/* palette_neon_intrinsics.c - NEON optimised palette expansion functions * * Copyright (c) 2018-2019 Cosmin Truta * Copyright (c) 2017-2018 Arm Holdings. All rights reserved. * Written by Richard Townsend <Richard.Townsend@arm.com>, February 2017. * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h */ #include "../pngpriv.h" #if PNG_ARM_NEON_IMPLEMENTATION == 1 #if defined(_MSC_VER) && defined(_M_ARM64) # include <arm64_neon.h> #else # include <arm_neon.h> #endif /* Build an RGBA8 palette from the separate RGB and alpha palettes. */ void png_riffle_palette_neon(png_structrp png_ptr) { png_const_colorp palette = png_ptr->palette; png_bytep riffled_palette = png_ptr->riffled_palette; png_const_bytep trans_alpha = png_ptr->trans_alpha; int num_trans = png_ptr->num_trans; int i; png_debug(1, "in png_riffle_palette_neon"); /* Initially black, opaque. */ uint8x16x4_t w = {{ vdupq_n_u8(0x00), vdupq_n_u8(0x00), vdupq_n_u8(0x00), vdupq_n_u8(0xff), }}; /* First, riffle the RGB colours into an RGBA8 palette. * The alpha component is set to opaque for now. */ for (i = 0; i < 256; i += 16) { uint8x16x3_t v = vld3q_u8((png_const_bytep)(palette + i)); w.val[0] = v.val[0]; w.val[1] = v.val[1]; w.val[2] = v.val[2]; vst4q_u8(riffled_palette + (i << 2), w); } /* Fix up the missing transparency values. */ for (i = 0; i < num_trans; i++) riffled_palette[(i << 2) + 3] = trans_alpha[i]; } /* Expands a palettized row into RGBA8. */ int png_do_expand_palette_rgba8_neon(png_structrp png_ptr, png_row_infop row_info, png_const_bytep row, png_bytepp ssp, png_bytepp ddp) { png_uint_32 row_width = row_info->width; const png_uint_32 *riffled_palette = (const png_uint_32 *)png_ptr->riffled_palette; const png_int_32 pixels_per_chunk = 4; int i; png_debug(1, "in png_do_expand_palette_rgba8_neon"); if (row_width < pixels_per_chunk) return 0; /* This function originally gets the last byte of the output row. * The NEON part writes forward from a given position, so we have * to seek this back by 4 pixels x 4 bytes. */ *ddp = *ddp - ((pixels_per_chunk * sizeof(png_uint_32)) - 1); for (i = 0; i < row_width; i += pixels_per_chunk) { uint32x4_t cur; png_bytep sp = *ssp - i, dp = *ddp - (i << 2); cur = vld1q_dup_u32 (riffled_palette + *(sp - 3)); cur = vld1q_lane_u32(riffled_palette + *(sp - 2), cur, 1); cur = vld1q_lane_u32(riffled_palette + *(sp - 1), cur, 2); cur = vld1q_lane_u32(riffled_palette + *(sp - 0), cur, 3); vst1q_u32((void *)dp, cur); } if (i != row_width) { /* Remove the amount that wasn't processed. */ i -= pixels_per_chunk; } /* Decrement output pointers. */ *ssp = *ssp - i; *ddp = *ddp - (i << 2); return i; } /* Expands a palettized row into RGB8. */ int png_do_expand_palette_rgb8_neon(png_structrp png_ptr, png_row_infop row_info, png_const_bytep row, png_bytepp ssp, png_bytepp ddp) { png_uint_32 row_width = row_info->width; png_const_bytep palette = (png_const_bytep)png_ptr->palette; const png_uint_32 pixels_per_chunk = 8; int i; png_debug(1, "in png_do_expand_palette_rgb8_neon"); if (row_width <= pixels_per_chunk) return 0; /* Seeking this back by 8 pixels x 3 bytes. */ *ddp = *ddp - ((pixels_per_chunk * sizeof(png_color)) - 1); for (i = 0; i < row_width; i += pixels_per_chunk) { uint8x8x3_t cur; png_bytep sp = *ssp - i, dp = *ddp - ((i << 1) + i); cur = vld3_dup_u8(palette + sizeof(png_color) * (*(sp - 7))); cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 6)), cur, 1); cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 5)), cur, 2); cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 4)), cur, 3); cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 3)), cur, 4); cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 2)), cur, 5); cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 1)), cur, 6); cur = vld3_lane_u8(palette + sizeof(png_color) * (*(sp - 0)), cur, 7); vst3_u8((void *)dp, cur); } if (i != row_width) { /* Remove the amount that wasn't processed. */ i -= pixels_per_chunk; } /* Decrement output pointers. */ *ssp = *ssp - i; *ddp = *ddp - ((i << 1) + i); return i; } #endif /* PNG_ARM_NEON_IMPLEMENTATION */