCON0F_USEC|BLTCON0F_USED,d4
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swap d4
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sub.w d0,d2
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bpl.s .positiveDX
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neg.w d2
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addq.w #1,d4
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.positiveDX
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sub.w d1,d3
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cmp.w d2,d3
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bls.s .absDyLessThanAbsDx
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exg d2,d3
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addq.w #4,d4
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.absDyLessThanAbsDx
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move.b .octants(pc,d4.w),d4
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add.w d3,d3 ; 2 * dy
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move.w d3,d5
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sub.w d2,d5 ; 2 * dy - dx
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bpl.s .positiveGradient
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or.w #BLTCON1F_SIGN,d4
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.positiveGradient
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add.w d5,d5 ; 4 * dy - 2 * dx
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add.w d2,d2 ; 2 * dx
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add.w d2,d2 ; 4 * dx
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add.w d3,d3 ; 4 * dy
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move.w d3,d0
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sub.w d2,d3 ; 4 * (dy - dx)
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addq.w #4,d2 ; extra word height
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lsl.w #4,d2
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addq.w #2,d2 ; width == 2
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moveq.l #0,d1
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move.l a4,a0
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move.l d1,(a4)+
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move.l #.bq_routine,(a4)+
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move.l d4,(a4)+ ; bql_BltCon01
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move.l a1,(a4)+ ; bql_BltCPt
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move.w d0,(a4)+ ; bql_BltBMod, 4 * dy
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move.w d3,(a4)+ ; bql_BltAMod, 4 * (dy - dx)
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move.w d5,(a4)+ ; bql_BltAPtLo, 4 * dy - 2 * dx
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;move.l #blitter_temp_output_word,(a4)+ ; bql_BltDPt
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move.l a1,(a4)+ ; bql_BltDPt
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move.w d2,(a4)+ ; bql_BltSize
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CALLFW AddToBlitterQueue
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rts
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.octants
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dc.b BLTCON1F_LINE|BLTCON1F_SUD ; octant 7
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dc.b BLTCON1F_LINE|BLTCON1F_SUD|BLTCON1F_AUL ; octant 4
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dc.b BLTCON1F_LINE|BLTCON1F_SUD|BLTCON1F_SUL ; octant 0
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dc.b BLTCON1F_LINE|BLTCON1F_SUD|BLTCON1F_SUL|BLTCON1F_AUL ; octant 3
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dc.b BLTCON1F_LINE|0 ; octant 6
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dc.b BLTCON1F_LINE|BLTCON1F_SUL ; octant 5
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dc.b BLTCON1F_LINE|BLTCON1F_AUL ; octant 1
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dc.b BLTCON1F_LINE|BLTCON1F_SUL|BLTCON1F_AUL ; octant 2
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even
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.bq_routine
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PUTMSG 50,<"LineDraw %p">,a0
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move.l (a0)+,bltcon0(a5)
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move.l (a0)+,bltcpt(a5)
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move.l (a0)+,bltbmod(a5)
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move.l (a0)+,bltapt+2(a5)
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move.l (a0)+,bltdpt+2(a5)
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rts
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