block-sha1: perform register rotation using cpp

Instead of letting the compiler to figure out the optimal way to rotate
register usage, explicitly rotate the register names with cpp.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 90 insertions, 27 deletions

diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c
index fdd400f22d..b715916675 100644
--- a/block-sha1/sha1.c
+++ b/block-sha1/sha1.c
@@ -101,20 +101,20 @@ void blk_SHA1_Final(unsigned char hashout[20], blk_SHA_CTX *ctx)
 #define SHA_SRC(t) htonl(data[t])
 #define SHA_MIX(t) SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
 
-#define SHA_ROUND(t, input, fn, constant) \
-	TEMP = input(t); W(t) = TEMP; \
-	TEMP += SHA_ROL(A,5) + (fn) + E + (constant); \
-	E = D; D = C; C = SHA_ROR(B, 2); B = A; A = TEMP
+#define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
+	unsigned int TEMP = input(t); W(t) = TEMP; \
+	TEMP += E + SHA_ROL(A,5) + (fn) + (constant); \
+	B = SHA_ROR(B, 2); E = TEMP; } while (0)
 
-#define T_0_15(t)  SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999 )
-#define T_16_19(t) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999 )
-#define T_20_39(t) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1 )
-#define T_40_59(t) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc )
-#define T_60_79(t) SHA_ROUND(t, SHA_MIX, (B^C^D) ,  0xca62c1d6 )
+#define T_0_15(t, A, B, C, D, E)  SHA_ROUND(t, SHA_SRC, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
+#define T_16_19(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (((C^D)&B)^D) , 0x5a827999, A, B, C, D, E )
+#define T_20_39(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) , 0x6ed9eba1, A, B, C, D, E )
+#define T_40_59(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, ((B&C)+(D&(B^C))) , 0x8f1bbcdc, A, B, C, D, E )
+#define T_60_79(t, A, B, C, D, E) SHA_ROUND(t, SHA_MIX, (B^C^D) ,  0xca62c1d6, A, B, C, D, E )
 
 static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)
 {
-	unsigned int A,B,C,D,E,TEMP;
+	unsigned int A,B,C,D,E;
 	unsigned int array[16];
 
 	A = ctx->H[0];
@@ -124,31 +124,94 @@ static void blk_SHA1Block(blk_SHA_CTX *ctx, const unsigned int *data)
 	E = ctx->H[4];
 
 	/* Round 1 - iterations 0-16 take their input from 'data' */
-	T_0_15( 0); T_0_15( 1); T_0_15( 2); T_0_15( 3); T_0_15( 4);
-	T_0_15( 5); T_0_15( 6); T_0_15( 7); T_0_15( 8); T_0_15( 9);
-	T_0_15(10); T_0_15(11); T_0_15(12); T_0_15(13); T_0_15(14);
-	T_0_15(15);
+	T_0_15( 0, A, B, C, D, E);
+	T_0_15( 1, E, A, B, C, D);
+	T_0_15( 2, D, E, A, B, C);
+	T_0_15( 3, C, D, E, A, B);
+	T_0_15( 4, B, C, D, E, A);
+	T_0_15( 5, A, B, C, D, E);
+	T_0_15( 6, E, A, B, C, D);
+	T_0_15( 7, D, E, A, B, C);
+	T_0_15( 8, C, D, E, A, B);
+	T_0_15( 9, B, C, D, E, A);
+	T_0_15(10, A, B, C, D, E);
+	T_0_15(11, E, A, B, C, D);
+	T_0_15(12, D, E, A, B, C);
+	T_0_15(13, C, D, E, A, B);
+	T_0_15(14, B, C, D, E, A);
+	T_0_15(15, A, B, C, D, E);
 
 	/* Round 1 - tail. Input from 512-bit mixing array */
-	T_16_19(16); T_16_19(17); T_16_19(18); T_16_19(19);
+	T_16_19(16, E, A, B, C, D);
+	T_16_19(17, D, E, A, B, C);
+	T_16_19(18, C, D, E, A, B);
+	T_16_19(19, B, C, D, E, A);
 
 	/* Round 2 */
-	T_20_39(20); T_20_39(21); T_20_39(22); T_20_39(23); T_20_39(24);
-	T_20_39(25); T_20_39(26); T_20_39(27); T_20_39(28); T_20_39(29);
-	T_20_39(30); T_20_39(31); T_20_39(32); T_20_39(33); T_20_39(34);
-	T_20_39(35); T_20_39(36); T_20_39(37); T_20_39(38); T_20_39(39);
+	T_20_39(20, A, B, C, D, E);
+	T_20_39(21, E, A, B, C, D);
+	T_20_39(22, D, E, A, B, C);
+	T_20_39(23, C, D, E, A, B);
+	T_20_39(24, B, C, D, E, A);
+	T_20_39(25, A, B, C, D, E);
+	T_20_39(26, E, A, B, C, D);
+	T_20_39(27, D, E, A, B, C);
+	T_20_39(28, C, D, E, A, B);
+	T_20_39(29, B, C, D, E, A);
+	T_20_39(30, A, B, C, D, E);
+	T_20_39(31, E, A, B, C, D);
+	T_20_39(32, D, E, A, B, C);
+	T_20_39(33, C, D, E, A, B);
+	T_20_39(34, B, C, D, E, A);
+	T_20_39(35, A, B, C, D, E);
+	T_20_39(36, E, A, B, C, D);
+	T_20_39(37, D, E, A, B, C);
+	T_20_39(38, C, D, E, A, B);
+	T_20_39(39, B, C, D, E, A);
 
 	/* Round 3 */
-	T_40_59(40); T_40_59(41); T_40_59(42); T_40_59(43); T_40_59(44);
-	T_40_59(45); T_40_59(46); T_40_59(47); T_40_59(48); T_40_59(49);
-	T_40_59(50); T_40_59(51); T_40_59(52); T_40_59(53); T_40_59(54);
-	T_40_59(55); T_40_59(56); T_40_59(57); T_40_59(58); T_40_59(59);
+	T_40_59(40, A, B, C, D, E);
+	T_40_59(41, E, A, B, C, D);
+	T_40_59(42, D, E, A, B, C);
+	T_40_59(43, C, D, E, A, B);
+	T_40_59(44, B, C, D, E, A);
+	T_40_59(45, A, B, C, D, E);
+	T_40_59(46, E, A, B, C, D);
+	T_40_59(47, D, E, A, B, C);
+	T_40_59(48, C, D, E, A, B);
+	T_40_59(49, B, C, D, E, A);
+	T_40_59(50, A, B, C, D, E);
+	T_40_59(51, E, A, B, C, D);
+	T_40_59(52, D, E, A, B, C);
+	T_40_59(53, C, D, E, A, B);
+	T_40_59(54, B, C, D, E, A);
+	T_40_59(55, A, B, C, D, E);
+	T_40_59(56, E, A, B, C, D);
+	T_40_59(57, D, E, A, B, C);
+	T_40_59(58, C, D, E, A, B);
+	T_40_59(59, B, C, D, E, A);
 
 	/* Round 4 */
-	T_60_79(60); T_60_79(61); T_60_79(62); T_60_79(63); T_60_79(64);
-	T_60_79(65); T_60_79(66); T_60_79(67); T_60_79(68); T_60_79(69);
-	T_60_79(70); T_60_79(71); T_60_79(72); T_60_79(73); T_60_79(74);
-	T_60_79(75); T_60_79(76); T_60_79(77); T_60_79(78); T_60_79(79);
+	T_60_79(60, A, B, C, D, E);
+	T_60_79(61, E, A, B, C, D);
+	T_60_79(62, D, E, A, B, C);
+	T_60_79(63, C, D, E, A, B);
+	T_60_79(64, B, C, D, E, A);
+	T_60_79(65, A, B, C, D, E);
+	T_60_79(66, E, A, B, C, D);
+	T_60_79(67, D, E, A, B, C);
+	T_60_79(68, C, D, E, A, B);
+	T_60_79(69, B, C, D, E, A);
+	T_60_79(70, A, B, C, D, E);
+	T_60_79(71, E, A, B, C, D);
+	T_60_79(72, D, E, A, B, C);
+	T_60_79(73, C, D, E, A, B);
+	T_60_79(74, B, C, D, E, A);
+	T_60_79(75, A, B, C, D, E);
+	T_60_79(76, E, A, B, C, D);
+	T_60_79(77, D, E, A, B, C);
+	T_60_79(78, C, D, E, A, B);
+	T_60_79(79, B, C, D, E, A);
 
 	ctx->H[0] += A;
 	ctx->H[1] += B;