diff --git a/png/CMakeLists.txt b/png/CMakeLists.txt
index 6a94c6c28778075bda35e1fc2d67357b0edcb86c..b9988695b6665c54b783f2edd3283183dd6223f9 100644
--- a/png/CMakeLists.txt
+++ b/png/CMakeLists.txt
@@ -31,6 +31,9 @@ set(PNG_SRCS
pngwrite.c
pngwtran.c
pngwutil.c
+ arm/arm_init.c
+ arm/filter_neon_intrinsics.c
+ arm/palette_neon_intrinsics.c
)
#######################################################################
diff --git a/png/Makefile b/png/Makefile
index 80b13495016ed1462a93ac55c20dd45cc59e16d3..f444ebd368c078dcd9a649d98770e1b782d11183 100644
--- a/png/Makefile
+++ b/png/Makefile
@@ -23,7 +23,8 @@ include ../makeinclude
OBJS = png.o pngset.o pngget.o pngrutil.o pngtrans.o pngwutil.o \
pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
- pngwtran.o pngmem.o pngerror.o pngpread.o
+ pngwtran.o pngmem.o pngerror.o pngpread.o \
+ arm/arm_init.o arm/filter_neon_intrinsics.o arm/palette_neon_intrinsics.o
LIBPNG = ../lib/libfltk_png$(LIBEXT)
diff --git a/png/arm/arm_init.c b/png/arm/arm_init.c
new file mode 100644
index 0000000000000000000000000000000000000000..a34ecdbef7350a935f15aee8cfac6c75a75e4a87
--- /dev/null
+++ b/png/arm/arm_init.c
@@ -0,0 +1,136 @@
+
+/* arm_init.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
+ * called.
+ */
+#define _POSIX_SOURCE 1
+
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+#if PNG_ARM_NEON_OPT > 0
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
+/* WARNING: it is strongly recommended that you do not build libpng with
+ * run-time checks for CPU features if at all possible. In the case of the ARM
+ * NEON instructions there is no processor-specific way of detecting the
+ * presence of the required support, therefore run-time detection is extremely
+ * OS specific.
+ *
+ * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
+ * a fragment of C source code which defines the png_have_neon function. There
+ * are a number of implementations in contrib/arm-neon, but the only one that
+ * has partial support is contrib/arm-neon/linux.c - a generic Linux
+ * implementation which reads /proc/cpufino.
+ */
+#ifndef PNG_ARM_NEON_FILE
+# ifdef __linux__
+# define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
+# endif
+#endif
+
+#ifdef PNG_ARM_NEON_FILE
+
+#include <signal.h> /* for sig_atomic_t */
+static int png_have_neon(png_structp png_ptr);
+#include PNG_ARM_NEON_FILE
+
+#else /* PNG_ARM_NEON_FILE */
+# error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"
+#endif /* PNG_ARM_NEON_FILE */
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
+# error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
+#endif
+
+void
+png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
+{
+ /* The switch statement is compiled in for ARM_NEON_API, the call to
+ * png_have_neon is compiled in for ARM_NEON_CHECK. If both are defined
+ * the check is only performed if the API has not set the NEON option on
+ * or off explicitly. In this case the check controls what happens.
+ *
+ * If the CHECK is not compiled in and the option is UNSET the behavior prior
+ * to 1.6.7 was to use the NEON code - this was a bug caused by having the
+ * wrong order of the 'ON' and 'default' cases. UNSET now defaults to OFF,
+ * as documented in png.h
+ */
+ png_debug(1, "in png_init_filter_functions_neon");
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+ switch ((pp->options >> PNG_ARM_NEON) & 3)
+ {
+ case PNG_OPTION_UNSET:
+ /* Allow the run-time check to execute if it has been enabled -
+ * thus both API and CHECK can be turned on. If it isn't supported
+ * this case will fall through to the 'default' below, which just
+ * returns.
+ */
+#endif /* PNG_ARM_NEON_API_SUPPORTED */
+#ifdef PNG_ARM_NEON_CHECK_SUPPORTED
+ {
+ static volatile sig_atomic_t no_neon = -1; /* not checked */
+
+ if (no_neon < 0)
+ no_neon = !png_have_neon(pp);
+
+ if (no_neon)
+ return;
+ }
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+ break;
+#endif
+#endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
+
+#ifdef PNG_ARM_NEON_API_SUPPORTED
+ default: /* OFF or INVALID */
+ return;
+
+ case PNG_OPTION_ON:
+ /* Option turned on */
+ break;
+ }
+#endif
+
+ /* IMPORTANT: any new external functions used here must be declared using
+ * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the
+ * 'prefix' option to configure works:
+ *
+ * ./configure --with-libpng-prefix=foobar_
+ *
+ * Verify you have got this right by running the above command, doing a build
+ * and examining pngprefix.h; it must contain a #define for every external
+ * function you add. (Notice that this happens automatically for the
+ * initialization function.)
+ */
+ pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
+
+ if (bpp == 3)
+ {
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth3_neon;
+ }
+
+ else if (bpp == 4)
+ {
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth4_neon;
+ }
+}
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* READ */
diff --git a/png/arm/filter_neon_intrinsics.c b/png/arm/filter_neon_intrinsics.c
new file mode 100644
index 0000000000000000000000000000000000000000..553c0be21c1051b2b1a950a593dabb661b2742b1
--- /dev/null
+++ b/png/arm/filter_neon_intrinsics.c
@@ -0,0 +1,402 @@
+
+/* filter_neon_intrinsics.c - NEON optimised filter functions
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 2014,2016 Glenn Randers-Pehrson
+ * Written by James Yu <james.yu at linaro.org>, October 2013.
+ * Based on filter_neon.S, written by Mans Rullgard, 2011.
+ *
+ * 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"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -mfpu=neon on the command line: */
+#if PNG_ARM_NEON_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+#if defined(_MSC_VER) && defined(_M_ARM64)
+# include <arm64_neon.h>
+#else
+# include <arm_neon.h>
+#endif
+
+/* libpng row pointers are not necessarily aligned to any particular boundary,
+ * however this code will only work with appropriate alignment. arm/arm_init.c
+ * checks for this (and will not compile unless it is done). This code uses
+ * variants of png_aligncast to avoid compiler warnings.
+ */
+#define png_ptr(type,pointer) png_aligncast(type *,pointer)
+#define png_ptrc(type,pointer) png_aligncastconst(const type *,pointer)
+
+/* The following relies on a variable 'temp_pointer' being declared with type
+ * 'type'. This is written this way just to hide the GCC strict aliasing
+ * warning; note that the code is safe because there never is an alias between
+ * the input and output pointers.
+ *
+ * When compiling with MSVC ARM64, the png_ldr macro can't be passed directly
+ * to vst4_lane_u32, because of an internal compiler error inside MSVC.
+ * To avoid this compiler bug, we use a temporary variable (vdest_val) to store
+ * the result of png_ldr.
+ */
+#define png_ldr(type,pointer)\
+ (temp_pointer = png_ptr(type,pointer), *temp_pointer)
+
+#if PNG_ARM_NEON_OPT > 0
+
+void
+png_read_filter_row_up_neon(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp = row;
+ png_bytep rp_stop = row + row_info->rowbytes;
+ png_const_bytep pp = prev_row;
+
+ png_debug(1, "in png_read_filter_row_up_neon");
+
+ for (; rp < rp_stop; rp += 16, pp += 16)
+ {
+ uint8x16_t qrp, qpp;
+
+ qrp = vld1q_u8(rp);
+ qpp = vld1q_u8(pp);
+ qrp = vaddq_u8(qrp, qpp);
+ vst1q_u8(rp, qrp);
+ }
+}
+
+void
+png_read_filter_row_sub3_neon(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp = row;
+ png_bytep rp_stop = row + row_info->rowbytes;
+
+ uint8x16_t vtmp = vld1q_u8(rp);
+ uint8x8x2_t *vrpt = png_ptr(uint8x8x2_t, &vtmp);
+ uint8x8x2_t vrp = *vrpt;
+
+ uint8x8x4_t vdest;
+ vdest.val[3] = vdup_n_u8(0);
+
+ png_debug(1, "in png_read_filter_row_sub3_neon");
+
+ for (; rp < rp_stop;)
+ {
+ uint8x8_t vtmp1, vtmp2;
+ uint32x2_t *temp_pointer;
+
+ vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+ vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+ vtmp2 = vext_u8(vrp.val[0], vrp.val[1], 6);
+ vdest.val[1] = vadd_u8(vdest.val[0], vtmp1);
+
+ vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+ vdest.val[2] = vadd_u8(vdest.val[1], vtmp2);
+ vdest.val[3] = vadd_u8(vdest.val[2], vtmp1);
+
+ vtmp = vld1q_u8(rp + 12);
+ vrpt = png_ptr(uint8x8x2_t, &vtmp);
+ vrp = *vrpt;
+
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+ rp += 3;
+ }
+
+ PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_sub4_neon(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp = row;
+ png_bytep rp_stop = row + row_info->rowbytes;
+
+ uint8x8x4_t vdest;
+ vdest.val[3] = vdup_n_u8(0);
+
+ png_debug(1, "in png_read_filter_row_sub4_neon");
+
+ for (; rp < rp_stop; rp += 16)
+ {
+ uint32x2x4_t vtmp = vld4_u32(png_ptr(uint32_t,rp));
+ uint8x8x4_t *vrpt = png_ptr(uint8x8x4_t,&vtmp);
+ uint8x8x4_t vrp = *vrpt;
+ uint32x2x4_t *temp_pointer;
+ uint32x2x4_t vdest_val;
+
+ vdest.val[0] = vadd_u8(vdest.val[3], vrp.val[0]);
+ vdest.val[1] = vadd_u8(vdest.val[0], vrp.val[1]);
+ vdest.val[2] = vadd_u8(vdest.val[1], vrp.val[2]);
+ vdest.val[3] = vadd_u8(vdest.val[2], vrp.val[3]);
+
+ vdest_val = png_ldr(uint32x2x4_t, &vdest);
+ vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+ }
+
+ PNG_UNUSED(prev_row)
+}
+
+void
+png_read_filter_row_avg3_neon(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp = row;
+ png_const_bytep pp = prev_row;
+ png_bytep rp_stop = row + row_info->rowbytes;
+
+ uint8x16_t vtmp;
+ uint8x8x2_t *vrpt;
+ uint8x8x2_t vrp;
+ uint8x8x4_t vdest;
+ vdest.val[3] = vdup_n_u8(0);
+
+ vtmp = vld1q_u8(rp);
+ vrpt = png_ptr(uint8x8x2_t,&vtmp);
+ vrp = *vrpt;
+
+ png_debug(1, "in png_read_filter_row_avg3_neon");
+
+ for (; rp < rp_stop; pp += 12)
+ {
+ uint8x8_t vtmp1, vtmp2, vtmp3;
+
+ uint8x8x2_t *vppt;
+ uint8x8x2_t vpp;
+
+ uint32x2_t *temp_pointer;
+
+ vtmp = vld1q_u8(pp);
+ vppt = png_ptr(uint8x8x2_t,&vtmp);
+ vpp = *vppt;
+
+ vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+ vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+ vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+ vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+ vtmp3 = vext_u8(vrp.val[0], vrp.val[1], 6);
+ vdest.val[1] = vhadd_u8(vdest.val[0], vtmp2);
+ vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+ vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 6);
+ vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+
+ vtmp = vld1q_u8(rp + 12);
+ vrpt = png_ptr(uint8x8x2_t,&vtmp);
+ vrp = *vrpt;
+
+ vdest.val[2] = vhadd_u8(vdest.val[1], vtmp2);
+ vdest.val[2] = vadd_u8(vdest.val[2], vtmp3);
+
+ vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+ vdest.val[3] = vhadd_u8(vdest.val[2], vtmp2);
+ vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+ rp += 3;
+ }
+}
+
+void
+png_read_filter_row_avg4_neon(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp = row;
+ png_bytep rp_stop = row + row_info->rowbytes;
+ png_const_bytep pp = prev_row;
+
+ uint8x8x4_t vdest;
+ vdest.val[3] = vdup_n_u8(0);
+
+ png_debug(1, "in png_read_filter_row_avg4_neon");
+
+ for (; rp < rp_stop; rp += 16, pp += 16)
+ {
+ uint32x2x4_t vtmp;
+ uint8x8x4_t *vrpt, *vppt;
+ uint8x8x4_t vrp, vpp;
+ uint32x2x4_t *temp_pointer;
+ uint32x2x4_t vdest_val;
+
+ vtmp = vld4_u32(png_ptr(uint32_t,rp));
+ vrpt = png_ptr(uint8x8x4_t,&vtmp);
+ vrp = *vrpt;
+ vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+ vppt = png_ptr(uint8x8x4_t,&vtmp);
+ vpp = *vppt;
+
+ vdest.val[0] = vhadd_u8(vdest.val[3], vpp.val[0]);
+ vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+ vdest.val[1] = vhadd_u8(vdest.val[0], vpp.val[1]);
+ vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+ vdest.val[2] = vhadd_u8(vdest.val[1], vpp.val[2]);
+ vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+ vdest.val[3] = vhadd_u8(vdest.val[2], vpp.val[3]);
+ vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+ vdest_val = png_ldr(uint32x2x4_t, &vdest);
+ vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+ }
+}
+
+static uint8x8_t
+paeth(uint8x8_t a, uint8x8_t b, uint8x8_t c)
+{
+ uint8x8_t d, e;
+ uint16x8_t p1, pa, pb, pc;
+
+ p1 = vaddl_u8(a, b); /* a + b */
+ pc = vaddl_u8(c, c); /* c * 2 */
+ pa = vabdl_u8(b, c); /* pa */
+ pb = vabdl_u8(a, c); /* pb */
+ pc = vabdq_u16(p1, pc); /* pc */
+
+ p1 = vcleq_u16(pa, pb); /* pa <= pb */
+ pa = vcleq_u16(pa, pc); /* pa <= pc */
+ pb = vcleq_u16(pb, pc); /* pb <= pc */
+
+ p1 = vandq_u16(p1, pa); /* pa <= pb && pa <= pc */
+
+ d = vmovn_u16(pb);
+ e = vmovn_u16(p1);
+
+ d = vbsl_u8(d, b, c);
+ e = vbsl_u8(e, a, d);
+
+ return e;
+}
+
+void
+png_read_filter_row_paeth3_neon(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp = row;
+ png_const_bytep pp = prev_row;
+ png_bytep rp_stop = row + row_info->rowbytes;
+
+ uint8x16_t vtmp;
+ uint8x8x2_t *vrpt;
+ uint8x8x2_t vrp;
+ uint8x8_t vlast = vdup_n_u8(0);
+ uint8x8x4_t vdest;
+ vdest.val[3] = vdup_n_u8(0);
+
+ vtmp = vld1q_u8(rp);
+ vrpt = png_ptr(uint8x8x2_t,&vtmp);
+ vrp = *vrpt;
+
+ png_debug(1, "in png_read_filter_row_paeth3_neon");
+
+ for (; rp < rp_stop; pp += 12)
+ {
+ uint8x8x2_t *vppt;
+ uint8x8x2_t vpp;
+ uint8x8_t vtmp1, vtmp2, vtmp3;
+ uint32x2_t *temp_pointer;
+
+ vtmp = vld1q_u8(pp);
+ vppt = png_ptr(uint8x8x2_t,&vtmp);
+ vpp = *vppt;
+
+ vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+ vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+
+ vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 3);
+ vtmp2 = vext_u8(vpp.val[0], vpp.val[1], 3);
+ vdest.val[1] = paeth(vdest.val[0], vtmp2, vpp.val[0]);
+ vdest.val[1] = vadd_u8(vdest.val[1], vtmp1);
+
+ vtmp1 = vext_u8(vrp.val[0], vrp.val[1], 6);
+ vtmp3 = vext_u8(vpp.val[0], vpp.val[1], 6);
+ vdest.val[2] = paeth(vdest.val[1], vtmp3, vtmp2);
+ vdest.val[2] = vadd_u8(vdest.val[2], vtmp1);
+
+ vtmp1 = vext_u8(vrp.val[1], vrp.val[1], 1);
+ vtmp2 = vext_u8(vpp.val[1], vpp.val[1], 1);
+
+ vtmp = vld1q_u8(rp + 12);
+ vrpt = png_ptr(uint8x8x2_t,&vtmp);
+ vrp = *vrpt;
+
+ vdest.val[3] = paeth(vdest.val[2], vtmp2, vtmp3);
+ vdest.val[3] = vadd_u8(vdest.val[3], vtmp1);
+
+ vlast = vtmp2;
+
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[0]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[1]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[2]), 0);
+ rp += 3;
+ vst1_lane_u32(png_ptr(uint32_t,rp), png_ldr(uint32x2_t,&vdest.val[3]), 0);
+ rp += 3;
+ }
+}
+
+void
+png_read_filter_row_paeth4_neon(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ png_bytep rp = row;
+ png_bytep rp_stop = row + row_info->rowbytes;
+ png_const_bytep pp = prev_row;
+
+ uint8x8_t vlast = vdup_n_u8(0);
+ uint8x8x4_t vdest;
+ vdest.val[3] = vdup_n_u8(0);
+
+ png_debug(1, "in png_read_filter_row_paeth4_neon");
+
+ for (; rp < rp_stop; rp += 16, pp += 16)
+ {
+ uint32x2x4_t vtmp;
+ uint8x8x4_t *vrpt, *vppt;
+ uint8x8x4_t vrp, vpp;
+ uint32x2x4_t *temp_pointer;
+ uint32x2x4_t vdest_val;
+
+ vtmp = vld4_u32(png_ptr(uint32_t,rp));
+ vrpt = png_ptr(uint8x8x4_t,&vtmp);
+ vrp = *vrpt;
+ vtmp = vld4_u32(png_ptrc(uint32_t,pp));
+ vppt = png_ptr(uint8x8x4_t,&vtmp);
+ vpp = *vppt;
+
+ vdest.val[0] = paeth(vdest.val[3], vpp.val[0], vlast);
+ vdest.val[0] = vadd_u8(vdest.val[0], vrp.val[0]);
+ vdest.val[1] = paeth(vdest.val[0], vpp.val[1], vpp.val[0]);
+ vdest.val[1] = vadd_u8(vdest.val[1], vrp.val[1]);
+ vdest.val[2] = paeth(vdest.val[1], vpp.val[2], vpp.val[1]);
+ vdest.val[2] = vadd_u8(vdest.val[2], vrp.val[2]);
+ vdest.val[3] = paeth(vdest.val[2], vpp.val[3], vpp.val[2]);
+ vdest.val[3] = vadd_u8(vdest.val[3], vrp.val[3]);
+
+ vlast = vpp.val[3];
+
+ vdest_val = png_ldr(uint32x2x4_t, &vdest);
+ vst4_lane_u32(png_ptr(uint32_t,rp), vdest_val, 0);
+ }
+}
+
+#endif /* PNG_ARM_NEON_OPT > 0 */
+#endif /* PNG_ARM_NEON_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */
diff --git a/png/arm/palette_neon_intrinsics.c b/png/arm/palette_neon_intrinsics.c
new file mode 100644
index 0000000000000000000000000000000000000000..b4d1fd2abfa292d26ae26699e8fb0ecaf377ab9a
--- /dev/null
+++ b/png/arm/palette_neon_intrinsics.c
@@ -0,0 +1,149 @@
+
+/* 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 */