From f97b920b3151458938f6686d14c23cb479ad46b6 Mon Sep 17 00:00:00 2001 From: Brick <6098371+0x1F9F1@users.noreply.github.com> Date: Sat, 12 Aug 2023 18:53:41 +0100 Subject: [PATCH] Optimized SDL_Convert_*_to_*_SSE2 Some of the SDL_Convert_F32_to_*_SSE2 do not explicitly clamp the input, but instead rely on saturating casts. Inputs very far outside the valid [-1.0, 1.0] range may produce an incorrect result, but I believe that is an acceptable trade-off. --- src/audio/SDL_audiotypecvt.c | 581 +++++++++++++++-------------------- 1 file changed, 246 insertions(+), 335 deletions(-) diff --git a/src/audio/SDL_audiotypecvt.c b/src/audio/SDL_audiotypecvt.c index aeb556cd2..74377a200 100644 --- a/src/audio/SDL_audiotypecvt.c +++ b/src/audio/SDL_audiotypecvt.c @@ -89,427 +89,338 @@ AUDIOCVT_FROMFLOAT_SCALAR(S32, Sint32, -2147483648LL, 2147483647, ((Sint32)(samp #ifdef SDL_SSE2_INTRINSICS static void SDL_TARGETING("sse2") SDL_Convert_S8_to_F32_SSE2(float *dst, const Sint8 *src, int num_samples) { - int i; + int i = num_samples; + + /* 1) Flip the sign bit to convert from S8 to U8 format + * 2) Construct a float in the range [65536.0, 65538.0) + * 3) Shift the float range to [-1.0, 1.0) + * dst[i] = i2f((src[i] ^ 0x80) | 0x47800000) - 65537.0 */ + const __m128i zero = _mm_setzero_si128(); + const __m128i flipper = _mm_set1_epi8(-0x80); + const __m128i caster = _mm_set1_epi16(0x4780 /* 0x47800000 = f2i(65536.0) */); + const __m128 offset = _mm_set1_ps(-65537.0); LOG_DEBUG_AUDIO_CONVERT("S8", "F32 (using SSE2)"); - src += num_samples - 1; - dst += num_samples - 1; + while (i >= 16) { + i -= 16; - /* Get dst aligned to 16 bytes (since buffer is growing, we don't have to worry about overreading from src) */ - for (i = num_samples; i && (((size_t)(dst - 15)) & 15); --i, --src, --dst) { - *dst = ((float)*src) * DIVBY128; + const __m128i bytes = _mm_xor_si128(_mm_loadu_si128((const __m128i *)&src[i]), flipper); + + const __m128i shorts1 = _mm_unpacklo_epi8(bytes, zero); + const __m128i shorts2 = _mm_unpackhi_epi8(bytes, zero); + + const __m128 floats1 = _mm_add_ps(_mm_castsi128_ps(_mm_unpacklo_epi16(shorts1, caster)), offset); + const __m128 floats2 = _mm_add_ps(_mm_castsi128_ps(_mm_unpackhi_epi16(shorts1, caster)), offset); + const __m128 floats3 = _mm_add_ps(_mm_castsi128_ps(_mm_unpacklo_epi16(shorts2, caster)), offset); + const __m128 floats4 = _mm_add_ps(_mm_castsi128_ps(_mm_unpackhi_epi16(shorts2, caster)), offset); + + _mm_storeu_ps(&dst[i], floats1); + _mm_storeu_ps(&dst[i + 4], floats2); + _mm_storeu_ps(&dst[i + 8], floats3); + _mm_storeu_ps(&dst[i + 12], floats4); } - src -= 15; - dst -= 15; /* adjust to read SSE blocks from the start. */ - SDL_assert(!i || !(((size_t)dst) & 15)); - - /* Make sure src is aligned too. */ - if (!(((size_t)src) & 15)) { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128i *mmsrc = (const __m128i *)src; - const __m128i zero = _mm_setzero_si128(); - const __m128 divby128 = _mm_set1_ps(DIVBY128); - while (i >= 16) { /* 16 * 8-bit */ - const __m128i bytes = _mm_load_si128(mmsrc); /* get 16 sint8 into an XMM register. */ - /* treat as int16, shift left to clear every other sint16, then back right with sign-extend. Now sint16. */ - const __m128i shorts1 = _mm_srai_epi16(_mm_slli_epi16(bytes, 8), 8); - /* right-shift-sign-extend gets us sint16 with the other set of values. */ - const __m128i shorts2 = _mm_srai_epi16(bytes, 8); - /* unpack against zero to make these int32, shift to make them sign-extend, convert to float, multiply. Whew! */ - const __m128 floats1 = _mm_mul_ps(_mm_cvtepi32_ps(_mm_srai_epi32(_mm_slli_epi32(_mm_unpacklo_epi16(shorts1, zero), 16), 16)), divby128); - const __m128 floats2 = _mm_mul_ps(_mm_cvtepi32_ps(_mm_srai_epi32(_mm_slli_epi32(_mm_unpacklo_epi16(shorts2, zero), 16), 16)), divby128); - const __m128 floats3 = _mm_mul_ps(_mm_cvtepi32_ps(_mm_srai_epi32(_mm_slli_epi32(_mm_unpackhi_epi16(shorts1, zero), 16), 16)), divby128); - const __m128 floats4 = _mm_mul_ps(_mm_cvtepi32_ps(_mm_srai_epi32(_mm_slli_epi32(_mm_unpackhi_epi16(shorts2, zero), 16), 16)), divby128); - /* Interleave back into correct order, store. */ - _mm_store_ps(dst, _mm_unpacklo_ps(floats1, floats2)); - _mm_store_ps(dst + 4, _mm_unpackhi_ps(floats1, floats2)); - _mm_store_ps(dst + 8, _mm_unpacklo_ps(floats3, floats4)); - _mm_store_ps(dst + 12, _mm_unpackhi_ps(floats3, floats4)); - i -= 16; - mmsrc--; - dst -= 16; - } - - src = (const Sint8 *)mmsrc; - } - - src += 15; - dst += 15; /* adjust for any scalar finishing. */ - - /* Finish off any leftovers with scalar operations. */ while (i) { - *dst = ((float)*src) * DIVBY128; - i--; - src--; - dst--; + --i; + _mm_store_ss(&dst[i], _mm_add_ss(_mm_castsi128_ps(_mm_cvtsi32_si128((Uint8)src[i] ^ 0x47800080u)), offset)); } } static void SDL_TARGETING("sse2") SDL_Convert_U8_to_F32_SSE2(float *dst, const Uint8 *src, int num_samples) { - int i; + int i = num_samples; + + /* 1) Construct a float in the range [65536.0, 65538.0) + * 2) Shift the float range to [-1.0, 1.0) + * dst[i] = i2f(src[i] | 0x47800000) - 65537.0 */ + const __m128i zero = _mm_setzero_si128(); + const __m128i caster = _mm_set1_epi16(0x4780 /* 0x47800000 = f2i(65536.0) */); + const __m128 offset = _mm_set1_ps(-65537.0); LOG_DEBUG_AUDIO_CONVERT("U8", "F32 (using SSE2)"); - src += num_samples - 1; - dst += num_samples - 1; + while (i >= 16) { + i -= 16; - /* Get dst aligned to 16 bytes (since buffer is growing, we don't have to worry about overreading from src) */ - for (i = num_samples; i && (((size_t)(dst - 15)) & 15); --i, --src, --dst) { - *dst = (((float)*src) * DIVBY128) - 1.0f; + const __m128i bytes = _mm_loadu_si128((const __m128i *)&src[i]); + + const __m128i shorts1 = _mm_unpacklo_epi8(bytes, zero); + const __m128i shorts2 = _mm_unpackhi_epi8(bytes, zero); + + const __m128 floats1 = _mm_add_ps(_mm_castsi128_ps(_mm_unpacklo_epi16(shorts1, caster)), offset); + const __m128 floats2 = _mm_add_ps(_mm_castsi128_ps(_mm_unpackhi_epi16(shorts1, caster)), offset); + const __m128 floats3 = _mm_add_ps(_mm_castsi128_ps(_mm_unpacklo_epi16(shorts2, caster)), offset); + const __m128 floats4 = _mm_add_ps(_mm_castsi128_ps(_mm_unpackhi_epi16(shorts2, caster)), offset); + + _mm_storeu_ps(&dst[i], floats1); + _mm_storeu_ps(&dst[i + 4], floats2); + _mm_storeu_ps(&dst[i + 8], floats3); + _mm_storeu_ps(&dst[i + 12], floats4); } - src -= 15; - dst -= 15; /* adjust to read SSE blocks from the start. */ - SDL_assert(!i || !(((size_t)dst) & 15)); - - /* Make sure src is aligned too. */ - if (!(((size_t)src) & 15)) { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128i *mmsrc = (const __m128i *)src; - const __m128i zero = _mm_setzero_si128(); - const __m128 divby128 = _mm_set1_ps(DIVBY128); - const __m128 minus1 = _mm_set1_ps(-1.0f); - while (i >= 16) { /* 16 * 8-bit */ - const __m128i bytes = _mm_load_si128(mmsrc); /* get 16 uint8 into an XMM register. */ - /* treat as int16, shift left to clear every other sint16, then back right with zero-extend. Now uint16. */ - const __m128i shorts1 = _mm_srli_epi16(_mm_slli_epi16(bytes, 8), 8); - /* right-shift-zero-extend gets us uint16 with the other set of values. */ - const __m128i shorts2 = _mm_srli_epi16(bytes, 8); - /* unpack against zero to make these int32, convert to float, multiply, add. Whew! */ - /* Note that AVX2 can do floating point multiply+add in one instruction, fwiw. SSE2 cannot. */ - const __m128 floats1 = _mm_add_ps(_mm_mul_ps(_mm_cvtepi32_ps(_mm_unpacklo_epi16(shorts1, zero)), divby128), minus1); - const __m128 floats2 = _mm_add_ps(_mm_mul_ps(_mm_cvtepi32_ps(_mm_unpacklo_epi16(shorts2, zero)), divby128), minus1); - const __m128 floats3 = _mm_add_ps(_mm_mul_ps(_mm_cvtepi32_ps(_mm_unpackhi_epi16(shorts1, zero)), divby128), minus1); - const __m128 floats4 = _mm_add_ps(_mm_mul_ps(_mm_cvtepi32_ps(_mm_unpackhi_epi16(shorts2, zero)), divby128), minus1); - /* Interleave back into correct order, store. */ - _mm_store_ps(dst, _mm_unpacklo_ps(floats1, floats2)); - _mm_store_ps(dst + 4, _mm_unpackhi_ps(floats1, floats2)); - _mm_store_ps(dst + 8, _mm_unpacklo_ps(floats3, floats4)); - _mm_store_ps(dst + 12, _mm_unpackhi_ps(floats3, floats4)); - i -= 16; - mmsrc--; - dst -= 16; - } - - src = (const Uint8 *)mmsrc; - } - - src += 15; - dst += 15; /* adjust for any scalar finishing. */ - - /* Finish off any leftovers with scalar operations. */ while (i) { - *dst = (((float)*src) * DIVBY128) - 1.0f; - i--; - src--; - dst--; + --i; + _mm_store_ss(&dst[i], _mm_add_ss(_mm_castsi128_ps(_mm_cvtsi32_si128((Uint8)src[i] ^ 0x47800000u)), offset)); } } static void SDL_TARGETING("sse2") SDL_Convert_S16_to_F32_SSE2(float *dst, const Sint16 *src, int num_samples) { - int i; + int i = num_samples; + + /* 1) Flip the sign bit to convert from S16 to U16 format + * 2) Construct a float in the range [256.0, 258.0) + * 3) Shift the float range to [-1.0, 1.0) + * dst[i] = i2f((src[i] ^ 0x8000) | 0x43800000) - 257.0 */ + const __m128i flipper = _mm_set1_epi16(-0x8000); + const __m128i caster = _mm_set1_epi16(0x4380 /* 0x43800000 = f2i(256.0) */); + const __m128 offset = _mm_set1_ps(-257.0f); LOG_DEBUG_AUDIO_CONVERT("S16", "F32 (using SSE2)"); - src += num_samples - 1; - dst += num_samples - 1; + while (i >= 16) { + i -= 16; - /* Get dst aligned to 16 bytes (since buffer is growing, we don't have to worry about overreading from src) */ - for (i = num_samples; i && (((size_t)(dst - 7)) & 15); --i, --src, --dst) { - *dst = ((float)*src) * DIVBY32768; + const __m128i shorts1 = _mm_xor_si128(_mm_loadu_si128((const __m128i *)&src[i]), flipper); + const __m128i shorts2 = _mm_xor_si128(_mm_loadu_si128((const __m128i *)&src[i + 8]), flipper); + + const __m128 floats1 = _mm_add_ps(_mm_castsi128_ps(_mm_unpacklo_epi16(shorts1, caster)), offset); + const __m128 floats2 = _mm_add_ps(_mm_castsi128_ps(_mm_unpackhi_epi16(shorts1, caster)), offset); + const __m128 floats3 = _mm_add_ps(_mm_castsi128_ps(_mm_unpacklo_epi16(shorts2, caster)), offset); + const __m128 floats4 = _mm_add_ps(_mm_castsi128_ps(_mm_unpackhi_epi16(shorts2, caster)), offset); + + _mm_storeu_ps(&dst[i], floats1); + _mm_storeu_ps(&dst[i + 4], floats2); + _mm_storeu_ps(&dst[i + 8], floats3); + _mm_storeu_ps(&dst[i + 12], floats4); } - src -= 7; - dst -= 7; /* adjust to read SSE blocks from the start. */ - SDL_assert(!i || !(((size_t)dst) & 15)); - - /* Make sure src is aligned too. */ - if (!(((size_t)src) & 15)) { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128 divby32768 = _mm_set1_ps(DIVBY32768); - while (i >= 8) { /* 8 * 16-bit */ - const __m128i ints = _mm_load_si128((__m128i const *)src); /* get 8 sint16 into an XMM register. */ - /* treat as int32, shift left to clear every other sint16, then back right with sign-extend. Now sint32. */ - const __m128i a = _mm_srai_epi32(_mm_slli_epi32(ints, 16), 16); - /* right-shift-sign-extend gets us sint32 with the other set of values. */ - const __m128i b = _mm_srai_epi32(ints, 16); - /* Interleave these back into the right order, convert to float, multiply, store. */ - _mm_store_ps(dst, _mm_mul_ps(_mm_cvtepi32_ps(_mm_unpacklo_epi32(a, b)), divby32768)); - _mm_store_ps(dst + 4, _mm_mul_ps(_mm_cvtepi32_ps(_mm_unpackhi_epi32(a, b)), divby32768)); - i -= 8; - src -= 8; - dst -= 8; - } - } - - src += 7; - dst += 7; /* adjust for any scalar finishing. */ - - /* Finish off any leftovers with scalar operations. */ while (i) { - *dst = ((float)*src) * DIVBY32768; - i--; - src--; - dst--; + --i; + _mm_store_ss(&dst[i], _mm_add_ss(_mm_castsi128_ps(_mm_cvtsi32_si128((Uint16)src[i] ^ 0x43808000u)), offset)); } } static void SDL_TARGETING("sse2") SDL_Convert_S32_to_F32_SSE2(float *dst, const Sint32 *src, int num_samples) { - int i; + int i = num_samples; + + /* dst[i] = f32(src[i]) / f32(0x80000000) */ + const __m128 scaler = _mm_set1_ps(0x1p-31f); LOG_DEBUG_AUDIO_CONVERT("S32", "F32 (using SSE2)"); - /* Get dst aligned to 16 bytes */ - for (i = num_samples; i && (((size_t)dst) & 15); --i, ++src, ++dst) { - *dst = ((float)(*src >> 8)) * DIVBY8388607; + while (i >= 16) { + i -= 16; + + const __m128i ints1 = _mm_loadu_si128((const __m128i *)&src[i]); + const __m128i ints2 = _mm_loadu_si128((const __m128i *)&src[i + 4]); + const __m128i ints3 = _mm_loadu_si128((const __m128i *)&src[i + 8]); + const __m128i ints4 = _mm_loadu_si128((const __m128i *)&src[i + 12]); + + const __m128 floats1 = _mm_mul_ps(_mm_cvtepi32_ps(ints1), scaler); + const __m128 floats2 = _mm_mul_ps(_mm_cvtepi32_ps(ints2), scaler); + const __m128 floats3 = _mm_mul_ps(_mm_cvtepi32_ps(ints3), scaler); + const __m128 floats4 = _mm_mul_ps(_mm_cvtepi32_ps(ints4), scaler); + + _mm_storeu_ps(&dst[i], floats1); + _mm_storeu_ps(&dst[i + 4], floats2); + _mm_storeu_ps(&dst[i + 8], floats3); + _mm_storeu_ps(&dst[i + 12], floats4); } - SDL_assert(!i || !(((size_t)dst) & 15)); - - /* Make sure src is aligned too. */ - if (!(((size_t)src) & 15)) { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128 divby8388607 = _mm_set1_ps(DIVBY8388607); - const __m128i *mmsrc = (const __m128i *)src; - while (i >= 4) { /* 4 * sint32 */ - /* shift out lowest bits so int fits in a float32. Small precision loss, but much faster. */ - _mm_store_ps(dst, _mm_mul_ps(_mm_cvtepi32_ps(_mm_srai_epi32(_mm_load_si128(mmsrc), 8)), divby8388607)); - i -= 4; - mmsrc++; - dst += 4; - } - src = (const Sint32 *)mmsrc; - } - - /* Finish off any leftovers with scalar operations. */ while (i) { - *dst = ((float)(*src >> 8)) * DIVBY8388607; - i--; - src++; - dst++; + --i; + _mm_store_ss(&dst[i], _mm_mul_ss(_mm_cvt_si2ss(_mm_setzero_ps(), src[i]), scaler)); } } static void SDL_TARGETING("sse2") SDL_Convert_F32_to_S8_SSE2(Sint8 *dst, const float *src, int num_samples) { - int i; + int i = num_samples; + + /* 1) Shift the float range from [-1.0, 1.0] to [98303.0, 98305.0] + * 2) Extract the lowest 16 bits and clamp to [-128, 127] + * Overflow is correctly handled for inputs between roughly [-255.0, 255.0] + * dst[i] = clamp(i16(f2i(src[i] + 98304.0) & 0xFFFF), -128, 127) */ + const __m128 offset = _mm_set1_ps(98304.0f); + const __m128i mask = _mm_set1_epi16(0xFF); LOG_DEBUG_AUDIO_CONVERT("F32", "S8 (using SSE2)"); - /* Get dst aligned to 16 bytes */ - for (i = num_samples; i && (((size_t)dst) & 15); --i, ++src, ++dst) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 127; - } else if (sample <= -1.0f) { - *dst = -128; - } else { - *dst = (Sint8)(sample * 127.0f); - } + while (i >= 16) { + const __m128 floats1 = _mm_loadu_ps(&src[0]); + const __m128 floats2 = _mm_loadu_ps(&src[4]); + const __m128 floats3 = _mm_loadu_ps(&src[8]); + const __m128 floats4 = _mm_loadu_ps(&src[12]); + + const __m128i ints1 = _mm_castps_si128(_mm_add_ps(floats1, offset)); + const __m128i ints2 = _mm_castps_si128(_mm_add_ps(floats2, offset)); + const __m128i ints3 = _mm_castps_si128(_mm_add_ps(floats3, offset)); + const __m128i ints4 = _mm_castps_si128(_mm_add_ps(floats4, offset)); + + const __m128i shorts1 = _mm_and_si128(_mm_packs_epi16(ints1, ints2), mask); + const __m128i shorts2 = _mm_and_si128(_mm_packs_epi16(ints3, ints4), mask); + + const __m128i bytes = _mm_packus_epi16(shorts1, shorts2); + + _mm_storeu_si128((__m128i*)dst, bytes); + + i -= 16; + src += 16; + dst += 16; } - SDL_assert(!i || !(((size_t)dst) & 15)); - - /* Make sure src is aligned too. */ - if (!(((size_t)src) & 15)) { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128 one = _mm_set1_ps(1.0f); - const __m128 negone = _mm_set1_ps(-1.0f); - const __m128 mulby127 = _mm_set1_ps(127.0f); - __m128i *mmdst = (__m128i *)dst; - while (i >= 16) { /* 16 * float32 */ - const __m128i ints1 = _mm_cvtps_epi32(_mm_mul_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src)), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - const __m128i ints2 = _mm_cvtps_epi32(_mm_mul_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src + 4)), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - const __m128i ints3 = _mm_cvtps_epi32(_mm_mul_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src + 8)), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - const __m128i ints4 = _mm_cvtps_epi32(_mm_mul_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src + 12)), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - _mm_store_si128(mmdst, _mm_packs_epi16(_mm_packs_epi32(ints1, ints2), _mm_packs_epi32(ints3, ints4))); /* pack down, store out. */ - i -= 16; - src += 16; - mmdst++; - } - dst = (Sint8 *)mmdst; - } - - /* Finish off any leftovers with scalar operations. */ while (i) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 127; - } else if (sample <= -1.0f) { - *dst = -128; - } else { - *dst = (Sint8)(sample * 127.0f); - } - i--; - src++; - dst++; + const __m128i ints = _mm_castps_si128(_mm_add_ss(_mm_load_ss(src), offset)); + *dst = (Sint8)(_mm_cvtsi128_si32(_mm_packs_epi16(ints, ints)) & 0xFF); + + --i; + ++src; + ++dst; } } static void SDL_TARGETING("sse2") SDL_Convert_F32_to_U8_SSE2(Uint8 *dst, const float *src, int num_samples) { - int i; + int i = num_samples; + + /* 1) Shift the float range from [-1.0, 1.0] to [98304.0, 98306.0] + * 2) Extract the lowest 16 bits and clamp to [0, 255] + * Overflow is correctly handled for inputs between roughly [-254.0, 254.0] + * dst[i] = clamp(i16(f2i(src[i] + 98305.0) & 0xFFFF), 0, 255) */ + const __m128 offset = _mm_set1_ps(98305.0f); + const __m128i mask = _mm_set1_epi16(0xFF); LOG_DEBUG_AUDIO_CONVERT("F32", "U8 (using SSE2)"); - /* Get dst aligned to 16 bytes */ - for (i = num_samples; i && (((size_t)dst) & 15); --i, ++src, ++dst) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 255; - } else if (sample <= -1.0f) { - *dst = 0; - } else { - *dst = (Uint8)((sample + 1.0f) * 127.0f); - } + while (i >= 16) { + + const __m128 floats1 = _mm_loadu_ps(&src[0]); + const __m128 floats2 = _mm_loadu_ps(&src[4]); + const __m128 floats3 = _mm_loadu_ps(&src[8]); + const __m128 floats4 = _mm_loadu_ps(&src[12]); + + const __m128i ints1 = _mm_castps_si128(_mm_add_ps(floats1, offset)); + const __m128i ints2 = _mm_castps_si128(_mm_add_ps(floats2, offset)); + const __m128i ints3 = _mm_castps_si128(_mm_add_ps(floats3, offset)); + const __m128i ints4 = _mm_castps_si128(_mm_add_ps(floats4, offset)); + + const __m128i shorts1 = _mm_and_si128(_mm_packus_epi16(ints1, ints2), mask); + const __m128i shorts2 = _mm_and_si128(_mm_packus_epi16(ints3, ints4), mask); + + const __m128i bytes = _mm_packus_epi16(shorts1, shorts2); + + _mm_storeu_si128((__m128i*)dst, bytes); + + i -= 16; + src += 16; + dst += 16; } - SDL_assert(!i || !(((size_t)dst) & 15)); - - /* Make sure src is aligned too. */ - if (!(((size_t)src) & 15)) { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128 one = _mm_set1_ps(1.0f); - const __m128 negone = _mm_set1_ps(-1.0f); - const __m128 mulby127 = _mm_set1_ps(127.0f); - __m128i *mmdst = (__m128i *)dst; - while (i >= 16) { /* 16 * float32 */ - const __m128i ints1 = _mm_cvtps_epi32(_mm_mul_ps(_mm_add_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src)), one), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - const __m128i ints2 = _mm_cvtps_epi32(_mm_mul_ps(_mm_add_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src + 4)), one), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - const __m128i ints3 = _mm_cvtps_epi32(_mm_mul_ps(_mm_add_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src + 8)), one), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - const __m128i ints4 = _mm_cvtps_epi32(_mm_mul_ps(_mm_add_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src + 12)), one), one), mulby127)); /* load 4 floats, clamp, convert to sint32 */ - _mm_store_si128(mmdst, _mm_packus_epi16(_mm_packs_epi32(ints1, ints2), _mm_packs_epi32(ints3, ints4))); /* pack down, store out. */ - i -= 16; - src += 16; - mmdst++; - } - dst = (Uint8 *)mmdst; - } - - /* Finish off any leftovers with scalar operations. */ while (i) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 255; - } else if (sample <= -1.0f) { - *dst = 0; - } else { - *dst = (Uint8)((sample + 1.0f) * 127.0f); - } - i--; - src++; - dst++; + const __m128i ints = _mm_castps_si128(_mm_add_ss(_mm_load_ss(src), offset)); + *dst = (Uint8)(_mm_cvtsi128_si32(_mm_packus_epi16(ints, ints)) & 0xFF); + + --i; + ++src; + ++dst; } } static void SDL_TARGETING("sse2") SDL_Convert_F32_to_S16_SSE2(Sint16 *dst, const float *src, int num_samples) { - int i; + int i = num_samples; + + /* 1) Shift the float range from [-1.0, 1.0] to [256.0, 258.0] + * 2) Shift the int range from [0x43800000, 0x43810000] to [-32768,32768] + * 3) Clamp to range [-32768,32767] + * Overflow is correctly handled for inputs between roughly [-257.0, +inf) + * dst[i] = clamp(f2i(src[i] + 257.0) - 0x43808000, -32768, 32767) */ + const __m128 offset = _mm_set1_ps(257.0f); LOG_DEBUG_AUDIO_CONVERT("F32", "S16 (using SSE2)"); - /* Get dst aligned to 16 bytes */ - for (i = num_samples; i && (((size_t)dst) & 15); --i, ++src, ++dst) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 32767; - } else if (sample <= -1.0f) { - *dst = -32768; - } else { - *dst = (Sint16)(sample * 32767.0f); - } + while (i >= 16) { + const __m128 floats1 = _mm_loadu_ps(&src[0]); + const __m128 floats2 = _mm_loadu_ps(&src[4]); + const __m128 floats3 = _mm_loadu_ps(&src[8]); + const __m128 floats4 = _mm_loadu_ps(&src[12]); + + const __m128i ints1 = _mm_sub_epi32(_mm_castps_si128(_mm_add_ps(floats1, offset)), _mm_castps_si128(offset)); + const __m128i ints2 = _mm_sub_epi32(_mm_castps_si128(_mm_add_ps(floats2, offset)), _mm_castps_si128(offset)); + const __m128i ints3 = _mm_sub_epi32(_mm_castps_si128(_mm_add_ps(floats3, offset)), _mm_castps_si128(offset)); + const __m128i ints4 = _mm_sub_epi32(_mm_castps_si128(_mm_add_ps(floats4, offset)), _mm_castps_si128(offset)); + + const __m128i shorts1 = _mm_packs_epi32(ints1, ints2); + const __m128i shorts2 = _mm_packs_epi32(ints3, ints4); + + _mm_storeu_si128((__m128i*)&dst[0], shorts1); + _mm_storeu_si128((__m128i*)&dst[8], shorts2); + + i -= 16; + src += 16; + dst += 16; } - SDL_assert(!i || !(((size_t)dst) & 15)); - - /* Make sure src is aligned too. */ - if (!(((size_t)src) & 15)) { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128 one = _mm_set1_ps(1.0f); - const __m128 negone = _mm_set1_ps(-1.0f); - const __m128 mulby32767 = _mm_set1_ps(32767.0f); - __m128i *mmdst = (__m128i *)dst; - while (i >= 8) { /* 8 * float32 */ - const __m128i ints1 = _mm_cvtps_epi32(_mm_mul_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src)), one), mulby32767)); /* load 4 floats, clamp, convert to sint32 */ - const __m128i ints2 = _mm_cvtps_epi32(_mm_mul_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src + 4)), one), mulby32767)); /* load 4 floats, clamp, convert to sint32 */ - _mm_store_si128(mmdst, _mm_packs_epi32(ints1, ints2)); /* pack to sint16, store out. */ - i -= 8; - src += 8; - mmdst++; - } - dst = (Sint16 *)mmdst; - } - - /* Finish off any leftovers with scalar operations. */ while (i) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 32767; - } else if (sample <= -1.0f) { - *dst = -32768; - } else { - *dst = (Sint16)(sample * 32767.0f); - } - i--; - src++; - dst++; + const __m128i ints = _mm_sub_epi32(_mm_castps_si128(_mm_add_ss(_mm_load_ss(src), offset)), _mm_castps_si128(offset)); + *dst = (Sint16)(_mm_cvtsi128_si32(_mm_packs_epi32(ints, ints)) & 0xFFFF); + + --i; + ++src; + ++dst; } } static void SDL_TARGETING("sse2") SDL_Convert_F32_to_S32_SSE2(Sint32 *dst, const float *src, int num_samples) { - int i; + int i = num_samples; + + /* 1) Scale the float range from [-1.0, 1.0] to [-2147483648.0, 2147483648.0] + * 2) Convert to integer (values too small/large become 0x80000000 = -2147483648) + * 3) Fixup values which were too large (0x80000000 ^ 0xFFFFFFFF = 2147483647) + * dst[i] = i32(src[i] * 2147483648.0) ^ ((src[i] >= 2147483648.0) ? 0xFFFFFFFF : 0x00000000) */ + const __m128 limit = _mm_set1_ps(0x1p31f); LOG_DEBUG_AUDIO_CONVERT("F32", "S32 (using SSE2)"); - /* Get dst aligned to 16 bytes */ - for (i = num_samples; i && (((size_t)dst) & 15); --i, ++src, ++dst) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 2147483647; - } else if (sample <= -1.0f) { - *dst = (Sint32)-2147483648LL; - } else { - *dst = ((Sint32)(sample * 8388607.0f)) << 8; - } + while (i >= 16) { + const __m128 floats1 = _mm_loadu_ps(&src[0]); + const __m128 floats2 = _mm_loadu_ps(&src[4]); + const __m128 floats3 = _mm_loadu_ps(&src[8]); + const __m128 floats4 = _mm_loadu_ps(&src[12]); + + const __m128 values1 = _mm_mul_ps(floats1, limit); + const __m128 values2 = _mm_mul_ps(floats2, limit); + const __m128 values3 = _mm_mul_ps(floats3, limit); + const __m128 values4 = _mm_mul_ps(floats4, limit); + + const __m128i ints1 = _mm_xor_si128(_mm_cvttps_epi32(values1), _mm_castps_si128(_mm_cmpge_ps(values1, limit))); + const __m128i ints2 = _mm_xor_si128(_mm_cvttps_epi32(values2), _mm_castps_si128(_mm_cmpge_ps(values2, limit))); + const __m128i ints3 = _mm_xor_si128(_mm_cvttps_epi32(values3), _mm_castps_si128(_mm_cmpge_ps(values3, limit))); + const __m128i ints4 = _mm_xor_si128(_mm_cvttps_epi32(values4), _mm_castps_si128(_mm_cmpge_ps(values4, limit))); + + _mm_storeu_si128((__m128i*)&dst[0], ints1); + _mm_storeu_si128((__m128i*)&dst[4], ints2); + _mm_storeu_si128((__m128i*)&dst[8], ints3); + _mm_storeu_si128((__m128i*)&dst[12], ints4); + + i -= 16; + src += 16; + dst += 16; } - SDL_assert(!i || !(((size_t)dst) & 15)); - SDL_assert(!i || !(((size_t)src) & 15)); - - { - /* Aligned! Do SSE blocks as long as we have 16 bytes available. */ - const __m128 one = _mm_set1_ps(1.0f); - const __m128 negone = _mm_set1_ps(-1.0f); - const __m128 mulby8388607 = _mm_set1_ps(8388607.0f); - __m128i *mmdst = (__m128i *)dst; - while (i >= 4) { /* 4 * float32 */ - _mm_store_si128(mmdst, _mm_slli_epi32(_mm_cvtps_epi32(_mm_mul_ps(_mm_min_ps(_mm_max_ps(negone, _mm_load_ps(src)), one), mulby8388607)), 8)); /* load 4 floats, clamp, convert to sint32 */ - i -= 4; - src += 4; - mmdst++; - } - dst = (Sint32 *)mmdst; - } - - /* Finish off any leftovers with scalar operations. */ while (i) { - const float sample = *src; - if (sample >= 1.0f) { - *dst = 2147483647; - } else if (sample <= -1.0f) { - *dst = (Sint32)-2147483648LL; - } else { - *dst = ((Sint32)(sample * 8388607.0f)) << 8; - } - i--; - src++; - dst++; + const __m128 floats = _mm_load_ss(src); + const __m128 values = _mm_mul_ss(floats, limit); + const __m128i ints = _mm_xor_si128(_mm_cvttps_epi32(values), _mm_castps_si128(_mm_cmpge_ss(values, limit))); + *dst = (Sint32)_mm_cvtsi128_si32(ints); + + --i; + ++src; + ++dst; } } #endif