Games/Quake/d_scana.s

   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