Add ARM/NEON implementation for SHA-1

* cipher/Makefile.am: Add 'sha1-armv7-neon.S'.
* cipher/sha1-armv7-neon.S: New.
* cipher/sha1.c (USE_NEON): New.
(SHA1_CONTEXT, sha1_init) [USE_NEON]: Add and initialize 'use_neon'.
[USE_NEON] (_gcry_sha1_transform_armv7_neon): New.
(transform) [USE_NEON]: Use ARM/NEON assembly if enabled.
* configure.ac: Add 'sha1-armv7-neon.lo'.
--

Patch adds ARM/NEON implementation for SHA-1.

Benchmarks show 1.72x improvement on ARM Cortex-A8, 1008 Mhz:

jussi@cubie:~/libgcrypt$ tests/bench-slope --cpu-mhz 1008 hash sha1
Hash:
                |  nanosecs/byte   mebibytes/sec   cycles/byte
 SHA1           |      7.80 ns/B     122.3 MiB/s      7.86 c/B
                =
jussi@cubie:~/libgcrypt$ tests/bench-slope --disable-hwf arm-neon --cpu-mhz 1008 hash sha1
Hash:
                |  nanosecs/byte   mebibytes/sec   cycles/byte
 SHA1           |     13.41 ns/B     71.10 MiB/s     13.52 c/B
                =

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>

1 files changed, 28 insertions, 1 deletions

diff --git a/cipher/sha1.c b/cipher/sha1.c
index a55ff938..889a7ea1 100644
--- a/cipher/sha1.c
+++ b/cipher/sha1.c
@@ -64,6 +64,15 @@
 # define USE_BMI2 1
 #endif
 
+/* USE_NEON indicates whether to enable ARM NEON assembly code. */
+#undef USE_NEON
+#if defined(HAVE_ARM_ARCH_V6) && defined(__ARMEL__)
+# if defined(HAVE_COMPATIBLE_GCC_ARM_PLATFORM_AS) && \
+     defined(HAVE_GCC_INLINE_ASM_NEON)
+#  define USE_NEON 1
+# endif
+#endif
+
 
 /* A macro to test whether P is properly aligned for an u32 type.
    Note that config.h provides a suitable replacement for uintptr_t if
@@ -87,6 +96,9 @@ typedef struct
 #ifdef USE_BMI2
   unsigned int use_bmi2:1;
 #endif
+#ifdef USE_NEON
+  unsigned int use_neon:1;
+#endif
 } SHA1_CONTEXT;
 
 static unsigned int
@@ -122,6 +134,9 @@ sha1_init (void *context)
 #ifdef USE_BMI2
   hd->use_bmi2 = (features & HWF_INTEL_AVX) && (features & HWF_INTEL_BMI2);
 #endif
+#ifdef USE_NEON
+  hd->use_neon = (features & HWF_ARM_NEON) != 0;
+#endif
   (void)features;
 }
 
@@ -148,6 +163,13 @@ sha1_init (void *context)
 			       } while(0)
 
 
+
+#ifdef USE_NEON
+unsigned int
+_gcry_sha1_transform_armv7_neon (void *state, const unsigned char *data,
+                                 size_t nblks);
+#endif
+
 /*
  * Transform NBLOCKS of each 64 bytes (16 32-bit words) at DATA.
  */
@@ -302,10 +324,15 @@ transform (void *ctx, const unsigned char *data, size_t nblks)
     return _gcry_sha1_transform_amd64_ssse3 (&hd->h0, data, nblks)
            + 4 * sizeof(void*);
 #endif
+#ifdef USE_NEON
+  if (hd->use_neon)
+    return _gcry_sha1_transform_armv7_neon (&hd->h0, data, nblks)
+           + 4 * sizeof(void*);
+#endif
 
   do
     {
-      burn = transform_blk (ctx, data);
+      burn = transform_blk (hd, data);
       data += 64;
     }
   while (--nblks);