From 52f82846e651d240f6e610f91bc63b3ee74b3d44 Mon Sep 17 00:00:00 2001 From: Benjamin Poulain Date: Fri, 10 Sep 2010 21:51:13 +0200 Subject: Remove the memory safety for the first scanline of the SSSE3 blending MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Memory is allocated on 16 bytes boundaries. We can do the aligned load without risking a invalid memory access. This simplify the code. Reviewed-by: Samuel Rødal --- src/gui/painting/qdrawhelper_ssse3.cpp | 75 ++-------------------------------- 1 file changed, 3 insertions(+), 72 deletions(-) diff --git a/src/gui/painting/qdrawhelper_ssse3.cpp b/src/gui/painting/qdrawhelper_ssse3.cpp index 4cb4089..fb5602e 100644 --- a/src/gui/painting/qdrawhelper_ssse3.cpp +++ b/src/gui/painting/qdrawhelper_ssse3.cpp @@ -79,69 +79,6 @@ inline static void blend_pixel(quint32 &dst, const quint32 src) } -#define BLEND_SOURCE_OVER_ARGB32_FIRST_ROW_SSSE3(dst, src, length, nullVector, half, one, colorMask, alphaMask) { \ - int x = 0; \ -\ - /* First, get dst aligned. */ \ - const int offsetToAlignOn16Bytes = (4 - ((reinterpret_cast(dst) >> 2) & 0x3)) & 0x3;\ - const int prologLength = qMin(length, offsetToAlignOn16Bytes);\ -\ - for (; x < prologLength; ++x) {\ - blend_pixel(dst[x], src[x]); \ - } \ -\ - const int minusOffsetToAlignSrcOn16Bytes = (reinterpret_cast(&(src[x])) >> 2) & 0x3;\ -\ - if (!minusOffsetToAlignSrcOn16Bytes) {\ - /* src is aligned, usual algorithm but with aligned operations.\ - See the SSE2 version for more documentation on the algorithm itself. */\ - const __m128i alphaShuffleMask = _mm_set_epi8(0xff,15,0xff,15,0xff,11,0xff,11,0xff,7,0xff,7,0xff,3,0xff,3);\ - for (; x < length-3; x += 4) { \ - const __m128i srcVector = _mm_load_si128((__m128i *)&src[x]); \ - const __m128i srcVectorAlpha = _mm_and_si128(srcVector, alphaMask); \ - if (_mm_movemask_epi8(_mm_cmpeq_epi32(srcVectorAlpha, alphaMask)) == 0xffff) { \ - _mm_store_si128((__m128i *)&dst[x], srcVector); \ - } else if (_mm_movemask_epi8(_mm_cmpeq_epi32(srcVectorAlpha, nullVector)) != 0xffff) { \ - __m128i alphaChannel = _mm_shuffle_epi8(srcVector, alphaShuffleMask); \ - alphaChannel = _mm_sub_epi16(one, alphaChannel); \ - const __m128i dstVector = _mm_load_si128((__m128i *)&dst[x]); \ - __m128i destMultipliedByOneMinusAlpha; \ - BYTE_MUL_SSE2(destMultipliedByOneMinusAlpha, dstVector, alphaChannel, colorMask, half); \ - const __m128i result = _mm_add_epi8(srcVector, destMultipliedByOneMinusAlpha); \ - _mm_store_si128((__m128i *)&dst[x], result); \ - } \ - } /* end for() */\ - } else if ((length - x) >= 8) {\ - /* We are at the first line, so "x - minusOffsetToAlignSrcOn16Bytes" could go before src, and\ - generate an invalid access. */\ -\ - /* We use two vectors to extract the src: prevLoaded for the first pixels, lastLoaded for the current pixels. */\ - __m128i srcVectorPrevLoaded;\ - if (minusOffsetToAlignSrcOn16Bytes > prologLength) {\ - /* We go forward 4 pixels to avoid reading before src. */\ - for (; x < prologLength + 4; ++x)\ - blend_pixel(dst[x], src[x]); \ - }\ - srcVectorPrevLoaded = _mm_load_si128((__m128i *)&src[x - minusOffsetToAlignSrcOn16Bytes]);\ - const int palignrOffset = minusOffsetToAlignSrcOn16Bytes << 2;\ -\ - const __m128i alphaShuffleMask = _mm_set_epi8(0xff,15,0xff,15,0xff,11,0xff,11,0xff,7,0xff,7,0xff,3,0xff,3);\ - switch (palignrOffset) {\ - case 4:\ - BLENDING_LOOP(4, length)\ - break;\ - case 8:\ - BLENDING_LOOP(8, length)\ - break;\ - case 12:\ - BLENDING_LOOP(12, length)\ - break;\ - }\ - }\ - for (; x < length; ++x) \ - blend_pixel(dst[x], src[x]); \ -} - // Basically blend src over dst with the const alpha defined as constAlphaVector. // nullVector, half, one, colorMask are constant accross the whole image/texture, and should be defined as: //const __m128i nullVector = _mm_set1_epi32(0); @@ -153,7 +90,7 @@ inline static void blend_pixel(quint32 &dst, const quint32 src) // The computation being done is: // result = s + d * (1-alpha) // with shortcuts if fully opaque or fully transparent. -#define BLEND_SOURCE_OVER_ARGB32_MAIN_SSSE3(dst, src, length, nullVector, half, one, colorMask, alphaMask) { \ +#define BLEND_SOURCE_OVER_ARGB32_SSSE3(dst, src, length, nullVector, half, one, colorMask, alphaMask) { \ int x = 0; \ \ /* First, get dst aligned. */ \ @@ -218,14 +155,8 @@ void qt_blend_argb32_on_argb32_ssse3(uchar *destPixels, int dbpl, const __m128i one = _mm_set1_epi16(0xff); const __m128i colorMask = _mm_set1_epi32(0x00ff00ff); - // We have to unrol the first row in order to deal with the load on unaligned data - // prior to the src pointer. - BLEND_SOURCE_OVER_ARGB32_FIRST_ROW_SSSE3(dst, src, w, nullVector, half, one, colorMask, alphaMask); - dst = (quint32 *)(((uchar *) dst) + dbpl); - src = (const quint32 *)(((const uchar *) src) + sbpl); - - for (int y = 1; y < h; ++y) { - BLEND_SOURCE_OVER_ARGB32_MAIN_SSSE3(dst, src, w, nullVector, half, one, colorMask, alphaMask); + for (int y = 0; y < h; ++y) { + BLEND_SOURCE_OVER_ARGB32_SSSE3(dst, src, w, nullVector, half, one, colorMask, alphaMask); dst = (quint32 *)(((uchar *) dst) + dbpl); src = (const quint32 *)(((const uchar *) src) + sbpl); } -- cgit v0.12