SSSE3 implementation of IA8 texture decode. Roughly 50% faster than SSE2 version on my computer (SSSE3: 77%, SSE2: 57% vs reference C on Core2 Duo). About half as many cycles.

git-svn-id: https://dolphin-emu.googlecode.com/svn/trunk@6770 8ced0084-cf51-0410-be5f-012b33b47a6e
This commit is contained in:
xsacha 2011-01-07 14:55:05 +00:00
parent a6acc99a89
commit dcbfd4ea4c

View File

@ -1230,55 +1230,74 @@ PC_TexFormat TexDecoder_Decode_RGBA(u32 * dst, const u8 * src, int width, int he
break;
case GX_TF_IA8:
{
// JSD optimized with SSE2 intrinsics.
// Produces an ~80% speed improvement over reference C implementation.
const __m128i kMask_xf0 = _mm_set_epi32(0x00000000L, 0x00000000L, 0xff00ff00L, 0xff00ff00L);
const __m128i kMask_x0f = _mm_set_epi32(0x00000000L, 0x00000000L, 0x00ff00ffL, 0x00ff00ffL);
const __m128i kMask_xf000 = _mm_set_epi32(0xff000000L, 0xff000000L, 0xff000000L, 0xff000000L);
const __m128i kMask_x0fff = _mm_set_epi32(0x00ffffffL, 0x00ffffffL, 0x00ffffffL, 0x00ffffffL);
#if _M_SSE >= 0x301
// SSSE3 implementation is approximately 50% faster than SSE2 version.
if (cpu_info.bSSSE3)
{
for (int y = 0; y < height; y += 4)
for (int x = 0; x < width; x += 4)
for (int iy = 0; iy < 4; iy++, src += 8)
{
const __m128i mask = _mm_set_epi8(6, 7, 7, 7, 4, 5, 5, 5, 2, 3, 3, 3, 0, 1, 1, 1);
// Load 4x 16-bit IA8 samples from `src` into an __m128i with upper 64 bits zeroed: (0000 0000 hgfe dcba)
const __m128i r0 = _mm_loadl_epi64((const __m128i *)src);
// Shuffle to (ghhh efff cddd abbb)
const __m128i r1 = _mm_shuffle_epi8(r0, mask);
_mm_storeu_si128( (__m128i*)(dst + (y + iy) * width + x), r1 );
}
} else
#endif
{
// JSD optimized with SSE2 intrinsics.
// Produces an ~80% speed improvement over reference C implementation.
const __m128i kMask_xf0 = _mm_set_epi32(0x00000000L, 0x00000000L, 0xff00ff00L, 0xff00ff00L);
const __m128i kMask_x0f = _mm_set_epi32(0x00000000L, 0x00000000L, 0x00ff00ffL, 0x00ff00ffL);
const __m128i kMask_xf000 = _mm_set_epi32(0xff000000L, 0xff000000L, 0xff000000L, 0xff000000L);
const __m128i kMask_x0fff = _mm_set_epi32(0x00ffffffL, 0x00ffffffL, 0x00ffffffL, 0x00ffffffL);
for (int y = 0; y < height; y += 4)
for (int x = 0; x < width; x += 4)
for (int iy = 0; iy < 4; iy++, src += 8)
{
// Expands a 16-bit "IA" to a 32-bit "AIII". Each char is an 8-bit value.
for (int y = 0; y < height; y += 4)
for (int x = 0; x < width; x += 4)
for (int iy = 0; iy < 4; iy++, src += 8)
{
// Expands a 16-bit "IA" to a 32-bit "AIII". Each char is an 8-bit value.
// Load 4x 16-bit IA8 samples from `src` into an __m128i with upper 64 bits zeroed: (0000 0000 hgfe dcba)
const __m128i r0 = _mm_loadl_epi64((const __m128i *)src);
// Load 4x 16-bit IA8 samples from `src` into an __m128i with upper 64 bits zeroed: (0000 0000 hgfe dcba)
const __m128i r0 = _mm_loadl_epi64((const __m128i *)src);
// Logical shift all 16-bit words right by 8 bits (0000 0000 hgfe dcba) to (0000 0000 0h0f 0d0b)
// This gets us only the I components.
const __m128i i0 = _mm_srli_epi16(r0, 8);
// Logical shift all 16-bit words right by 8 bits (0000 0000 hgfe dcba) to (0000 0000 0h0f 0d0b)
// This gets us only the I components.
const __m128i i0 = _mm_srli_epi16(r0, 8);
// Now join up the I components from their original positions but mask out the A components.
// (0000 0000 hgfe dcba) & kMask_xFF00 -> (0000 0000 h0f0 d0b0)
// (0000 0000 h0f0 d0b0) | (0000 0000 0h0f 0d0b) -> (0000 0000 hhff ddbb)
const __m128i i1 = _mm_or_si128(_mm_and_si128(r0, kMask_xf0), i0);
// Now join up the I components from their original positions but mask out the A components.
// (0000 0000 hgfe dcba) & kMask_xFF00 -> (0000 0000 h0f0 d0b0)
// (0000 0000 h0f0 d0b0) | (0000 0000 0h0f 0d0b) -> (0000 0000 hhff ddbb)
const __m128i i1 = _mm_or_si128(_mm_and_si128(r0, kMask_xf0), i0);
// Shuffle low 64-bits with itself to expand from (0000 0000 hhff ddbb) to (hhhh ffff dddd bbbb)
const __m128i i2 = _mm_unpacklo_epi8(i1, i1);
// (hhhh ffff dddd bbbb) & kMask_x0fff -> (0hhh 0fff 0ddd 0bbb)
const __m128i i3 = _mm_and_si128(i2, kMask_x0fff);
// Shuffle low 64-bits with itself to expand from (0000 0000 hhff ddbb) to (hhhh ffff dddd bbbb)
const __m128i i2 = _mm_unpacklo_epi8(i1, i1);
// (hhhh ffff dddd bbbb) & kMask_x0fff -> (0hhh 0fff 0ddd 0bbb)
const __m128i i3 = _mm_and_si128(i2, kMask_x0fff);
// Now that we have the I components in 32-bit word form, time work out the A components into
// their final positions.
// Now that we have the I components in 32-bit word form, time work out the A components into
// their final positions.
// (0000 0000 hgfe dcba) & kMask_x00FF -> (0000 0000 0g0e 0c0a)
const __m128i a0 = _mm_and_si128(r0, kMask_x0f);
// (0000 0000 0g0e 0c0a) -> (00gg 00ee 00cc 00aa)
const __m128i a1 = _mm_unpacklo_epi8(a0, a0);
// (00gg 00ee 00cc 00aa) << 16 -> (gg00 ee00 cc00 aa00)
const __m128i a2 = _mm_slli_epi32(a1, 16);
// (gg00 ee00 cc00 aa00) & kMask_xf000 -> (g000 e000 c000 a000)
const __m128i a3 = _mm_and_si128(a2, kMask_xf000);
// (0000 0000 hgfe dcba) & kMask_x00FF -> (0000 0000 0g0e 0c0a)
const __m128i a0 = _mm_and_si128(r0, kMask_x0f);
// (0000 0000 0g0e 0c0a) -> (00gg 00ee 00cc 00aa)
const __m128i a1 = _mm_unpacklo_epi8(a0, a0);
// (00gg 00ee 00cc 00aa) << 16 -> (gg00 ee00 cc00 aa00)
const __m128i a2 = _mm_slli_epi32(a1, 16);
// (gg00 ee00 cc00 aa00) & kMask_xf000 -> (g000 e000 c000 a000)
const __m128i a3 = _mm_and_si128(a2, kMask_xf000);
// Simply OR up i3 and a3 now and that's our result:
// (0hhh 0fff 0ddd 0bbb) | (g000 e000 c000 a000) -> (ghhh efff cddd abbb)
const __m128i r1 = _mm_or_si128(i3, a3);
// Simply OR up i3 and a3 now and that's our result:
// (0hhh 0fff 0ddd 0bbb) | (g000 e000 c000 a000) -> (ghhh efff cddd abbb)
const __m128i r1 = _mm_or_si128(i3, a3);
// write out the 128-bit result:
_mm_storeu_si128( (__m128i*)(dst + (y + iy) * width + x), r1 );
}
// write out the 128-bit result:
_mm_storeu_si128( (__m128i*)(dst + (y + iy) * width + x), r1 );
}
}
#if 0
// Reference C implementation:
for (int y = 0; y < height; y += 4)