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| ; c2p1x1_2_c5_gen | |
| IFND BPLX | |
| BPLX EQU 320 | |
| ENDC | |
| IFND BPLY | |
| BPLY EQU 256 | |
| ENDC | |
| IFND BPLSIZE | |
| BPLSIZE EQU BPLX*BPLY/8 | |
| ENDC | |
| IFND CHUNKYXMAX | |
| CHUNKYXMAX EQU BPLX | |
| ENDC | |
| IFND CHUNKYYMAX | |
| CHUNKYYMAX EQU BPLY | |
| ENDC | |
| section text,text | |
| ; d0.w chunkyx [chunky-pixels] | |
| ; d1.w chunkyy [chunky-pixels] | |
| ; d2.w (scroffsx) [screen-pixels] | |
| ; d3.w scroffsy [screen-pixels] | |
| ; d4.w (rowlen) [bytes] -- offset between one row and the next in a bpl | |
| ; d5.l (bplsize) [bytes] -- offset between one row in one bpl and the next bpl | |
| _c2p1x1_2_c5_gen_init:: | |
| movem.l d2-d3,-(sp) | |
| andi.l #$ffff,d0 | |
| mulu.w d0,d3 | |
| lsr.l #3,d3 | |
| move.l d3,c2p1x1_4_c5_gen_scroffs | |
| mulu.w d0,d1 | |
| move.l d1,c2p1x1_4_c5_gen_pixels | |
| movem.l (sp)+,d2-d3 | |
| rts | |
| ; a0 c2pscreen | |
| ; a1 bitplanes | |
| _c2p1x1_2_c5_gen:: | |
| movem.l d2-d7/a2-a6,-(sp) | |
| move.l #$00ff00ff,d4 | |
| move.l #$55555555,d5 | |
| add.l c2p1x1_4_c5_gen_scroffs,a1 | |
| move.l c2p1x1_4_c5_gen_pixels,a2 | |
| add.l a0,a2 | |
| cmp.l a0,a2 | |
| beq .none | |
| move.l (a0)+,d0 | |
| lsl.l #4,d0 | |
| or.l (a0)+,d0 | |
| move.l (a0)+,d1 | |
| lsl.l #4,d1 | |
| or.l (a0)+,d1 | |
| move.l (a0)+,d2 | |
| lsl.l #4,d2 | |
| or.l (a0)+,d2 | |
| move.l (a0)+,d3 | |
| lsl.l #4,d3 | |
| or.l (a0)+,d3 | |
| move.w d2,d6 | |
| move.w d3,d7 | |
| move.w d0,d2 | |
| move.w d1,d3 | |
| swap d2 | |
| swap d3 | |
| move.w d2,d0 | |
| move.w d3,d1 | |
| move.w d6,d2 | |
| move.w d7,d3 | |
| lsl.l #2,d0 | |
| lsl.l #2,d1 | |
| or.l d2,d0 | |
| or.l d3,d1 | |
| move.l d1,d7 | |
| lsr.l #8,d7 | |
| eor.l d0,d7 | |
| bra.s .start | |
| .x | |
| move.l (a0)+,d0 | |
| lsl.l #4,d0 | |
| or.l (a0)+,d0 | |
| move.l (a0)+,d1 | |
| lsl.l #4,d1 | |
| or.l (a0)+,d1 | |
| move.l (a0)+,d2 | |
| lsl.l #4,d2 | |
| or.l (a0)+,d2 | |
| move.l (a0)+,d3 | |
| lsl.l #4,d3 | |
| or.l (a0)+,d3 | |
| move.l a5,BPLSIZE(a1) | |
| move.w d2,d6 | |
| move.w d3,d7 | |
| move.w d0,d2 | |
| move.w d1,d3 | |
| swap d2 | |
| swap d3 | |
| move.w d2,d0 | |
| move.w d3,d1 | |
| move.w d6,d2 | |
| move.w d7,d3 | |
| lsl.l #2,d0 | |
| lsl.l #2,d1 | |
| or.l d2,d0 | |
| or.l d3,d1 | |
| move.l d1,d7 | |
| lsr.l #8,d7 | |
| eor.l d0,d7 | |
| move.l a6,(a1)+ | |
| .start | |
| and.l d4,d7 | |
| eor.l d7,d0 | |
| lsl.l #8,d7 | |
| eor.l d7,d1 | |
| move.l d1,d7 | |
| lsr.l #1,d7 | |
| eor.l d0,d7 | |
| and.l d5,d7 | |
| eor.l d7,d0 | |
| add.l d7,d7 | |
| eor.l d7,d1 | |
| move.l d0,a5 | |
| move.l d1,a6 | |
| cmpa.l a0,a2 | |
| bne.s .x | |
| move.l a5,BPLSIZE(a1) | |
| move.l a6,(a1)+ | |
| .none | |
| movem.l (sp)+,d2-d7/a2-a6 | |
| rts | |
| section bss,bss | |
| c2p1x1_4_c5_gen_scroffs ds.l 1 | |
| c2p1x1_4_c5_gen_pixels ds.l 1 |
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