From a4ebb75538f1fde6cdba481765b5f9216ecb0bc3 Mon Sep 17 00:00:00 2001
From: Jeffrey Walton <noloader@gmail.com>
Date: Mon, 6 Aug 2018 18:37:25 -0400
Subject: [PATCH] Update comments

---
 gcm-simd.cpp | 12 ++++++++----
 ppc-simd.h   | 14 ++++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/gcm-simd.cpp b/gcm-simd.cpp
index 123fefde..8e3ca50a 100644
--- a/gcm-simd.cpp
+++ b/gcm-simd.cpp
@@ -168,9 +168,10 @@ using CryptoPP::uint64x2_p;
 using CryptoPP::VectorAnd;
 using CryptoPP::VectorShiftRight;
 
+// _mm_clmulepi64_si128(a, b, 0x00)
+// High dwords of 'a' and 'b' are masked out.
 inline uint64x2_p VMULL_00(uint64x2_p a, uint64x2_p b)
 {
-	// Multiplies low dwords
 #if defined(__xlc__) || defined(__xlC__)
 	const uint64x2_p m = {0xffffffffffffffffull, 0};
 	return __vpmsumd (VectorAnd(a, m), VectorAnd(b, m));
@@ -180,9 +181,10 @@ inline uint64x2_p VMULL_00(uint64x2_p a, uint64x2_p b)
 #endif
 }
 
+// _mm_clmulepi64_si128(a, b, 0x01)
+// High dword of 'a' is masked out. High dword of 'b' is shifted down.
 inline uint64x2_p VMULL_01(uint64x2_p a, uint64x2_p b)
 {
-	// Multiplies high and low dwords
 #if defined(__xlc__) || defined(__xlC__)
 	const uint64x2_p m = {0xffffffffffffffffull, 0};
 	return __vpmsumd (VectorAnd(a, m), VectorShiftRight<8>(b));
@@ -192,9 +194,10 @@ inline uint64x2_p VMULL_01(uint64x2_p a, uint64x2_p b)
 #endif
 }
 
+// _mm_clmulepi64_si128(a, b, 0x10)
+// High dword of 'a' is shifted down. High dword of 'b' is masked out.
 inline uint64x2_p VMULL_10(uint64x2_p a, uint64x2_p b)
 {
-	// Multiplies high and low dwords
 #if defined(__xlc__) || defined(__xlC__)
 	const uint64x2_p m = {0xffffffffffffffffull, 0};
 	return __vpmsumd (VectorShiftRight<8>(a), VectorAnd(b, m));
@@ -204,9 +207,10 @@ inline uint64x2_p VMULL_10(uint64x2_p a, uint64x2_p b)
 #endif
 }
 
+// _mm_clmulepi64_si128(a, b, 0x11)
+// Low dwords of 'a' and 'b' are masked out.
 inline uint64x2_p VMULL_11(uint64x2_p a, uint64x2_p b)
 {
-	// Multiplies high dwords
 #if defined(__xlc__) || defined(__xlC__)
 	const uint64x2_p m = {0, 0xffffffffffffffffull};
 	return __vpmsumd (VectorAnd(a, m), VectorAnd(b, m));
diff --git a/ppc-simd.h b/ppc-simd.h
index e076cc94..f3cdc7d3 100644
--- a/ppc-simd.h
+++ b/ppc-simd.h
@@ -90,6 +90,20 @@ inline T1 VectorPermute(const T1& vec1, const T1& vec2, const T2& mask)
     return (T1)vec_perm(vec1, vec2, (uint8x16_p)mask);
 }
 
+/// \brief AND two vectors
+/// \tparam T1 vector type
+/// \tparam T2 vector type
+/// \param vec1 the first vector
+/// \param vec2 the second vector
+/// \details VectorAnd returns a new vector from vec1 and vec2. The return
+///   vector is the same type as vec1.
+/// \since Crypto++ 6.0
+template <class T1, class T2>
+inline T1 VectorAnd(const T1& vec1, const T2& vec2)
+{
+    return (T1)vec_and(vec1, (T1)vec2);
+}
+
 /// \brief XOR two vectors
 /// \tparam T1 vector type
 /// \tparam T2 vector type