* * Copyright (C) 1996-1997 Id Software, Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. * * See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * ** ** Quake for AMIGA ** d_sky.c assembler implementations by Frank Wille ** XREF _d_viewbuffer XREF _screenwidth XREF _r_refdef XREF _r_skysource XREF _vid XREF _vright XREF _vpn XREF _vup XREF _skytime XREF _skyspeed XDEF _D_DrawSkyScans8 PSPAN_NEXT = $C REFDEF_VRECT_X = 0 REFDEF_VRECT_Y = 4 REFDEF_VRECT_WIDTH = 8 REFDEF_VRECT_HEIGHT = 12 VID_WIDTH = 20 VID_HEIGHT = 24 SKYSHIFT = 7 SKYSIZE = (1 << SKYSHIFT) SKYMASK = (SKYSIZE - 1) SKY_SPAN_SHIFT = 5 SKY_SPAN_MAX = (1 << SKY_SPAN_SHIFT) R_SKY_SMASK = $007f R_SKY_TMASK = $007f ****************************************************************************** * * void D_DrawSkyScans8 (espan_t *pspan) * * standard scan drawing function for the sky * * D_Sky_uv_To_st is inlined. * * IMPORTANT!! SKY_SPAN_SHIFT must *NOT* exceed 5 (The ReciprocTable * has to be extended) * ****************************************************************************** cnop 0,4 _D_DrawSkyScans8 ***** stackframe rsreset .savefp1 rs.x 1 .saved4 rs.l 1 .saved5 rs.l 1 .vr0 rs.s 1 .vr1 rs.s 1 .vr2 rs.s 1 .fpuregs rs.x 6 .intregs rs.l 11 rs.l 1 .pspan rs.l 1 ****** Prologue. Global variables are put into registers or onto the stackframe movem.l d2-d7/a2-a6,-(sp) fmovem.x fp2-fp7,-(sp) sub.l #.fpuregs,sp ****** First loop. In every iteration one complete span is drawn move.l .pspan(sp),a6 ;get function parameter lea _r_refdef,a1 move.l REFDEF_VRECT_HEIGHT(a1),d0 move.l REFDEF_VRECT_WIDTH(a1),d1 cmp.l d0,d1 ;if (r_refdef.vrect.width >= r_...) blt.b .height fmove.l d1,fp0 ;temp = (float)r_refdef.vrect.height bra.b .width .height fmove.l d0,fp0 ;temp = (float)r_refdef.vrect.width .width fmove.s #8192,fp1 fdiv fp0,fp1 ;fp1 = 8192 / temp move.l _r_skysource,a5 .loop fmove.x fp1,.savefp1(sp) move.l _d_viewbuffer,a0 move.l _screenwidth,d0 move.l (a6)+,d3 move.l (a6)+,d2 fmove.l d2,fp4 muls d2,d0 ;d0 = screenwidth * pspan->v add.l d3,d0 add.l d0,a0 ;pdest = d_viewbuffer + pspan->u + d0 fmove.s #4096,fp7 lea _vpn,a2 fmove.s (a2)+,fp5 fmul fp7,fp5 ;fp5 = 4096*vpn[0] fmove.s (a2)+,fp6 fmul fp7,fp6 ;fp6 = 4096*vpn[1] fmul.s (a2)+,fp7 ;fp7 = 4096*vpn[2] lea _vid,a1 move.l VID_WIDTH(a1),d0 move.l VID_HEIGHT(a1),d1 asr.l #1,d0 move.l d0,a2 ;a2 = vid.width>>1 asr.l #1,d1 fmove.l d1,fp0 fsub fp4,fp0 ;fp0 = ((vid.height>>1)-v) fmul fp1,fp0 ;wv = 8192 * fp0 / temp lea _vup,a1 fmove.s (a1)+,fp2 fmul fp0,fp2 ;fp2 = wv*vup[0] fadd fp2,fp5 ;fp5 = 4096*vpn[0] + wv*vup[0] fmove.s (a1)+,fp3 fmul fp0,fp3 ;fp3 = wv*vup[1] fadd fp3,fp6 ;fp6 = 4096*vpn[1] + wv*vup[0] fmul.s (a1)+,fp0 ;fp0 = wv*vup[2] fadd fp0,fp7 ;fp7 = 4096*vpn[2] + wv*vup[2] lea _vright,a1 fmove.s (a1)+,fp2 fmove.s (a1)+,fp3 fmove.s (a1)+,fp4 fmul fp1,fp2 ;fp2 = 8192 * vright[0] / temp fmul fp1,fp3 ;fp3 = 8192 * vright[1] / temp fmul fp1,fp4 ;fp4 = 8192 * vright[2] / temp fmove.s fp2,.vr0(sp) fmove.s fp3,.vr1(sp) fmove.s #3,fp1 fmul fp1,fp7 ;multiply by 3 fmul fp1,fp4 fmove.s fp4,.vr2(sp) move.l (a6)+,d1 ;count = pspan->count fmove.s _skytime,fp0 fmul.s _skyspeed,fp0 fmul.s #65536,fp0 fmove.l fp0,d0 ;d0 = skytime*skyspeed*$10000 move.l d0,a4 ****** D_Sky_uv_To_st (inlined) move.l d3,d0 sub.l a2,d0 fmove.l d0,fp0 ;fp0 = (float(u-(vid.width>>1))) fmove fp0,fp2 fmul.s .vr0(sp),fp2 ;fp2 = wu*vright[0] fadd fp5,fp2 ;fp2 = end[0] fmove fp2,fp1 fmul fp2,fp2 fmove fp0,fp3 fmul.s .vr1(sp),fp3 ;fp3 = wu*vright[1] fadd fp6,fp3 ;fp3 = end[1] fmove fp3,fp4 fmul fp3,fp3 fadd fp3,fp2 fmul.s .vr2(sp),fp0 ;fp0 = wu*vright[2] fadd fp7,fp0 ;fp0 = end[2] fmul fp0,fp0 fadd fp0,fp2 fsqrt fp2 ;fp2 = length(end) fmove.s #(65536*6*(SKYSIZE/2-1)),fp0 fdiv fp2,fp0 fmul fp0,fp1 ;fp1 = 6*(SKYSIZE/2-1)*end[0] fmul fp0,fp4 ;fp4 = 6*(SKYSIZE/2-1)*end[1] fmove.l fp1,d6 add.l a4,d6 ;d6 = s fmove.l fp4,d7 add.l a4,d7 ;d7 = t ****** end of D_Sky_uv_To_st ****** Second loop. In every iteration one part of the whole span is drawn ****** d2 gets the value (spancount-1)! [NOT spancount] ****** d1 = count * do * { * if (count >= SKY_SPAN_MAX) * spancount = SKY_SPAN_MAX; * else * spancount = count; * * count -= spancount; * * if (count) * { .loop2 move.l #SKY_SPAN_MAX-1,d2 ;spancount = SKY_SPAN_MAX cmp.l #SKY_SPAN_MAX,d1 ;if (count >= SKY_SPAN_MAX) bgt.b .cont move.l d1,d2 ;spancount = count subq.l #1,d2 moveq #0,d1 ;count -= spancount bra.w .finalpart .cont sub.l #SKY_SPAN_MAX,d1 ;count -= spancount; ****** Evaluation of the values for the inner loop. This version is used for ****** span size = SKY_SPAN_MAX * // calculate s and t at far end of span, * // calculate s and t steps across span by shifting * u += spancount; * * D_Sky_uv_To_st (u, v, &snext, &tnext); * * sstep = (snext - s) >> SKY_SPAN_SHIFT; * tstep = (tnext - t) >> SKY_SPAN_SHIFT; * } add.l d2,d3 addq.l #1,d3 ****** D_Sky_uv_To_st (inlined) move.l d3,d0 sub.l a2,d0 fmove.l d0,fp0 ;fp0 = (float(u-(vid.width>>1))) fmove fp0,fp2 fmul.s .vr0(sp),fp2 ;fp2 = wu*vright[0] fadd fp5,fp2 ;fp2 = end[0] fmove fp2,fp1 fmul fp2,fp2 fmove fp0,fp3 fmul.s .vr1(sp),fp3 ;fp3 = wu*vright[1] fadd fp6,fp3 ;fp3 = end[1] fmove fp3,fp4 fmul fp3,fp3 fadd fp3,fp2 fmul.s .vr2(sp),fp0 ;fp0 = wu*vright[2] fadd fp7,fp0 ;fp0 = end[2] fmul fp0,fp0 fadd fp0,fp2 fsqrt fp2 ;fp2 = length(end) fmove.s #(65536*6*(SKYSIZE/2-1)),fp0 fdiv fp2,fp0 fmul fp0,fp1 ;fp1 = 6*(SKYSIZE/2-1)*end[0] fmul fp0,fp4 ;fp4 = 6*(SKYSIZE/2-1)*end[1] fmove.l fp1,d4 add.l a4,d4 ;d6 = snext fmove.l fp4,d5 add.l a4,d5 ;d7 = tnext ****** end of D_Sky_uv_To_st move.l d4,.saved4(sp) ;save snext move.l d5,.saved5(sp) ;save tnext sub.l d6,d4 ;d4 = snext - s sub.l d7,d5 ;d5 = tnext - t asr.l #SKY_SPAN_SHIFT,d4 ;sstep = d4 >> SKY_SPAN_SHIFT asr.l #SKY_SPAN_SHIFT,d5 ;tstep = d5 >> SKY_SPAN_SHIFT bra.w .mainloop .finalpart add.l d2,d3 ****** D_Sky_uv_To_st (inlined) move.l d3,d0 sub.l a2,d0 fmove.l d0,fp0 ;fp0 = (float(u-(vid.width>>1))) fmove fp0,fp2 fmul.s .vr0(sp),fp2 ;fp2 = wu*vright[0] fadd fp5,fp2 ;fp2 = end[0] fmove fp2,fp1 fmul fp2,fp2 fmove fp0,fp3 fmul.s .vr1(sp),fp3 ;fp3 = wu*vright[1] fadd fp6,fp3 ;fp3 = end[1] fmove fp3,fp4 fmul fp3,fp3 fadd fp3,fp2 fmul.s .vr2(sp),fp0 ;fp0 = wu*vright[2] fadd fp7,fp0 ;fp0 = end[2] fmul fp0,fp0 fadd fp0,fp2 fsqrt fp2 ;fp2 = length(end) fmove.s #(65536*6*(SKYSIZE/2-1)),fp0 fdiv fp2,fp0 fmul fp0,fp1 ;fp1 = 6*(SKYSIZE/2-1)*end[0] fmul fp0,fp4 ;fp4 = 6*(SKYSIZE/2-1)*end[1] fmove.l fp1,d4 add.l a4,d4 ;d6 = snext fmove.l fp4,d5 add.l a4,d5 ;d7 = tnext ****** end of D_Sky_uv_To_st move.l d4,.saved4(sp) ;save snext move.l d5,.saved5(sp) ;save tnext sub.l d6,d4 ;d4 = snext - s sub.l d7,d5 ;d5 = tnext - t cmp #5,d2 ;(spancount-1) < 5? blt.b .special ;yes -> special case .qdiv asr.l #7,d4 ;d4 >> 7 asr.l #7,d5 ;d5 >> 7 lea ReciprocTable,a3 ;a3 -> reciprocal table move 0(a3,d2.w*2),d0 ;d0 = (1/(spancount-1))<<16 muls d0,d4 ;d4 = d4 / (spancount-1) asr.l #7,d4 ;sstep = d4 >> 7 muls d0,d5 ;d5 = d5 / (spancount-1) asr.l #7,d5 ;tstep = d5 >> 7 bra.b .mainloop .special cmp #1,d2 ;switch (spancount-1) ble.b .mainloop ;0,1 -> no scaling needed cmp #3,d2 ;3 -> standard qdiv beq.b .qdiv blt.b .spec_2 asr.l #2,d4 ;4 -> scale by shifting right asr.l #2,d5 bra.b .mainloop .spec_2 asr.l #1,d4 ;2 -> scale by shifting right asr.l #1,d5 ****** Main drawing loop. ****** d2 : spancount ****** d4 : sstep ****** d5 : tstep ****** d6 : s ****** d7 : t ****** a0 : pdest ****** a5 : r_skysource * do * { * *pdest++ = r_skysource[((t & R_SKY_TMASK) >> 8) + * ((s & R_SKY_SMASK) >> 16)]; * s += sstep; * t += tstep; * } while (--spancount > 0); .mainloop move.l d1,-(sp) swap d4 swap d5 swap d6 swap d7 move d5,d1 ;d2 = tstep integer part move d4,d0 ;d0 = sstep integer part clr d5 ;d5 = tstep fractional part clr d4 ;d4 = sstep fractional part .loop3 and #R_SKY_TMASK,d7 asl #8,d7 lea 0(a5,d7.w),a3 asr #8,d7 and #R_SKY_SMASK,d6 move.b 0(a3,d6.w),(a0)+ add.l d4,d6 addx.w d0,d6 add.l d5,d7 addx.w d1,d7 dbra d2,.loop3 move.l (sp)+,d1 ****** loop terminations move.l .saved5(sp),d7 ;t = tnext move.l .saved4(sp),d6 ;s = snext tst.l d1 ;while (count > 0) bgt.w .loop2 fmove.x .savefp1(sp),fp1 move.l (a6)+,a6 tst.l a6 bne.w .loop add.l #.fpuregs,sp fmovem.x (sp)+,fp2-fp7 movem.l (sp)+,d2-d7/a2-a6 rts ReciprocTable dc.w 0 dc.w 0 dc.w 0 dc.w 16384/3 dc.w 0 dc.w 16384/5 dc.w 16384/6 dc.w 16384/7 dc.w 16384/8 dc.w 16384/9 dc.w 16384/10 dc.w 16384/11 dc.w 16384/12 dc.w 16384/13 dc.w 16384/14 dc.w 16384/15 dc.w 16384/16 dc.w 16384/17 dc.w 16384/18 dc.w 16384/19 dc.w 16384/20 dc.w 16384/21 dc.w 16384/22 dc.w 16384/23 dc.w 16384/24 dc.w 16384/25 dc.w 16384/26 dc.w 16384/27 dc.w 16384/28 dc.w 16384/29 dc.w 16384/30 dc.w 16384/31