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/*
* jccolext-neon.c - colorspace conversion (64-bit Arm Neon)
*
* Copyright (C) 2020, Arm Limited. All Rights Reserved.
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
/* This file is included by jccolor-neon.c */
/* RGB -> YCbCr conversion is defined by the following equations:
* Y = 0.29900 * R + 0.58700 * G + 0.11400 * B
* Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + 128
* Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + 128
*
* Avoid floating point arithmetic by using shifted integer constants:
* 0.29899597 = 19595 * 2^-16
* 0.58700561 = 38470 * 2^-16
* 0.11399841 = 7471 * 2^-16
* 0.16874695 = 11059 * 2^-16
* 0.33125305 = 21709 * 2^-16
* 0.50000000 = 32768 * 2^-16
* 0.41868592 = 27439 * 2^-16
* 0.08131409 = 5329 * 2^-16
* These constants are defined in jccolor-neon.c
*
* We add the fixed-point equivalent of 0.5 to Cb and Cr, which effectively
* rounds up or down the result via integer truncation.
*/
void jsimd_rgb_ycc_convert_neon(JDIMENSION image_width, JSAMPARRAY input_buf,
JSAMPIMAGE output_buf, JDIMENSION output_row,
int num_rows)
{
/* Pointer to RGB(X/A) input data */
JSAMPROW inptr;
/* Pointers to Y, Cb, and Cr output data */
JSAMPROW outptr0, outptr1, outptr2;
/* Allocate temporary buffer for final (image_width % 16) pixels in row. */
ALIGN(16) uint8_t tmp_buf[16 * RGB_PIXELSIZE];
/* Set up conversion constants. */
const uint16x8_t consts = vld1q_u16(jsimd_rgb_ycc_neon_consts);
const uint32x4_t scaled_128_5 = vdupq_n_u32((128 << 16) + 32767);
while (--num_rows >= 0) {
inptr = *input_buf++;
outptr0 = output_buf[0][output_row];
outptr1 = output_buf[1][output_row];
outptr2 = output_buf[2][output_row];
output_row++;
int cols_remaining = image_width;
for (; cols_remaining >= 16; cols_remaining -= 16) {
#if RGB_PIXELSIZE == 4
uint8x16x4_t input_pixels = vld4q_u8(inptr);
#else
uint8x16x3_t input_pixels = vld3q_u8(inptr);
#endif
uint16x8_t r_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_RED]));
uint16x8_t g_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_GREEN]));
uint16x8_t b_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_BLUE]));
uint16x8_t r_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_RED]));
uint16x8_t g_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_GREEN]));
uint16x8_t b_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_BLUE]));
/* Compute Y = 0.29900 * R + 0.58700 * G + 0.11400 * B */
uint32x4_t y_ll = vmull_laneq_u16(vget_low_u16(r_l), consts, 0);
y_ll = vmlal_laneq_u16(y_ll, vget_low_u16(g_l), consts, 1);
y_ll = vmlal_laneq_u16(y_ll, vget_low_u16(b_l), consts, 2);
uint32x4_t y_lh = vmull_laneq_u16(vget_high_u16(r_l), consts, 0);
y_lh = vmlal_laneq_u16(y_lh, vget_high_u16(g_l), consts, 1);
y_lh = vmlal_laneq_u16(y_lh, vget_high_u16(b_l), consts, 2);
uint32x4_t y_hl = vmull_laneq_u16(vget_low_u16(r_h), consts, 0);
y_hl = vmlal_laneq_u16(y_hl, vget_low_u16(g_h), consts, 1);
y_hl = vmlal_laneq_u16(y_hl, vget_low_u16(b_h), consts, 2);
uint32x4_t y_hh = vmull_laneq_u16(vget_high_u16(r_h), consts, 0);
y_hh = vmlal_laneq_u16(y_hh, vget_high_u16(g_h), consts, 1);
y_hh = vmlal_laneq_u16(y_hh, vget_high_u16(b_h), consts, 2);
/* Compute Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + 128 */
uint32x4_t cb_ll = scaled_128_5;
cb_ll = vmlsl_laneq_u16(cb_ll, vget_low_u16(r_l), consts, 3);
cb_ll = vmlsl_laneq_u16(cb_ll, vget_low_u16(g_l), consts, 4);
cb_ll = vmlal_laneq_u16(cb_ll, vget_low_u16(b_l), consts, 5);
uint32x4_t cb_lh = scaled_128_5;
cb_lh = vmlsl_laneq_u16(cb_lh, vget_high_u16(r_l), consts, 3);
cb_lh = vmlsl_laneq_u16(cb_lh, vget_high_u16(g_l), consts, 4);
cb_lh = vmlal_laneq_u16(cb_lh, vget_high_u16(b_l), consts, 5);
uint32x4_t cb_hl = scaled_128_5;
cb_hl = vmlsl_laneq_u16(cb_hl, vget_low_u16(r_h), consts, 3);
cb_hl = vmlsl_laneq_u16(cb_hl, vget_low_u16(g_h), consts, 4);
cb_hl = vmlal_laneq_u16(cb_hl, vget_low_u16(b_h), consts, 5);
uint32x4_t cb_hh = scaled_128_5;
cb_hh = vmlsl_laneq_u16(cb_hh, vget_high_u16(r_h), consts, 3);
cb_hh = vmlsl_laneq_u16(cb_hh, vget_high_u16(g_h), consts, 4);
cb_hh = vmlal_laneq_u16(cb_hh, vget_high_u16(b_h), consts, 5);
/* Compute Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + 128 */
uint32x4_t cr_ll = scaled_128_5;
cr_ll = vmlal_laneq_u16(cr_ll, vget_low_u16(r_l), consts, 5);
cr_ll = vmlsl_laneq_u16(cr_ll, vget_low_u16(g_l), consts, 6);
cr_ll = vmlsl_laneq_u16(cr_ll, vget_low_u16(b_l), consts, 7);
uint32x4_t cr_lh = scaled_128_5;
cr_lh = vmlal_laneq_u16(cr_lh, vget_high_u16(r_l), consts, 5);
cr_lh = vmlsl_laneq_u16(cr_lh, vget_high_u16(g_l), consts, 6);
cr_lh = vmlsl_laneq_u16(cr_lh, vget_high_u16(b_l), consts, 7);
uint32x4_t cr_hl = scaled_128_5;
cr_hl = vmlal_laneq_u16(cr_hl, vget_low_u16(r_h), consts, 5);
cr_hl = vmlsl_laneq_u16(cr_hl, vget_low_u16(g_h), consts, 6);
cr_hl = vmlsl_laneq_u16(cr_hl, vget_low_u16(b_h), consts, 7);
uint32x4_t cr_hh = scaled_128_5;
cr_hh = vmlal_laneq_u16(cr_hh, vget_high_u16(r_h), consts, 5);
cr_hh = vmlsl_laneq_u16(cr_hh, vget_high_u16(g_h), consts, 6);
cr_hh = vmlsl_laneq_u16(cr_hh, vget_high_u16(b_h), consts, 7);
/* Descale Y values (rounding right shift) and narrow to 16-bit. */
uint16x8_t y_l = vcombine_u16(vrshrn_n_u32(y_ll, 16),
vrshrn_n_u32(y_lh, 16));
uint16x8_t y_h = vcombine_u16(vrshrn_n_u32(y_hl, 16),
vrshrn_n_u32(y_hh, 16));
/* Descale Cb values (right shift) and narrow to 16-bit. */
uint16x8_t cb_l = vcombine_u16(vshrn_n_u32(cb_ll, 16),
vshrn_n_u32(cb_lh, 16));
uint16x8_t cb_h = vcombine_u16(vshrn_n_u32(cb_hl, 16),
vshrn_n_u32(cb_hh, 16));
/* Descale Cr values (right shift) and narrow to 16-bit. */
uint16x8_t cr_l = vcombine_u16(vshrn_n_u32(cr_ll, 16),
vshrn_n_u32(cr_lh, 16));
uint16x8_t cr_h = vcombine_u16(vshrn_n_u32(cr_hl, 16),
vshrn_n_u32(cr_hh, 16));
/* Narrow Y, Cb, and Cr values to 8-bit and store to memory. Buffer
* overwrite is permitted up to the next multiple of ALIGN_SIZE bytes.
*/
vst1q_u8(outptr0, vcombine_u8(vmovn_u16(y_l), vmovn_u16(y_h)));
vst1q_u8(outptr1, vcombine_u8(vmovn_u16(cb_l), vmovn_u16(cb_h)));
vst1q_u8(outptr2, vcombine_u8(vmovn_u16(cr_l), vmovn_u16(cr_h)));
/* Increment pointers. */
inptr += (16 * RGB_PIXELSIZE);
outptr0 += 16;
outptr1 += 16;
outptr2 += 16;
}
if (cols_remaining > 8) {
/* To prevent buffer overread by the vector load instructions, the last
* (image_width % 16) columns of data are first memcopied to a temporary
* buffer large enough to accommodate the vector load.
*/
memcpy(tmp_buf, inptr, cols_remaining * RGB_PIXELSIZE);
inptr = tmp_buf;
#if RGB_PIXELSIZE == 4
uint8x16x4_t input_pixels = vld4q_u8(inptr);
#else
uint8x16x3_t input_pixels = vld3q_u8(inptr);
#endif
uint16x8_t r_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_RED]));
uint16x8_t g_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_GREEN]));
uint16x8_t b_l = vmovl_u8(vget_low_u8(input_pixels.val[RGB_BLUE]));
uint16x8_t r_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_RED]));
uint16x8_t g_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_GREEN]));
uint16x8_t b_h = vmovl_u8(vget_high_u8(input_pixels.val[RGB_BLUE]));
/* Compute Y = 0.29900 * R + 0.58700 * G + 0.11400 * B */
uint32x4_t y_ll = vmull_laneq_u16(vget_low_u16(r_l), consts, 0);
y_ll = vmlal_laneq_u16(y_ll, vget_low_u16(g_l), consts, 1);
y_ll = vmlal_laneq_u16(y_ll, vget_low_u16(b_l), consts, 2);
uint32x4_t y_lh = vmull_laneq_u16(vget_high_u16(r_l), consts, 0);
y_lh = vmlal_laneq_u16(y_lh, vget_high_u16(g_l), consts, 1);
y_lh = vmlal_laneq_u16(y_lh, vget_high_u16(b_l), consts, 2);
uint32x4_t y_hl = vmull_laneq_u16(vget_low_u16(r_h), consts, 0);
y_hl = vmlal_laneq_u16(y_hl, vget_low_u16(g_h), consts, 1);
y_hl = vmlal_laneq_u16(y_hl, vget_low_u16(b_h), consts, 2);
uint32x4_t y_hh = vmull_laneq_u16(vget_high_u16(r_h), consts, 0);
y_hh = vmlal_laneq_u16(y_hh, vget_high_u16(g_h), consts, 1);
y_hh = vmlal_laneq_u16(y_hh, vget_high_u16(b_h), consts, 2);
/* Compute Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + 128 */
uint32x4_t cb_ll = scaled_128_5;
cb_ll = vmlsl_laneq_u16(cb_ll, vget_low_u16(r_l), consts, 3);
cb_ll = vmlsl_laneq_u16(cb_ll, vget_low_u16(g_l), consts, 4);
cb_ll = vmlal_laneq_u16(cb_ll, vget_low_u16(b_l), consts, 5);
uint32x4_t cb_lh = scaled_128_5;
cb_lh = vmlsl_laneq_u16(cb_lh, vget_high_u16(r_l), consts, 3);
cb_lh = vmlsl_laneq_u16(cb_lh, vget_high_u16(g_l), consts, 4);
cb_lh = vmlal_laneq_u16(cb_lh, vget_high_u16(b_l), consts, 5);
uint32x4_t cb_hl = scaled_128_5;
cb_hl = vmlsl_laneq_u16(cb_hl, vget_low_u16(r_h), consts, 3);
cb_hl = vmlsl_laneq_u16(cb_hl, vget_low_u16(g_h), consts, 4);
cb_hl = vmlal_laneq_u16(cb_hl, vget_low_u16(b_h), consts, 5);
uint32x4_t cb_hh = scaled_128_5;
cb_hh = vmlsl_laneq_u16(cb_hh, vget_high_u16(r_h), consts, 3);
cb_hh = vmlsl_laneq_u16(cb_hh, vget_high_u16(g_h), consts, 4);
cb_hh = vmlal_laneq_u16(cb_hh, vget_high_u16(b_h), consts, 5);
/* Compute Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + 128 */
uint32x4_t cr_ll = scaled_128_5;
cr_ll = vmlal_laneq_u16(cr_ll, vget_low_u16(r_l), consts, 5);
cr_ll = vmlsl_laneq_u16(cr_ll, vget_low_u16(g_l), consts, 6);
cr_ll = vmlsl_laneq_u16(cr_ll, vget_low_u16(b_l), consts, 7);
uint32x4_t cr_lh = scaled_128_5;
cr_lh = vmlal_laneq_u16(cr_lh, vget_high_u16(r_l), consts, 5);
cr_lh = vmlsl_laneq_u16(cr_lh, vget_high_u16(g_l), consts, 6);
cr_lh = vmlsl_laneq_u16(cr_lh, vget_high_u16(b_l), consts, 7);
uint32x4_t cr_hl = scaled_128_5;
cr_hl = vmlal_laneq_u16(cr_hl, vget_low_u16(r_h), consts, 5);
cr_hl = vmlsl_laneq_u16(cr_hl, vget_low_u16(g_h), consts, 6);
cr_hl = vmlsl_laneq_u16(cr_hl, vget_low_u16(b_h), consts, 7);
uint32x4_t cr_hh = scaled_128_5;
cr_hh = vmlal_laneq_u16(cr_hh, vget_high_u16(r_h), consts, 5);
cr_hh = vmlsl_laneq_u16(cr_hh, vget_high_u16(g_h), consts, 6);
cr_hh = vmlsl_laneq_u16(cr_hh, vget_high_u16(b_h), consts, 7);
/* Descale Y values (rounding right shift) and narrow to 16-bit. */
uint16x8_t y_l = vcombine_u16(vrshrn_n_u32(y_ll, 16),
vrshrn_n_u32(y_lh, 16));
uint16x8_t y_h = vcombine_u16(vrshrn_n_u32(y_hl, 16),
vrshrn_n_u32(y_hh, 16));
/* Descale Cb values (right shift) and narrow to 16-bit. */
uint16x8_t cb_l = vcombine_u16(vshrn_n_u32(cb_ll, 16),
vshrn_n_u32(cb_lh, 16));
uint16x8_t cb_h = vcombine_u16(vshrn_n_u32(cb_hl, 16),
vshrn_n_u32(cb_hh, 16));
/* Descale Cr values (right shift) and narrow to 16-bit. */
uint16x8_t cr_l = vcombine_u16(vshrn_n_u32(cr_ll, 16),
vshrn_n_u32(cr_lh, 16));
uint16x8_t cr_h = vcombine_u16(vshrn_n_u32(cr_hl, 16),
vshrn_n_u32(cr_hh, 16));
/* Narrow Y, Cb, and Cr values to 8-bit and store to memory. Buffer
* overwrite is permitted up to the next multiple of ALIGN_SIZE bytes.
*/
vst1q_u8(outptr0, vcombine_u8(vmovn_u16(y_l), vmovn_u16(y_h)));
vst1q_u8(outptr1, vcombine_u8(vmovn_u16(cb_l), vmovn_u16(cb_h)));
vst1q_u8(outptr2, vcombine_u8(vmovn_u16(cr_l), vmovn_u16(cr_h)));
} else if (cols_remaining > 0) {
/* To prevent buffer overread by the vector load instructions, the last
* (image_width % 8) columns of data are first memcopied to a temporary
* buffer large enough to accommodate the vector load.
*/
memcpy(tmp_buf, inptr, cols_remaining * RGB_PIXELSIZE);
inptr = tmp_buf;
#if RGB_PIXELSIZE == 4
uint8x8x4_t input_pixels = vld4_u8(inptr);
#else
uint8x8x3_t input_pixels = vld3_u8(inptr);
#endif
uint16x8_t r = vmovl_u8(input_pixels.val[RGB_RED]);
uint16x8_t g = vmovl_u8(input_pixels.val[RGB_GREEN]);
uint16x8_t b = vmovl_u8(input_pixels.val[RGB_BLUE]);
/* Compute Y = 0.29900 * R + 0.58700 * G + 0.11400 * B */
uint32x4_t y_l = vmull_laneq_u16(vget_low_u16(r), consts, 0);
y_l = vmlal_laneq_u16(y_l, vget_low_u16(g), consts, 1);
y_l = vmlal_laneq_u16(y_l, vget_low_u16(b), consts, 2);
uint32x4_t y_h = vmull_laneq_u16(vget_high_u16(r), consts, 0);
y_h = vmlal_laneq_u16(y_h, vget_high_u16(g), consts, 1);
y_h = vmlal_laneq_u16(y_h, vget_high_u16(b), consts, 2);
/* Compute Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + 128 */
uint32x4_t cb_l = scaled_128_5;
cb_l = vmlsl_laneq_u16(cb_l, vget_low_u16(r), consts, 3);
cb_l = vmlsl_laneq_u16(cb_l, vget_low_u16(g), consts, 4);
cb_l = vmlal_laneq_u16(cb_l, vget_low_u16(b), consts, 5);
uint32x4_t cb_h = scaled_128_5;
cb_h = vmlsl_laneq_u16(cb_h, vget_high_u16(r), consts, 3);
cb_h = vmlsl_laneq_u16(cb_h, vget_high_u16(g), consts, 4);
cb_h = vmlal_laneq_u16(cb_h, vget_high_u16(b), consts, 5);
/* Compute Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + 128 */
uint32x4_t cr_l = scaled_128_5;
cr_l = vmlal_laneq_u16(cr_l, vget_low_u16(r), consts, 5);
cr_l = vmlsl_laneq_u16(cr_l, vget_low_u16(g), consts, 6);
cr_l = vmlsl_laneq_u16(cr_l, vget_low_u16(b), consts, 7);
uint32x4_t cr_h = scaled_128_5;
cr_h = vmlal_laneq_u16(cr_h, vget_high_u16(r), consts, 5);
cr_h = vmlsl_laneq_u16(cr_h, vget_high_u16(g), consts, 6);
cr_h = vmlsl_laneq_u16(cr_h, vget_high_u16(b), consts, 7);
/* Descale Y values (rounding right shift) and narrow to 16-bit. */
uint16x8_t y_u16 = vcombine_u16(vrshrn_n_u32(y_l, 16),
vrshrn_n_u32(y_h, 16));
/* Descale Cb values (right shift) and narrow to 16-bit. */
uint16x8_t cb_u16 = vcombine_u16(vshrn_n_u32(cb_l, 16),
vshrn_n_u32(cb_h, 16));
/* Descale Cr values (right shift) and narrow to 16-bit. */
uint16x8_t cr_u16 = vcombine_u16(vshrn_n_u32(cr_l, 16),
vshrn_n_u32(cr_h, 16));
/* Narrow Y, Cb, and Cr values to 8-bit and store to memory. Buffer
* overwrite is permitted up to the next multiple of ALIGN_SIZE bytes.
*/
vst1_u8(outptr0, vmovn_u16(y_u16));
vst1_u8(outptr1, vmovn_u16(cb_u16));
vst1_u8(outptr2, vmovn_u16(cr_u16));
}
}
}
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