eb14189caa
- Use the _M_ARM and _M_ARM64 macros provided by Visual Studio for compile-time detection of Arm builds, since __arm__ and __aarch64__ are only present in GNU-compatible compilers. - Neon/intrinsics: Use the _CountLeadingZeros() and _CountLeadingZeros64() intrinsics provided by Visual Studio, since __builtin_clz() and __builtin_clzl() are only present in GNU-compatible compilers. - Neon/intrinsics: Since Visual Studio does not support static vector initialization, replace static initialization of Neon vectors with the appropriate intrinsics. Compared to the static initialization approach, this produces identical assembly code with both GCC and Clang. - Neon/intrinsics: Since Visual Studio does not support inline assembly code, provide alternative code paths for Visual Studio whenever inline assembly is used. - Build: Set FLOATTEST appropriately for AArch64 Visual Studio builds (Visual Studio does not emit fused multiply-add [FMA] instructions by default for such builds.) - Neon/intrinsics: Move temporary buffer allocation outside of nested loops. Since Visual Studio configures Arm builds with a relatively small amount of stack memory, attempting to allocate those buffers within the inner loops caused a stack overflow. Closes #461 Closes #475
107 lines
4.3 KiB
C
107 lines
4.3 KiB
C
/*
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* jcgryext-neon.c - grayscale colorspace conversion (Arm Neon)
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*
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* Copyright (C) 2020, Arm Limited. All Rights Reserved.
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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*/
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/* This file is included by jcgray-neon.c */
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/* RGB -> Grayscale conversion is defined by the following equation:
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* Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
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*
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* Avoid floating point arithmetic by using shifted integer constants:
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* 0.29899597 = 19595 * 2^-16
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* 0.58700561 = 38470 * 2^-16
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* 0.11399841 = 7471 * 2^-16
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* These constants are defined in jcgray-neon.c
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*
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* This is the same computation as the RGB -> Y portion of RGB -> YCbCr.
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*/
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void jsimd_rgb_gray_convert_neon(JDIMENSION image_width, JSAMPARRAY input_buf,
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JSAMPIMAGE output_buf, JDIMENSION output_row,
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int num_rows)
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{
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JSAMPROW inptr;
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JSAMPROW outptr;
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/* Allocate temporary buffer for final (image_width % 16) pixels in row. */
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ALIGN(16) uint8_t tmp_buf[16 * RGB_PIXELSIZE];
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while (--num_rows >= 0) {
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inptr = *input_buf++;
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outptr = output_buf[0][output_row];
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output_row++;
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int cols_remaining = image_width;
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for (; cols_remaining > 0; cols_remaining -= 16) {
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/* To prevent buffer overread by the vector load instructions, the last
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* (image_width % 16) columns of data are first memcopied to a temporary
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* buffer large enough to accommodate the vector load.
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*/
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if (cols_remaining < 16) {
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memcpy(tmp_buf, inptr, cols_remaining * RGB_PIXELSIZE);
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inptr = tmp_buf;
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}
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#if RGB_PIXELSIZE == 4
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uint8x16x4_t input_pixels = vld4q_u8(inptr);
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#else
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uint8x16x3_t input_pixels = vld3q_u8(inptr);
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#endif
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uint16x8_t r_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_RED]));
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uint16x8_t r_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_RED]));
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uint16x8_t g_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_GREEN]));
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uint16x8_t g_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_GREEN]));
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uint16x8_t b_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_BLUE]));
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uint16x8_t b_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_BLUE]));
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/* Compute Y = 0.29900 * R + 0.58700 * G + 0.11400 * B */
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uint32x4_t y_ll = vmull_n_u16(vget_low_u16(r_l), F_0_298);
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uint32x4_t y_lh = vmull_n_u16(vget_high_u16(r_l), F_0_298);
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uint32x4_t y_hl = vmull_n_u16(vget_low_u16(r_h), F_0_298);
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uint32x4_t y_hh = vmull_n_u16(vget_high_u16(r_h), F_0_298);
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y_ll = vmlal_n_u16(y_ll, vget_low_u16(g_l), F_0_587);
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y_lh = vmlal_n_u16(y_lh, vget_high_u16(g_l), F_0_587);
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y_hl = vmlal_n_u16(y_hl, vget_low_u16(g_h), F_0_587);
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y_hh = vmlal_n_u16(y_hh, vget_high_u16(g_h), F_0_587);
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y_ll = vmlal_n_u16(y_ll, vget_low_u16(b_l), F_0_113);
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y_lh = vmlal_n_u16(y_lh, vget_high_u16(b_l), F_0_113);
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y_hl = vmlal_n_u16(y_hl, vget_low_u16(b_h), F_0_113);
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y_hh = vmlal_n_u16(y_hh, vget_high_u16(b_h), F_0_113);
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/* Descale Y values (rounding right shift) and narrow to 16-bit. */
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uint16x8_t y_l = vcombine_u16(vrshrn_n_u32(y_ll, 16),
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vrshrn_n_u32(y_lh, 16));
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uint16x8_t y_h = vcombine_u16(vrshrn_n_u32(y_hl, 16),
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vrshrn_n_u32(y_hh, 16));
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/* Narrow Y values to 8-bit and store to memory. Buffer overwrite is
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* permitted up to the next multiple of ALIGN_SIZE bytes.
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*/
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vst1q_u8(outptr, vcombine_u8(vmovn_u16(y_l), vmovn_u16(y_h)));
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/* Increment pointers. */
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inptr += (16 * RGB_PIXELSIZE);
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outptr += 16;
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}
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}
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}
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