reactos/win32ss/gdi/dib/dib24bppc.c

   1 /*
   2  * PROJECT:         Win32 subsystem
   3  * LICENSE:         See COPYING in the top level directory
   4  * FILE:            subsystems/win32/win32k/dib/dib24bppc.c
   5  * PURPOSE:         C language equivalents of asm optimised 24bpp functions
   6  * PROGRAMMERS:     Jason Filby
   7  *                  Magnus Olsen
   8  */
   9
  10 #include <win32k.h>
  11
  12 #define NDEBUG
  13 #include <debug.h>
  14
  15 VOID
  16 DIB_24BPP_HLine(SURFOBJ *SurfObj, LONG x1, LONG x2, LONG y, ULONG c)
  17 {
  18   PBYTE addr = (PBYTE)SurfObj->pvScan0 + y * SurfObj->lDelta + (x1 << 1) + x1;
  19   ULONG Count = x2 - x1;
  20
  21   if (Count < 8)
  22   {
  23     /* For small fills, don't bother doing anything fancy */
  24     while (Count--)
  25     {
  26       *(PUSHORT)(addr) = c;
  27       addr += 2;
  28       *(addr) = c >> 16;
  29       addr += 1;
  30     }
  31   }
  32   else
  33   {
  34     ULONG Fill[3];
  35     ULONG MultiCount;
  36
  37     /* Align to 4-byte address */
  38     while (0 != ((ULONG_PTR) addr & 0x3))
  39     {
  40       *(PUSHORT)(addr) = c;
  41       addr += 2;
  42       *(addr) = c >> 16;
  43       addr += 1;
  44       Count--;
  45     }
  46     /* If the color we need to fill with is 0ABC, then the final mem pattern
  47     * (note little-endianness) would be:
  48     *
  49     * |C.B.A|C.B.A|C.B.A|C.B.A|   <- pixel borders
  50     * |C.B.A.C|B.A.C.B|A.C.B.A|   <- ULONG borders
  51     *
  52     * So, taking endianness into account again, we need to fill with these
  53     * ULONGs: CABC BCAB ABCA */
  54
  55     c = c & 0xffffff;                /* 0ABC */
  56     Fill[0] = c | (c << 24);         /* CABC */
  57     Fill[1] = (c >> 8) | (c << 16);  /* BCAB */
  58     Fill[2] = (c << 8) | (c >> 16);  /* ABCA */
  59     MultiCount = Count / 4;
  60     do
  61     {
  62       *(PULONG)addr = Fill[0];
  63       addr += 4;
  64       *(PULONG)addr = Fill[1];
  65       addr += 4;
  66       *(PULONG)addr = Fill[2];
  67       addr += 4;
  68     }
  69     while (0 != --MultiCount);
  70
  71     Count = Count & 0x03;
  72     while (0 != Count--)
  73     {
  74       *(PUSHORT)(addr) = c;
  75       addr += 2;
  76       *(addr) = c >> 16;
  77       addr += 1;
  78     }
  79   }
  80 }