crypto/md5: fix md5block asm to work on big endian ppc64

This handles a TODO in the md5block_ppc64le.s file to
make use of byte reverse loads so the function works for
big endian as well as little endian. File name is now
md5block_ppc64x.s.

name                 old time/op    new time/op    delta
Hash8Bytes              537ns ± 0%     299ns ± 0%  -44.32%  (p=0.000 n=8+1)
Hash1K                 4.74µs ± 0%    3.24µs ± 0%  -31.64%  (p=0.250 n=7+1)
Hash8K                 34.4µs ± 0%    23.6µs ± 0%  -31.56%  (p=0.222 n=8+1)
Hash8BytesUnaligned     537ns ± 0%     298ns ± 0%  -44.51%  (p=0.000 n=8+1)
Hash1KUnaligned        4.74µs ± 0%    3.24µs ± 0%  -31.48%  (p=0.222 n=8+1)
Hash8KUnaligned        34.4µs ± 0%    23.6µs ± 0%  -31.39%  (p=0.222 n=8+1)

name                 old speed      new speed      delta
Hash8Bytes           14.9MB/s ± 0%  26.8MB/s ± 0%  +79.76%  (p=0.222 n=8+1)
Hash1K                216MB/s ± 0%   316MB/s ± 0%  +46.29%  (p=0.250 n=7+1)
Hash8K                238MB/s ± 0%   348MB/s ± 0%  +46.11%  (p=0.222 n=8+1)
Hash8BytesUnaligned  14.9MB/s ± 0%  26.8MB/s ± 0%  +79.76%  (p=0.222 n=8+1)
Hash1KUnaligned       216MB/s ± 0%   316MB/s ± 0%  +45.95%  (p=0.222 n=8+1)
Hash8KUnaligned       238MB/s ± 0%   347MB/s ± 0%  +45.75%  (p=0.222 n=8+1)

Change-Id: I2e226bf7e69e0acd49db1af42e4fd8b87b155606
Reviewed-on: https://go-review.googlesource.com/c/144599
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Michael Munday <mike.munday@ibm.com>

src/crypto/md5/md5block_decl.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build amd64 amd64p32 386 arm ppc64le s390x arm64
+// +build amd64 amd64p32 386 arm ppc64le ppc64 s390x arm64
 
 package md5
 

src/crypto/md5/md5block_generic.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64,!amd64p32,!386,!arm,!ppc64le,!s390x,!arm64
+// +build !amd64,!amd64p32,!386,!arm,!ppc64le,!ppc64,!s390x,!arm64
 
 package md5
 

src/crypto/md5/md5block_ppc64le.s → src/crypto/md5/md5block_ppc64x.s

@@ -10,14 +10,23 @@
 // Licence: I hereby disclaim the copyright on this code and place it
 // in the public domain.
 
-#include "textflag.h"
+// +build ppc64 ppc64le
 
-// TODO: Could be updated for ppc64 big endian
-// by using the correct byte reverse instruction.
-// Changes required in the Go assembler to make
-// that instruction work.
+#include "textflag.h"
 
-#define MOVE_LITTLE_ENDIAN MOVWZ
+// ENDIAN_MOVE generates the appropriate
+// 4 byte load for big or little endian.
+// The 4 bytes at ptr+off is loaded into dst.
+// The idx reg is only needed for big endian
+// and is clobbered when used.
+#ifdef GOARCH_ppc64le
+#define ENDIAN_MOVE(off, ptr, dst, idx) \
+	MOVWZ	off(ptr),dst
+#else
+#define ENDIAN_MOVE(off, ptr, dst, idx) \
+	MOVD	$off,idx; \
+	MOVWBR	(idx)(ptr), dst
+#endif
 
 TEXT ·block(SB),NOSPLIT,$0-32
 	MOVD	dig+0(FP), R10
@@ -40,7 +49,7 @@ loop:
 	MOVWZ	R4, R16
 	MOVWZ	R5, R17
 
-	MOVE_LITTLE_ENDIAN	0(R6), R8
+	ENDIAN_MOVE(0,R6,R8,R21)
 	MOVWZ	R5, R9
 
 #define ROUND1(a, b, c, d, index, const, shift) \
@@ -49,7 +58,7 @@ loop:
 	ADD	R8, a; \
 	AND	b, R9; \
 	XOR	d, R9; \
-	MOVE_LITTLE_ENDIAN	(index*4)(R6), R8; \
+	ENDIAN_MOVE(index*4,R6,R8,R21); \
 	ADD	R9, a; \
 	RLWMI	$shift, a, $0xffffffff, a; \
 	MOVWZ	c, R9; \
@@ -73,7 +82,7 @@ loop:
 	ROUND1(R4,R5,R22,R3,15,0xa679438e,17);
 	ROUND1(R3,R4,R5,R22, 0,0x49b40821,22);
 
-	MOVE_LITTLE_ENDIAN	(1*4)(R6), R8
+	ENDIAN_MOVE(1*4,R6,R8,R21)
 	MOVWZ	R5, R9
 	MOVWZ	R5, R10
 
@@ -83,7 +92,7 @@ loop:
 	ADD	R8, a; \
 	AND	b, R10; \
 	AND	c, R9; \
-	MOVE_LITTLE_ENDIAN	(index*4)(R6), R8; \
+	ENDIAN_MOVE(index*4,R6,R8,R21); \
 	OR	R9, R10; \
 	MOVWZ	c, R9; \
 	ADD	R10, a; \
@@ -109,13 +118,13 @@ loop:
 	ROUND2(R4,R5,R22,R3,12,0x676f02d9,14);
 	ROUND2(R3,R4,R5,R22, 0,0x8d2a4c8a,20);
 
-	MOVE_LITTLE_ENDIAN	(5*4)(R6), R8
+	ENDIAN_MOVE(5*4,R6,R8,R21)
 	MOVWZ	R4, R9
 
 #define ROUND3(a, b, c, d, index, const, shift) \
 	ADD	$const, a; \
 	ADD	R8, a; \
-	MOVE_LITTLE_ENDIAN	(index*4)(R6), R8; \
+	ENDIAN_MOVE(index*4,R6,R8,R21); \
 	XOR	d, R9; \
 	XOR	b, R9; \
 	ADD	R9, a; \
@@ -141,7 +150,7 @@ loop:
 	ROUND3(R4,R5,R22,R3, 2,0x1fa27cf8,16);
 	ROUND3(R3,R4,R5,R22, 0,0xc4ac5665,23);
 
-	MOVE_LITTLE_ENDIAN	(0*4)(R6), R8
+	ENDIAN_MOVE(0,R6,R8,R21)
 	MOVWZ	$0xffffffff, R9
 	XOR	R5, R9
 
@@ -151,7 +160,7 @@ loop:
 	OR	b, R9; \
 	XOR	c, R9; \
 	ADD	R9, a; \
-	MOVE_LITTLE_ENDIAN	(index*4)(R6), R8; \
+	ENDIAN_MOVE(index*4,R6,R8,R21); \
 	MOVWZ	$0xffffffff, R9; \
 	RLWMI	$shift, a, $0xffffffff, a; \
 	XOR	c, R9; \