[RFC PATCH v1 1/3] lib/simd: Introduce vectorization framework for libvorbis

Many CPUs have vectorization support that can greatly
increase the performance of certain signal processing functions.

Introduces generic vectorization framework into libvorbis
and some ARM NEON implementations.

Signed-off-by: Viswanath Puttagunta <[email protected]>
---
 configure.ac         |    5 +++++
 lib/Makefile.am      |    6 +++---
 lib/simd/Makefile.am |    9 +++++++++
 lib/simd/neon_simd.c |   47 +++++++++++++++++++++++++++++++++++++++++++++++
 lib/simd/no_simd.c   |   28 ++++++++++++++++++++++++++++
 lib/simd/simd.h      |   29 +++++++++++++++++++++++++++++
 6 files changed, 121 insertions(+), 3 deletions(-)
 create mode 100644 lib/simd/Makefile.am
 create mode 100644 lib/simd/neon_simd.c
 create mode 100644 lib/simd/no_simd.c
 create mode 100644 lib/simd/simd.h

diff --git a/configure.ac b/configure.ac
index ee2db99..28b4aaa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -93,6 +93,10 @@ AC_ARG_ENABLE(examples,
  	
 AM_CONDITIONAL(BUILD_EXAMPLES, [test "x$enable_examples" = xyes]) 
 
+AC_ARG_ENABLE([arm-neon],
+  [enables arm_neon],[arm_neon=${enableval}],[arm_neon=no])
+AM_CONDITIONAL([ARM_NEON], [test x$arm_neon = xyes])
+
 dnl --------------------------------------------------
 dnl Set build flags based on environment
 dnl --------------------------------------------------
@@ -275,6 +279,7 @@ AC_CONFIG_FILES([
 Makefile
 m4/Makefile
 lib/Makefile
+lib/simd/Makefile
 lib/modes/Makefile
 lib/books/Makefile
 lib/books/coupled/Makefile
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 50f7ea4..0727398 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,8 +1,8 @@
 ## Process this file with automake to produce Makefile.in
 
-SUBDIRS = modes books
+SUBDIRS = simd modes books
 
-INCLUDES = -I$(top_srcdir)/include @OGG_CFLAGS@
+INCLUDES = -I$(top_srcdir)/include @OGG_CFLAGS@ -I$(top_srcdir)/lib/simd
 
 lib_LTLIBRARIES = libvorbis.la libvorbisfile.la libvorbisenc.la
 
@@ -16,7 +16,7 @@ libvorbis_la_SOURCES = mdct.c smallft.c block.c envelope.c window.c lsp.c \
 			registry.h scales.h window.h lookup.h lookup_data.h\
 			codec_internal.h backends.h bitrate.h 
 libvorbis_la_LDFLAGS = -no-undefined -version-info @V_LIB_CURRENT@:@V_LIB_REVISION@:@V_LIB_AGE@
-libvorbis_la_LIBADD = @VORBIS_LIBS@ @OGG_LIBS@
+libvorbis_la_LIBADD = @VORBIS_LIBS@ @OGG_LIBS@ ./simd/libsimd.la
 
 libvorbisfile_la_SOURCES = vorbisfile.c
 libvorbisfile_la_LDFLAGS = -no-undefined -version-info @VF_LIB_CURRENT@:@VF_LIB_REVISION@:@VF_LIB_AGE@
diff --git a/lib/simd/Makefile.am b/lib/simd/Makefile.am
new file mode 100644
index 0000000..7225431
--- /dev/null
+++ b/lib/simd/Makefile.am
@@ -0,0 +1,9 @@
+INCLUDES = -I$(top_srcdir)/include -I$(top_srcdir)/lib @OGG_CFLAGS@
+noinst_LTLIBRARIES = libsimd.la
+
+if ARM_NEON
+libsimd_la_CPPFLAGS = -mfpu=neon-vfpv4 -O3
+libsimd_la_SOURCES = simd.h neon_simd.c
+else
+libsimd_la_SOURCES = simd.h no_simd.c
+endif
diff --git a/lib/simd/neon_simd.c b/lib/simd/neon_simd.c
new file mode 100644
index 0000000..381d704
--- /dev/null
+++ b/lib/simd/neon_simd.c
@@ -0,0 +1,47 @@
+/********************************************************************
+ *                                                                  *
+ * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
+ * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
+ * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
+ * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
+ *                                                                  *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
+ * by the Xiph.Org Foundation http://www.xiph.org/                  *
+ *                                                                  *
+ ********************************************************************/
+
+/* Optimized functions using ARM NEON */
+
+#include <stdint.h>
+#include <arm_neon.h>
+#include "simd.h"
+
+/* wave_operation: Implements pseudo-code
+ * for(i = 0; i < n; i++)
+ *      a[i] = a[i]*b[n-i-1] + a[i]*c[i]
+ * Assumes n is multiple of 4
+ */
+void wave_operation(float *a, float *b, float *c, int32_t n) {
+        float32x4_t result, tmpa, tmpb, tmpc, tmpd;
+        float *ai, *bi, *ci, *di;
+        float32x2_t vec64l, vec64h;
+
+        for (ai = a, bi = b+n-4, ci=c, di=b; \
+                ai < (a+n); ai += 4, bi-=4, ci+=4, di+=4) {
+                tmpa = vld1q_f32(ai);
+                tmpb = vld1q_f32(bi);
+		__builtin_prefetch(ai);
+                vec64l = vget_low_f32(tmpb);
+                vec64h = vget_high_f32(tmpb);
+                tmpb = vcombine_f32(vec64h, vec64l);
+                tmpb = vrev64q_f32(tmpb);
+                tmpc = vld1q_f32(ci);
+                tmpd = vld1q_f32(di);
+		__builtin_prefetch(ci);
+
+                result = vmulq_f32(tmpa, tmpb);
+                result = vmlaq_f32(result, tmpc, tmpd);
+
+                vst1q_f32(ai, result);
+        }
+}
diff --git a/lib/simd/no_simd.c b/lib/simd/no_simd.c
new file mode 100644
index 0000000..e8efacb
--- /dev/null
+++ b/lib/simd/no_simd.c
@@ -0,0 +1,28 @@
+/********************************************************************
+ *                                                                  *
+ * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
+ * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
+ * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
+ * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
+ *                                                                  *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
+ * by the Xiph.Org Foundation http://www.xiph.org/                  *
+ *                                                                  *
+ ********************************************************************/
+
+/* Implementation when CPU Vectorization is not available */
+
+#include <stdint.h>
+#include "simd.h"
+#include "os.h"
+
+/* wave_operation: Implements pseudo-code
+ * for(i = 0; i < n; i++)
+ *      a[i] = a[i]*b[n-i-1] + a[i]*c[i]
+ */
+void wave_operation(float *a, float *b, float *c, int32_t n) {
+        int32_t i;
+
+        for (i = 0; i < n; i++)
+                a[i] = a[i]*b[n-i-1] + b[i]*c[i];
+}
diff --git a/lib/simd/simd.h b/lib/simd/simd.h
new file mode 100644
index 0000000..8565434
--- /dev/null
+++ b/lib/simd/simd.h
@@ -0,0 +1,29 @@
+/********************************************************************
+ *                                                                  *
+ * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
+ * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
+ * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
+ * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
+ *                                                                  *
+ * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
+ * by the Xiph.Org Foundation http://www.xiph.org/                  *
+ *                                                                  *
+ ********************************************************************
+
+ function: Declarations for functions that can be optimized with
+	   CPU vectorization if available
+ ********************************************************************/
+
+#ifndef SIMD_H
+#define SIMD_H
+
+#include "os.h"
+
+/* wave_operation: Must implement pseudo-code
+ * for(i = 0; i < n; i++)
+ *      a[i] = a[i]*b[n-i-1] + b[i]*c[i]
+ * n must be multiple of 4
+ */
+void wave_operation(float *a, float *b, float *c, int32_t n);
+
+#endif
-- 
1.7.9.5