Fix ChaCha NEON compile with MSVC compiler (GH #776)

1 files changed, 12 insertions, 1 deletions

diff --git a/chacha_simd.cpp b/chacha_simd.cpp
index 534445a6..b7d9c0a9 100644
--- a/chacha_simd.cpp
+++ b/chacha_simd.cpp
@@ -70,6 +70,15 @@ ANONYMOUS_NAMESPACE_BEGIN
 

 // ***************************** NEON ***************************** //

 

+// Thanks to Peter Cordes, https://stackoverflow.com/q/54016821/608639

+#if (CRYPTOPP_ARM_NEON_AVAILABLE)

+# if defined(_MSC_VER)

+#  define PACK32x4(w,x,y,z) { ((w) + (word64(x) << 32)), ((y) + (word64(z) << 32)) }

+# else

+#  define PACK32x4(w,x,y,z) { (w), (x), (y), (z) }

+# endif

+#endif  // Microsoft workaround

+

 #if (CRYPTOPP_ARM_NEON_AVAILABLE)

 

 template <unsigned int R>

@@ -303,7 +312,9 @@ void ChaCha_OperateKeystream_NEON(const word32 *state, const byte* input, byte *
     const uint32x4_t state3 = vld1q_u32(state + 3*4);

 

     const uint32x4_t CTRS[3] = {

-        {1,0,0,0}, {2,0,0,0}, {3,0,0,0}

+        PACK32x4(1,0,0,0),

+        PACK32x4(2,0,0,0),

+        PACK32x4(3,0,0,0)

     };

 

     uint32x4_t r0_0 = state0;