vid_copy.s

The source code of Doom legacy for windows

// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id: vid_copy.s,v 1.2 2000/02/27 00:42:11 hurdler Exp $
//
// Copyright (C) 1998-2000 by DooM Legacy Team.
//
// 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.
//
//
// $Log: vid_copy.s,v $
// Revision 1.2  2000/02/27 00:42:11  hurdler
// fix CR+LF problem
//
// Revision 1.1.1.1  2000/02/22 20:32:32  hurdler
// Initial import into CVS (v1.29 pr3)
//
//
// DESCRIPTION:
//      code for updating the linear frame buffer screen.
//
//-----------------------------------------------------------------------------


#include "asm_defs.inc"           // structures, must match the C structures!

// DJGPPv2 is as fast as this one, but then someone may compile with a less
// good version of DJGPP than mine, so this little asm will do the trick!

#define srcptr          4+16
#define destptr         8+16
#define width           12+16
#define height          16+16
#define srcrowbytes     20+16
#define destrowbytes    24+16

// VID_BlitLinearScreen( src, dest, width, height, srcwidth, destwidth );
//         width is given as BYTES

.globl C(VID_BlitLinearScreen)
C(VID_BlitLinearScreen):
    pushl   %ebp                // preserve caller's stack frame
    pushl   %edi
    pushl   %esi                // preserve register variables
    pushl   %ebx

    cld
    movl    srcptr(%esp),%esi
    movl    destptr(%esp),%edi
    movl    width(%esp),%ebx
    movl    srcrowbytes(%esp),%eax
    subl    %ebx,%eax
    movl    destrowbytes(%esp),%edx
    subl    %ebx,%edx
    shrl    $2,%ebx
    movl    height(%esp),%ebp
LLRowLoop:
    movl    %ebx,%ecx
    rep/movsl   (%esi),(%edi)
    addl    %eax,%esi
    addl    %edx,%edi
    decl    %ebp
    jnz     LLRowLoop

    popl    %ebx                // restore register variables
    popl    %esi
    popl    %edi
    popl    %ebp                // restore the caller's stack frame

    ret