Use pshufhw + pshuflw for 16-bit rotate.

ChangeLog

 2014-01-27  Niels Möller  <nisse@lysator.liu.se>
 
+	* x86_64/chacha-core-internal.asm: Use pshufhw + pshuflw for the
+	16-bit rotate.
+
 	* configure.ac (asm_replace_list): Added chacha-core-internal.asm.
 	* x86_64/chacha-core-internal.asm: New file.
 

x86_64/chacha-core-internal.asm

@@ -27,14 +27,26 @@ define(<X3>, <%xmm3>)
 define(<T0>, <%xmm4>)
 define(<T1>, <%xmm5>)
 
+define(<USE_PSHUFW>, <yes>)
+
+C ROTL_BY_16(REG, TMP)
+ifelse(USE_PSHUFW, <yes>, <
+define(<ROTL_BY_16>, <
+	pshufhw	<$>0xb1, $1, $1
+	pshuflw	<$>0xb1, $1, $1
+>)>, <
+define(<ROTL_BY_16>, <
+	pslld	<$>16, $1
+	psrld	<$>16, $2
+	por	$2, $1
+>)
+>)
 C QROUND
 define(<QROUND>, <
 	paddd	X1, X0
 	pxor	X0, X3
 	movaps	X3, T0
-	pslld	<$>16, X3
-	psrld	<$>16, T0
-	por	T0, X3
+	ROTL_BY_16(X3, T0)
 
 	paddd	X3, X2
 	pxor	X2, X1