Pre-splat SIMON and SPECK keys when appropriate for Altivec (PR #910)

SIMON and SPECK keys can be pre-splatted in the forward direction when Altivec instructions will be used. Pre-splatting does not work for the reverse transformation. It breaks modes like CBC, so the speed-up is only applied to the forward transformation.

1 files changed, 19 insertions, 3 deletions

diff --git a/simon.cpp b/simon.cpp
index a35762de..e27bf1be 100644
--- a/simon.cpp
+++ b/simon.cpp
@@ -326,10 +326,15 @@ void SIMON64::Base::UncheckedSetKey(const byte *userKey, unsigned int keyLength,
         CRYPTOPP_ASSERT(0);

     }

 

-    // Altivec loads the current subkey as a 16-byte vector

-    // The extra elements ensure memory backs the last subkey.

+    // Pre-splat the round keys for Altivec forward transformation

 #if CRYPTOPP_ALTIVEC_AVAILABLE

-    m_rkeys.Grow(m_rkeys.size()+4);

+    if (IsForwardTransformation() && HasAltivec())

+    {

+        AlignedSecBlock presplat(m_rkeys.size()*4);

+        for (size_t i=0, j=0; i<m_rkeys.size(); i++, j+=4)

+            presplat[j+0] = presplat[j+1] = presplat[j+2] = presplat[j+3] = m_rkeys[i];

+        m_rkeys.swap(presplat);

+    }

 #endif

 }

 

@@ -453,6 +458,17 @@ void SIMON128::Base::UncheckedSetKey(const byte *userKey, unsigned int keyLength
     default:

         CRYPTOPP_ASSERT(0);

     }

+

+    // Pre-splat the round keys for Power8 forward transformation

+#if CRYPTOPP_POWER8_AVAILABLE

+    if (IsForwardTransformation() && HasPower8())

+    {

+        AlignedSecBlock presplat(m_rkeys.size()*2);

+        for (size_t i=0, j=0; i<m_rkeys.size(); i++, j+=2)

+            presplat[j+0] = presplat[j+1] = m_rkeys[i];

+        m_rkeys.swap(presplat);

+    }

+#endif

 }

 

 void SIMON128::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const