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Slight optimization of ycc_to_rgb

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This commit is contained in:
Couriersud 2008-08-24 23:41:46 +00:00
parent 4d444b5b4a
commit 5e6fdaec16
1 changed files with 10 additions and 13 deletions
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23
src/emu/rendersw.c
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@ -120,6 +120,8 @@ INLINE float round_nearest(float f)
contains Y in the LSB, Cb << 8, and Cr << 16
-------------------------------------------------*/
#define CLSH(x) (((INT32) x < 0) ? 0 : x >> 8)
INLINE UINT32 ycc_to_rgb(UINT32 ycc)
{
/* original equations:
@ -147,23 +149,18 @@ INLINE UINT32 ycc_to_rgb(UINT32 ycc)
UINT8 y = ycc;
UINT8 cb = ycc >> 8;
UINT8 cr = ycc >> 16;
int r, g, b, common;
UINT32 r, g, b, common;
common = 298 * y - 298 * 16;
r = (common + 409 * cr - 409 * 128 + 128) >> 8;
g = (common - 100 * cb + 100 * 128 - 208 * cr + 208 * 128 + 128) >> 8;
b = (common + 516 * cb - 516 * 128 + 128) >> 8;
common = 298 * y - 56992;
r = (common + 409 * cr);
g = (common - 100 * cb - 208 * cr + 91776);
b = (common + 516 * cb - 13696);
if (r < 0) r = 0;
else if (r > 255) r = 255;
if (g < 0) g = 0;
else if (g > 255) g = 255;
if (b < 0) b = 0;
else if (b > 255) b = 255;
return MAKE_RGB(r, g, b);
/* MAKE_RGB does upper clamping */
return MAKE_RGB(CLSH(r), CLSH(g), CLSH(b));
}
#undef CLSH
/*-------------------------------------------------
get_texel_palette16_nearest - return the