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GPU: 

- In the SSE2 version of ConvertColor555To8888Opaque(), change the algorithm to use computation instead of memory lookups. Although memory lookups are faster on newer CPUs, computation is much faster on older CPUs, which have smaller caches and longer memory latencies. I believe this is the correct decision, since older CPUs are the ones that need as much performance as they can get.
This commit is contained in:
rogerman 2016-06-18 22:20:07 +00:00
parent 0110fe22d6
commit d1a8663acb
1 changed files with 1 additions and 34 deletions
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35
desmume/src/GPU.h
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@ -1758,12 +1758,8 @@ FORCEINLINE u16 ConvertColor6665To5551(FragmentColor srcColor)
template <bool SWAP_RB>
FORCEINLINE void ConvertColor555To8888Opaque(const __m128i src, __m128i &dstLo, __m128i &dstHi)
{
#if 0
// I'm shelving this code until the time when I figure out how to do this conversion faster in SSE2
// without using any memory lookups. This code does work, albeit slowly. -- rogerman, 2016-06-17
// Conversion algorithm:
// RGB 5-bit to 8-bit formula: dstRGB8 = (srcRGB8 << 3) | ((srcRGB8 >> 2) & 0x07)
// RGB 5-bit to 8-bit formula: dstRGB8 = (srcRGB5 << 3) | ((srcRGB5 >> 2) & 0x07)
if (SWAP_RB)
{
dstLo = _mm_or_si128(_mm_and_si128(_mm_slli_epi32(src, 19), _mm_set1_epi32(0x00F80000)), _mm_and_si128(_mm_slli_epi32(src, 14), _mm_set1_epi32(0x00070000)));
@ -1792,35 +1788,6 @@ FORCEINLINE void ConvertColor555To8888Opaque(const __m128i src, __m128i &dstLo,
__m128i tmpDstLo = dstLo;
dstLo = _mm_or_si128( _mm_and_si128(_mm_shuffle_epi32(tmpDstLo, 0xD8), _mm_set_epi32(0x00000000, 0xFFFFFFFF, 0x00000000, 0xFFFFFFFF)), _mm_and_si128(_mm_shuffle_epi32(dstHi, 0x72), _mm_set_epi32(0xFFFFFFFF, 0x00000000, 0xFFFFFFFF, 0x00000000)) );
dstHi = _mm_or_si128( _mm_and_si128(_mm_shuffle_epi32(tmpDstLo, 0x72), _mm_set_epi32(0x00000000, 0xFFFFFFFF, 0x00000000, 0xFFFFFFFF)), _mm_and_si128(_mm_shuffle_epi32(dstHi, 0xD8), _mm_set_epi32(0xFFFFFFFF, 0x00000000, 0xFFFFFFFF, 0x00000000)) );
#else
// This code does the same thing as the above, but with memory lookups. It's faster, but kinda
// defeats the purpose of using SSE2 due to the memory lookups. -- rogerman, 2016-06-17
__m128i srcMasked = _mm_and_si128(src, _mm_set1_epi16(0x7FFF));
if (SWAP_RB)
{
dstHi = _mm_set_epi32(COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 7)),
COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 6)),
COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 5)),
COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 4)));
dstLo = _mm_set_epi32(COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 3)),
COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 2)),
COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 1)),
COLOR555TO8888_OPAQUE_SWAP_RB(_mm_extract_epi16(srcMasked, 0)));
}
else
{
dstHi = _mm_set_epi32(COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 7)),
COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 6)),
COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 5)),
COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 4)));
dstLo = _mm_set_epi32(COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 3)),
COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 2)),
COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 1)),
COLOR555TO8888_OPAQUE(_mm_extract_epi16(srcMasked, 0)));
}
#endif
}
template <bool SWAP_RB>