ref: 02611e064eceed8d8cda8cc4d6e60f8f1833ea72
dir: /u/d_spr8.s/
// // d_spr8.s // x86 assembly-language horizontal 8-bpp transparent span-drawing code. // #include "asm_i386.h" #include "quakeasm.h" #include "asm_draw.h" #ifdef id386 //---------------------------------------------------------------------- // 8-bpp horizontal span drawing code for polygons, with transparency. //---------------------------------------------------------------------- .text // out-of-line, rarely-needed clamping code LClampHigh0: movl C(bbextents),%esi jmp LClampReentry0 LClampHighOrLow0: jg LClampHigh0 xorl %esi,%esi jmp LClampReentry0 LClampHigh1: movl C(bbextentt),%edx jmp LClampReentry1 LClampHighOrLow1: jg LClampHigh1 xorl %edx,%edx jmp LClampReentry1 LClampLow2: movl $2048,%ebp jmp LClampReentry2 LClampHigh2: movl C(bbextents),%ebp jmp LClampReentry2 LClampLow3: movl $2048,%ecx jmp LClampReentry3 LClampHigh3: movl C(bbextentt),%ecx jmp LClampReentry3 LClampLow4: movl $2048,%eax jmp LClampReentry4 LClampHigh4: movl C(bbextents),%eax jmp LClampReentry4 LClampLow5: movl $2048,%ebx jmp LClampReentry5 LClampHigh5: movl C(bbextentt),%ebx jmp LClampReentry5 #define pspans 4+16 .align 4 .globl C(D_SpriteDrawSpans) C(D_SpriteDrawSpans): pushl %ebp // preserve caller's stack frame pushl %edi pushl %esi // preserve register variables pushl %ebx // // set up scaled-by-8 steps, for 8-long segments; also set up cacheblock // and span list pointers, and 1/z step in 0.32 fixed-point // // FIXME: any overlap from rearranging? flds C(d_sdivzstepu) fmuls fp_8 movl C(cacheblock),%edx flds C(d_tdivzstepu) fmuls fp_8 movl pspans(%esp),%ebx // point to the first span descriptor flds C(d_zistepu) fmuls fp_8 movl %edx,pbase // pbase = cacheblock flds C(d_zistepu) fmuls fp_64kx64k fxch %st(3) fstps sdivz8stepu fstps zi8stepu fstps tdivz8stepu fistpl izistep movl izistep,%eax rorl $16,%eax // put upper 16 bits in low word movl sspan_t_count(%ebx),%ecx movl %eax,izistep cmpl $0,%ecx jle LNextSpan LSpanLoop: // // set up the initial s/z, t/z, and 1/z on the FP stack, and generate the // initial s and t values // // FIXME: pipeline FILD? fildl sspan_t_v(%ebx) fildl sspan_t_u(%ebx) fld %st(1) // dv | du | dv fmuls C(d_sdivzstepv) // dv*d_sdivzstepv | du | dv fld %st(1) // du | dv*d_sdivzstepv | du | dv fmuls C(d_sdivzstepu) // du*d_sdivzstepu | dv*d_sdivzstepv | du | dv fld %st(2) // du | du*d_sdivzstepu | dv*d_sdivzstepv | du | dv fmuls C(d_tdivzstepu) // du*d_tdivzstepu | du*d_sdivzstepu | // dv*d_sdivzstepv | du | dv fxch %st(1) // du*d_sdivzstepu | du*d_tdivzstepu | // dv*d_sdivzstepv | du | dv faddp %st(0),%st(2) // du*d_tdivzstepu | // du*d_sdivzstepu + dv*d_sdivzstepv | du | dv fxch %st(1) // du*d_sdivzstepu + dv*d_sdivzstepv | // du*d_tdivzstepu | du | dv fld %st(3) // dv | du*d_sdivzstepu + dv*d_sdivzstepv | // du*d_tdivzstepu | du | dv fmuls C(d_tdivzstepv) // dv*d_tdivzstepv | // du*d_sdivzstepu + dv*d_sdivzstepv | // du*d_tdivzstepu | du | dv fxch %st(1) // du*d_sdivzstepu + dv*d_sdivzstepv | // dv*d_tdivzstepv | du*d_tdivzstepu | du | dv fadds C(d_sdivzorigin) // sdivz = d_sdivzorigin + dv*d_sdivzstepv + // du*d_sdivzstepu; stays in %st(2) at end fxch %st(4) // dv | dv*d_tdivzstepv | du*d_tdivzstepu | du | // s/z fmuls C(d_zistepv) // dv*d_zistepv | dv*d_tdivzstepv | // du*d_tdivzstepu | du | s/z fxch %st(1) // dv*d_tdivzstepv | dv*d_zistepv | // du*d_tdivzstepu | du | s/z faddp %st(0),%st(2) // dv*d_zistepv | // dv*d_tdivzstepv + du*d_tdivzstepu | du | s/z fxch %st(2) // du | dv*d_tdivzstepv + du*d_tdivzstepu | // dv*d_zistepv | s/z fmuls C(d_zistepu) // du*d_zistepu | // dv*d_tdivzstepv + du*d_tdivzstepu | // dv*d_zistepv | s/z fxch %st(1) // dv*d_tdivzstepv + du*d_tdivzstepu | // du*d_zistepu | dv*d_zistepv | s/z fadds C(d_tdivzorigin) // tdivz = d_tdivzorigin + dv*d_tdivzstepv + // du*d_tdivzstepu; stays in %st(1) at end fxch %st(2) // dv*d_zistepv | du*d_zistepu | t/z | s/z faddp %st(0),%st(1) // dv*d_zistepv + du*d_zistepu | t/z | s/z flds fp_64k // fp_64k | dv*d_zistepv + du*d_zistepu | t/z | s/z fxch %st(1) // dv*d_zistepv + du*d_zistepu | fp_64k | t/z | s/z fadds C(d_ziorigin) // zi = d_ziorigin + dv*d_zistepv + // du*d_zistepu; stays in %st(0) at end // 1/z | fp_64k | t/z | s/z fld %st(0) // FIXME: get rid of stall on FMUL? fmuls fp_64kx64k fxch %st(1) // // calculate and clamp s & t // fdivr %st(0),%st(2) // 1/z | z*64k | t/z | s/z fxch %st(1) fistpl izi // 0.32 fixed-point 1/z movl izi,%ebp // // set pz to point to the first z-buffer pixel in the span // rorl $16,%ebp // put upper 16 bits in low word movl sspan_t_v(%ebx),%eax movl %ebp,izi movl sspan_t_u(%ebx),%ebp imull C(d_zrowbytes) shll $1,%ebp // a word per pixel addl C(d_pzbuffer),%eax addl %ebp,%eax movl %eax,pz // // point %edi to the first pixel in the span // movl C(d_viewbuffer),%ebp movl sspan_t_v(%ebx),%eax pushl %ebx // preserve spans pointer movl C(tadjust),%edx movl C(sadjust),%esi movl C(d_scantable)(,%eax,4),%edi // v * screenwidth addl %ebp,%edi movl sspan_t_u(%ebx),%ebp addl %ebp,%edi // pdest = &pdestspan[scans->u]; // // now start the FDIV for the end of the span // cmpl $8,%ecx ja LSetupNotLast1 decl %ecx jz LCleanup1 // if only one pixel, no need to start an FDIV movl %ecx,spancountminus1 // finish up the s and t calcs fxch %st(1) // z*64k | 1/z | t/z | s/z fld %st(0) // z*64k | z*64k | 1/z | t/z | s/z fmul %st(4),%st(0) // s | z*64k | 1/z | t/z | s/z fxch %st(1) // z*64k | s | 1/z | t/z | s/z fmul %st(3),%st(0) // t | s | 1/z | t/z | s/z fxch %st(1) // s | t | 1/z | t/z | s/z fistpl s // 1/z | t | t/z | s/z fistpl t // 1/z | t/z | s/z fildl spancountminus1 flds C(d_tdivzstepu) // _d_tdivzstepu | spancountminus1 flds C(d_zistepu) // _d_zistepu | _d_tdivzstepu | spancountminus1 fmul %st(2),%st(0) // _d_zistepu*scm1 | _d_tdivzstepu | scm1 fxch %st(1) // _d_tdivzstepu | _d_zistepu*scm1 | scm1 fmul %st(2),%st(0) // _d_tdivzstepu*scm1 | _d_zistepu*scm1 | scm1 fxch %st(2) // scm1 | _d_zistepu*scm1 | _d_tdivzstepu*scm1 fmuls C(d_sdivzstepu) // _d_sdivzstepu*scm1 | _d_zistepu*scm1 | // _d_tdivzstepu*scm1 fxch %st(1) // _d_zistepu*scm1 | _d_sdivzstepu*scm1 | // _d_tdivzstepu*scm1 faddp %st(0),%st(3) // _d_sdivzstepu*scm1 | _d_tdivzstepu*scm1 fxch %st(1) // _d_tdivzstepu*scm1 | _d_sdivzstepu*scm1 faddp %st(0),%st(3) // _d_sdivzstepu*scm1 faddp %st(0),%st(3) flds fp_64k fdiv %st(1),%st(0) // this is what we've gone to all this trouble to // overlap jmp LFDIVInFlight1 LCleanup1: // finish up the s and t calcs fxch %st(1) // z*64k | 1/z | t/z | s/z fld %st(0) // z*64k | z*64k | 1/z | t/z | s/z fmul %st(4),%st(0) // s | z*64k | 1/z | t/z | s/z fxch %st(1) // z*64k | s | 1/z | t/z | s/z fmul %st(3),%st(0) // t | s | 1/z | t/z | s/z fxch %st(1) // s | t | 1/z | t/z | s/z fistpl s // 1/z | t | t/z | s/z fistpl t // 1/z | t/z | s/z jmp LFDIVInFlight1 .align 4 LSetupNotLast1: // finish up the s and t calcs fxch %st(1) // z*64k | 1/z | t/z | s/z fld %st(0) // z*64k | z*64k | 1/z | t/z | s/z fmul %st(4),%st(0) // s | z*64k | 1/z | t/z | s/z fxch %st(1) // z*64k | s | 1/z | t/z | s/z fmul %st(3),%st(0) // t | s | 1/z | t/z | s/z fxch %st(1) // s | t | 1/z | t/z | s/z fistpl s // 1/z | t | t/z | s/z fistpl t // 1/z | t/z | s/z fadds zi8stepu fxch %st(2) fadds sdivz8stepu fxch %st(2) flds tdivz8stepu faddp %st(0),%st(2) flds fp_64k fdiv %st(1),%st(0) // z = 1/1/z // this is what we've gone to all this trouble to // overlap LFDIVInFlight1: addl s,%esi addl t,%edx movl C(bbextents),%ebx movl C(bbextentt),%ebp cmpl %ebx,%esi ja LClampHighOrLow0 LClampReentry0: movl %esi,s movl pbase,%ebx shll $16,%esi cmpl %ebp,%edx movl %esi,sfracf ja LClampHighOrLow1 LClampReentry1: movl %edx,t movl s,%esi // sfrac = scans->sfrac; shll $16,%edx movl t,%eax // tfrac = scans->tfrac; sarl $16,%esi movl %edx,tfracf // // calculate the texture starting address // sarl $16,%eax addl %ebx,%esi imull C(cachewidth),%eax // (tfrac >> 16) * cachewidth addl %eax,%esi // psource = pbase + (sfrac >> 16) + // ((tfrac >> 16) * cachewidth); // // determine whether last span or not // cmpl $8,%ecx jna LLastSegment // // not the last segment; do full 8-wide segment // LNotLastSegment: // // advance s/z, t/z, and 1/z, and calculate s & t at end of span and steps to // get there // // pick up after the FDIV that was left in flight previously fld %st(0) // duplicate it fmul %st(4),%st(0) // s = s/z * z fxch %st(1) fmul %st(3),%st(0) // t = t/z * z fxch %st(1) fistpl snext fistpl tnext movl snext,%eax movl tnext,%edx subl $8,%ecx // count off this segments' pixels movl C(sadjust),%ebp pushl %ecx // remember count of remaining pixels movl C(tadjust),%ecx addl %eax,%ebp addl %edx,%ecx movl C(bbextents),%eax movl C(bbextentt),%edx cmpl $2048,%ebp jl LClampLow2 cmpl %eax,%ebp ja LClampHigh2 LClampReentry2: cmpl $2048,%ecx jl LClampLow3 cmpl %edx,%ecx ja LClampHigh3 LClampReentry3: movl %ebp,snext movl %ecx,tnext subl s,%ebp subl t,%ecx // // set up advancetable // movl %ecx,%eax movl %ebp,%edx sarl $19,%edx // sstep >>= 16; movl C(cachewidth),%ebx sarl $19,%eax // tstep >>= 16; jz LIsZero imull %ebx,%eax // (tstep >> 16) * cachewidth; LIsZero: addl %edx,%eax // add in sstep // (tstep >> 16) * cachewidth + (sstep >> 16); movl tfracf,%edx movl %eax,advancetable+4 // advance base in t addl %ebx,%eax // ((tstep >> 16) + 1) * cachewidth + // (sstep >> 16); shll $13,%ebp // left-justify sstep fractional part movl %ebp,sstep movl sfracf,%ebx shll $13,%ecx // left-justify tstep fractional part movl %eax,advancetable // advance extra in t movl %ecx,tstep movl pz,%ecx movl izi,%ebp cmpw (%ecx),%bp jl Lp1 movb (%esi),%al // get first source texel cmpb $(TRANSPARENT_COLOR),%al jz Lp1 movw %bp,(%ecx) movb %al,(%edi) // store first dest pixel Lp1: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx // advance tfrac fractional part by tstep frac sbbl %eax,%eax // turn tstep carry into -1 (0 if none) addl sstep,%ebx // advance sfrac fractional part by sstep frac adcl advancetable+4(,%eax,4),%esi // point to next source texel cmpw 2(%ecx),%bp jl Lp2 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp2 movw %bp,2(%ecx) movb %al,1(%edi) Lp2: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi cmpw 4(%ecx),%bp jl Lp3 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp3 movw %bp,4(%ecx) movb %al,2(%edi) Lp3: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi cmpw 6(%ecx),%bp jl Lp4 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp4 movw %bp,6(%ecx) movb %al,3(%edi) Lp4: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi cmpw 8(%ecx),%bp jl Lp5 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp5 movw %bp,8(%ecx) movb %al,4(%edi) Lp5: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi // // start FDIV for end of next segment in flight, so it can overlap // popl %eax cmpl $8,%eax // more than one segment after this? ja LSetupNotLast2 // yes decl %eax jz LFDIVInFlight2 // if only one pixel, no need to start an FDIV movl %eax,spancountminus1 fildl spancountminus1 flds C(d_zistepu) // _d_zistepu | spancountminus1 fmul %st(1),%st(0) // _d_zistepu*scm1 | scm1 flds C(d_tdivzstepu) // _d_tdivzstepu | _d_zistepu*scm1 | scm1 fmul %st(2),%st(0) // _d_tdivzstepu*scm1 | _d_zistepu*scm1 | scm1 fxch %st(1) // _d_zistepu*scm1 | _d_tdivzstepu*scm1 | scm1 faddp %st(0),%st(3) // _d_tdivzstepu*scm1 | scm1 fxch %st(1) // scm1 | _d_tdivzstepu*scm1 fmuls C(d_sdivzstepu) // _d_sdivzstepu*scm1 | _d_tdivzstepu*scm1 fxch %st(1) // _d_tdivzstepu*scm1 | _d_sdivzstepu*scm1 faddp %st(0),%st(3) // _d_sdivzstepu*scm1 flds fp_64k // 64k | _d_sdivzstepu*scm1 fxch %st(1) // _d_sdivzstepu*scm1 | 64k faddp %st(0),%st(4) // 64k fdiv %st(1),%st(0) // this is what we've gone to all this trouble to // overlap jmp LFDIVInFlight2 .align 4 LSetupNotLast2: fadds zi8stepu fxch %st(2) fadds sdivz8stepu fxch %st(2) flds tdivz8stepu faddp %st(0),%st(2) flds fp_64k fdiv %st(1),%st(0) // z = 1/1/z // this is what we've gone to all this trouble to // overlap LFDIVInFlight2: pushl %eax cmpw 10(%ecx),%bp jl Lp6 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp6 movw %bp,10(%ecx) movb %al,5(%edi) Lp6: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi cmpw 12(%ecx),%bp jl Lp7 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp7 movw %bp,12(%ecx) movb %al,6(%edi) Lp7: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi cmpw 14(%ecx),%bp jl Lp8 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp8 movw %bp,14(%ecx) movb %al,7(%edi) Lp8: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi addl $8,%edi addl $16,%ecx movl %edx,tfracf movl snext,%edx movl %ebx,sfracf movl tnext,%ebx movl %edx,s movl %ebx,t movl %ecx,pz movl %ebp,izi popl %ecx // retrieve count // // determine whether last span or not // cmpl $8,%ecx // are there multiple segments remaining? ja LNotLastSegment // yes // // last segment of scan // LLastSegment: // // advance s/z, t/z, and 1/z, and calculate s & t at end of span and steps to // get there. The number of pixels left is variable, and we want to land on the // last pixel, not step one past it, so we can't run into arithmetic problems // testl %ecx,%ecx jz LNoSteps // just draw the last pixel and we're done // pick up after the FDIV that was left in flight previously fld %st(0) // duplicate it fmul %st(4),%st(0) // s = s/z * z fxch %st(1) fmul %st(3),%st(0) // t = t/z * z fxch %st(1) fistpl snext fistpl tnext movl C(tadjust),%ebx movl C(sadjust),%eax addl snext,%eax addl tnext,%ebx movl C(bbextents),%ebp movl C(bbextentt),%edx cmpl $2048,%eax jl LClampLow4 cmpl %ebp,%eax ja LClampHigh4 LClampReentry4: movl %eax,snext cmpl $2048,%ebx jl LClampLow5 cmpl %edx,%ebx ja LClampHigh5 LClampReentry5: cmpl $1,%ecx // don't bother je LOnlyOneStep // if two pixels in segment, there's only one step, // of the segment length subl s,%eax subl t,%ebx addl %eax,%eax // convert to 15.17 format so multiply by 1.31 addl %ebx,%ebx // reciprocal yields 16.48 imull reciprocal_table-8(,%ecx,4) // sstep = (snext - s) / (spancount-1) movl %edx,%ebp movl %ebx,%eax imull reciprocal_table-8(,%ecx,4) // tstep = (tnext - t) / (spancount-1) LSetEntryvec: // // set up advancetable // movl spr8entryvec_table(,%ecx,4),%ebx movl %edx,%eax pushl %ebx // entry point into code for RET later movl %ebp,%ecx sarl $16,%ecx // sstep >>= 16; movl C(cachewidth),%ebx sarl $16,%edx // tstep >>= 16; jz LIsZeroLast imull %ebx,%edx // (tstep >> 16) * cachewidth; LIsZeroLast: addl %ecx,%edx // add in sstep // (tstep >> 16) * cachewidth + (sstep >> 16); movl tfracf,%ecx movl %edx,advancetable+4 // advance base in t addl %ebx,%edx // ((tstep >> 16) + 1) * cachewidth + // (sstep >> 16); shll $16,%ebp // left-justify sstep fractional part movl sfracf,%ebx shll $16,%eax // left-justify tstep fractional part movl %edx,advancetable // advance extra in t movl %eax,tstep movl %ebp,sstep movl %ecx,%edx movl pz,%ecx movl izi,%ebp ret // jump to the number-of-pixels handler //---------------------------------------- LNoSteps: movl pz,%ecx subl $7,%edi // adjust for hardwired offset subl $14,%ecx jmp LEndSpan LOnlyOneStep: subl s,%eax subl t,%ebx movl %eax,%ebp movl %ebx,%edx jmp LSetEntryvec //---------------------------------------- .globl Spr8Entry2_8 Spr8Entry2_8: subl $6,%edi // adjust for hardwired offsets subl $12,%ecx movb (%esi),%al jmp LLEntry2_8 //---------------------------------------- .globl Spr8Entry3_8 Spr8Entry3_8: subl $5,%edi // adjust for hardwired offsets subl $10,%ecx jmp LLEntry3_8 //---------------------------------------- .globl Spr8Entry4_8 Spr8Entry4_8: subl $4,%edi // adjust for hardwired offsets subl $8,%ecx jmp LLEntry4_8 //---------------------------------------- .globl Spr8Entry5_8 Spr8Entry5_8: subl $3,%edi // adjust for hardwired offsets subl $6,%ecx jmp LLEntry5_8 //---------------------------------------- .globl Spr8Entry6_8 Spr8Entry6_8: subl $2,%edi // adjust for hardwired offsets subl $4,%ecx jmp LLEntry6_8 //---------------------------------------- .globl Spr8Entry7_8 Spr8Entry7_8: decl %edi // adjust for hardwired offsets subl $2,%ecx jmp LLEntry7_8 //---------------------------------------- .globl Spr8Entry8_8 Spr8Entry8_8: cmpw (%ecx),%bp jl Lp9 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp9 movw %bp,(%ecx) movb %al,(%edi) Lp9: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi LLEntry7_8: cmpw 2(%ecx),%bp jl Lp10 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp10 movw %bp,2(%ecx) movb %al,1(%edi) Lp10: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi LLEntry6_8: cmpw 4(%ecx),%bp jl Lp11 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp11 movw %bp,4(%ecx) movb %al,2(%edi) Lp11: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi LLEntry5_8: cmpw 6(%ecx),%bp jl Lp12 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp12 movw %bp,6(%ecx) movb %al,3(%edi) Lp12: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi LLEntry4_8: cmpw 8(%ecx),%bp jl Lp13 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp13 movw %bp,8(%ecx) movb %al,4(%edi) Lp13: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi LLEntry3_8: cmpw 10(%ecx),%bp jl Lp14 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp14 movw %bp,10(%ecx) movb %al,5(%edi) Lp14: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi LLEntry2_8: cmpw 12(%ecx),%bp jl Lp15 movb (%esi),%al cmpb $(TRANSPARENT_COLOR),%al jz Lp15 movw %bp,12(%ecx) movb %al,6(%edi) Lp15: addl izistep,%ebp adcl $0,%ebp addl tstep,%edx sbbl %eax,%eax addl sstep,%ebx adcl advancetable+4(,%eax,4),%esi LEndSpan: cmpw 14(%ecx),%bp jl Lp16 movb (%esi),%al // load first texel in segment cmpb $(TRANSPARENT_COLOR),%al jz Lp16 movw %bp,14(%ecx) movb %al,7(%edi) Lp16: // // clear s/z, t/z, 1/z from FP stack // fstp %st(0) fstp %st(0) fstp %st(0) popl %ebx // restore spans pointer LNextSpan: addl $(sspan_t_size),%ebx // point to next span movl sspan_t_count(%ebx),%ecx cmpl $0,%ecx // any more spans? jg LSpanLoop // yes jz LNextSpan // yes, but this one's empty popl %ebx // restore register variables popl %esi popl %edi popl %ebp // restore the caller's stack frame ret #endif // id386