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      1 /*
      2 Copyright (C) 1996-1997 Id Software, Inc.
      3 
      4 This program is free software; you can redistribute it and/or
      5 modify it under the terms of the GNU General Public License
      6 as published by the Free Software Foundation; either version 2
      7 of the License, or (at your option) any later version.
      8 
      9 This program is distributed in the hope that it will be useful,
     10 but WITHOUT ANY WARRANTY; without even the implied warranty of
     11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
     12 
     13 See the GNU General Public License for more details.
     14 
     15 You should have received a copy of the GNU General Public License
     16 along with this program; if not, write to the Free Software
     17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
     18 
     19 */
     20 //
     21 // d_scana.s
     22 // x86 assembly-language turbulent texture mapping code
     23 //
     24 
     25 #include "asm_i386.h"
     26 #include "quakeasm.h"
     27 #include "asm_draw.h"
     28 #include "d_ifacea.h"
     29 
     30 #if id386
     31 
     32 	.data
     33 
     34 	.text
     35 
     36 //----------------------------------------------------------------------
     37 // turbulent texture mapping code
     38 //----------------------------------------------------------------------
     39 
     40 	.align 4
     41 .globl C(D_DrawTurbulent8Span)
     42 C(D_DrawTurbulent8Span):
     43 	pushl	%ebp				// preserve caller's stack frame pointer
     44 	pushl	%esi				// preserve register variables
     45 	pushl	%edi
     46 	pushl	%ebx
     47 
     48 	movl	C(r_turb_s),%esi
     49 	movl	C(r_turb_t),%ecx
     50 	movl	C(r_turb_pdest),%edi
     51 	movl	C(r_turb_spancount),%ebx
     52 
     53 Llp:
     54 	movl	%ecx,%eax
     55 	movl	%esi,%edx
     56 	sarl	$16,%eax
     57 	movl	C(r_turb_turb),%ebp
     58 	sarl	$16,%edx
     59 	andl	$(CYCLE-1),%eax
     60 	andl	$(CYCLE-1),%edx
     61 	movl	(%ebp,%eax,4),%eax
     62 	movl	(%ebp,%edx,4),%edx
     63 	addl	%esi,%eax
     64 	sarl	$16,%eax
     65 	addl	%ecx,%edx
     66 	sarl	$16,%edx
     67 	andl	$(TURB_TEX_SIZE-1),%eax
     68 	andl	$(TURB_TEX_SIZE-1),%edx
     69 	shll	$6,%edx
     70 	movl	C(r_turb_pbase),%ebp
     71 	addl	%eax,%edx
     72 	incl	%edi
     73 	addl	C(r_turb_sstep),%esi
     74 	addl	C(r_turb_tstep),%ecx
     75 	movb	(%ebp,%edx,1),%dl
     76 	decl	%ebx
     77 	movb	%dl,-1(%edi)
     78 	jnz		Llp
     79 
     80 	movl	%edi,C(r_turb_pdest)
     81 
     82 	popl	%ebx				// restore register variables
     83 	popl	%edi
     84 	popl	%esi
     85 	popl	%ebp				// restore caller's stack frame pointer
     86 	ret
     87 
     88 #endif	// id386
     89 
     90