Added initial code for PowerPC VSX optimisation

1 files changed, 233 insertions, 0 deletions

diff --git a/powerpc/filter_vsx_intrinsics.c b/powerpc/filter_vsx_intrinsics.c
new file mode 100644
index 000000000..8e4ef2930
--- /dev/null
+++ b/powerpc/filter_vsx_intrinsics.c
@@ -0,0 +1,233 @@
+
+/* filter_vsx_intrinsics.c - PowerPC optimised filter functions
+ *
+ * Copyright (c) 2016 Glenn Randers-Pehrson
+ * Written by Vadim Barkov, 2017.
+ * Last changed in libpng 1.6.25 [September 1, 2016]
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+#include <stdio.h>
+#include <stdint.h>
+#include "../pngpriv.h"
+
+#ifdef PNG_READ_SUPPORTED
+
+/* This code requires -maltivec and -mabi=altivec on the command line: */
+#if PNG_POWERPC_VSX_IMPLEMENTATION == 1 /* intrinsics code from pngpriv.h */
+
+/* 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)
+
+/*#include <altivec.h>*/
+
+#if PNG_POWERPC_VSX_OPT > 0
+
+void png_read_filter_row_up_vsx(png_row_infop row_info, png_bytep row,
+                                png_const_bytep prev_row)
+{
+   png_size_t i;
+   png_size_t istop = row_info->rowbytes;
+   png_bytep rp = row;
+   png_const_bytep pp = prev_row;
+
+   for (i = 0; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+      rp++;
+   }
+
+}
+
+void png_read_filter_row_sub4_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+   png_size_t i;
+   png_size_t istop = row_info->rowbytes;
+   unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+   png_bytep rp = row + bpp;
+
+   PNG_UNUSED(prev_row)
+
+   for (i = bpp; i < istop; i++)
+   {
+      *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+      rp++;
+   }
+}
+
+void png_read_filter_row_sub3_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+    png_size_t i;
+    png_size_t istop = row_info->rowbytes;
+    unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+    png_bytep rp = row + bpp;
+
+    PNG_UNUSED(prev_row)
+
+    for (i = bpp; i < istop; i++)
+    {
+       *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
+       rp++;
+    }
+}
+
+void png_read_filter_row_avg4_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+    png_size_t i;
+    png_bytep rp = row;
+    png_const_bytep pp = prev_row;
+    unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+    png_size_t istop = row_info->rowbytes - bpp;
+
+    for (i = 0; i < bpp; i++)
+    {
+       *rp = (png_byte)(((int)(*rp) +
+          ((int)(*pp++) / 2 )) & 0xff);
+
+       rp++;
+    }
+
+    for (i = 0; i < istop; i++)
+    {
+       *rp = (png_byte)(((int)(*rp) +
+          (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+       rp++;
+    }
+}
+
+void png_read_filter_row_avg3_vsx(png_row_infop row_info, png_bytep row,
+                                  png_const_bytep prev_row)
+{
+    png_size_t i;
+    png_bytep rp = row;
+    png_const_bytep pp = prev_row;
+    unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+    png_size_t istop = row_info->rowbytes - bpp;
+
+    for (i = 0; i < bpp; i++)
+    {
+       *rp = (png_byte)(((int)(*rp) +
+          ((int)(*pp++) / 2 )) & 0xff);
+
+       rp++;
+    }
+
+    for (i = 0; i < istop; i++)
+    {
+       *rp = (png_byte)(((int)(*rp) +
+          (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
+
+       rp++;
+    }
+}
+
+void png_read_filter_row_paeth4_vsx(png_row_infop row_info,
+                                    png_bytep row,
+                                    png_const_bytep prev_row)
+{
+    unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+    png_bytep rp_end = row + bpp;
+
+    /* Process the first pixel in the row completely (this is the same as 'up'
+     * because there is only one candidate predictor for the first row).
+     */
+    while (row < rp_end)
+    {
+       int a = *row + *prev_row++;
+       *row++ = (png_byte)a;
+    }
+
+    /* Remainder */
+    rp_end = rp_end + (row_info->rowbytes - bpp);
+
+    while (row < rp_end)
+    {
+       int a, b, c, pa, pb, pc, p;
+
+       c = *(prev_row - bpp);
+       a = *(row - bpp);
+       b = *prev_row++;
+
+       p = b - c;
+       pc = a - c;
+
+ #ifdef PNG_USE_ABS
+       pa = abs(p);
+       pb = abs(pc);
+       pc = abs(p + pc);
+ #else
+       pa = p < 0 ? -p : p;
+       pb = pc < 0 ? -pc : pc;
+       pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+ #endif
+
+       if (pb < pa) pa = pb, a = b;
+       if (pc < pa) a = c;
+
+       a += *row;
+       *row++ = (png_byte)a;
+    }
+}
+
+void png_read_filter_row_paeth3_vsx(png_row_infop row_info,
+                                    png_bytep row,
+                                    png_const_bytep prev_row)
+{
+    unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
+    png_bytep rp_end = row + bpp;
+
+    /* Process the first pixel in the row completely (this is the same as 'up'
+     * because there is only one candidate predictor for the first row).
+     */
+    while (row < rp_end)
+    {
+       int a = *row + *prev_row++;
+       *row++ = (png_byte)a;
+    }
+
+    /* Remainder */
+    rp_end = rp_end + (row_info->rowbytes - bpp);
+
+    while (row < rp_end)
+    {
+       int a, b, c, pa, pb, pc, p;
+
+       c = *(prev_row - bpp);
+       a = *(row - bpp);
+       b = *prev_row++;
+
+       p = b - c;
+       pc = a - c;
+
+ #ifdef PNG_USE_ABS
+       pa = abs(p);
+       pb = abs(pc);
+       pc = abs(p + pc);
+ #else
+       pa = p < 0 ? -p : p;
+       pb = pc < 0 ? -pc : pc;
+       pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+ #endif
+
+       if (pb < pa) pa = pb, a = b;
+       if (pc < pa) a = c;
+
+       a += *row;
+       *row++ = (png_byte)a;
+    }
+}
+
+#endif /* PNG_POWERPC_VSX_OPT > 0 */
+#endif /* PNG_POWERPC_VSX_IMPLEMENTATION == 1 (intrinsics) */
+#endif /* READ */