1 /* 2 * Copyright 2014 The Android Open Source Project 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkMath_opts_SSE2_DEFINED 9 #define SkMath_opts_SSE2_DEFINED 10 11 #include <emmintrin.h> 12 13 // Because no _mm_div_epi32() in SSE2, we use float division to emulate. 14 // When using this function, make sure a and b don't exceed float's precision. 15 static inline __m128i shim_mm_div_epi32(const __m128i& a, const __m128i& b) { 16 __m128 x = _mm_cvtepi32_ps(a); 17 __m128 y = _mm_cvtepi32_ps(b); 18 return _mm_cvttps_epi32(_mm_div_ps(x, y)); 19 } 20 21 // Portable version of SkSqrtBits is in SkMath.cpp. 22 static inline __m128i SkSqrtBits_SSE2(const __m128i& x, int count) { 23 __m128i root = _mm_setzero_si128(); 24 __m128i remHi = _mm_setzero_si128(); 25 __m128i remLo = x; 26 __m128i one128 = _mm_set1_epi32(1); 27 28 do { 29 root = _mm_slli_epi32(root, 1); 30 31 remHi = _mm_or_si128(_mm_slli_epi32(remHi, 2), 32 _mm_srli_epi32(remLo, 30)); 33 remLo = _mm_slli_epi32(remLo, 2); 34 35 __m128i testDiv = _mm_slli_epi32(root, 1); 36 testDiv = _mm_add_epi32(testDiv, _mm_set1_epi32(1)); 37 38 __m128i cmp = _mm_cmplt_epi32(remHi, testDiv); 39 __m128i remHi1 = _mm_and_si128(cmp, remHi); 40 __m128i root1 = _mm_and_si128(cmp, root); 41 __m128i remHi2 = _mm_andnot_si128(cmp, _mm_sub_epi32(remHi, testDiv)); 42 __m128i root2 = _mm_andnot_si128(cmp, _mm_add_epi32(root, one128)); 43 44 remHi = _mm_or_si128(remHi1, remHi2); 45 root = _mm_or_si128(root1, root2); 46 } while (--count >= 0); 47 48 return root; 49 } 50 51 #endif // SkMath_opts_SSE2_DEFINED 52
