*
* Copyright (C) 2005 Paul Mackerras <paulus@samba.org>
*/
-#define FS 80
/*
- * We roll the registers for T, A, B, C, D, E around on each
- * iteration; T on iteration t is A on iteration t+1, and so on.
- * We use registers 7 - 12 for this.
+ * PowerPC calling convention:
+ * %r0 - volatile temp
+ * %r1 - stack pointer.
+ * %r2 - reserved
+ * %r3-%r12 - Incoming arguments & return values; volatile.
+ * %r13-%r31 - Callee-save registers
+ * %lr - Return address, volatile
+ * %ctr - volatile
+ *
+ * Register usage in this routine:
+ * %r0 - temp
+ * %r3 - argument (pointer to 5 words of SHA state)
+ * %r4 - argument (pointer to data to hash)
+ * %r5 - Contant K in SHA round (initially number of blocks to hash)
+ * %r6-%r10 - Working copies of SHA variables A..E (actually E..A order)
+ * %r11-%r26 - Data being hashed W[].
+ * %r27-%r31 - Previous copies of A..E, for final add back.
+ * %ctr - loop count
+ */
+
+
+/*
+ * We roll the registers for A, B, C, D, E around on each
+ * iteration; E on iteration t is D on iteration t+1, and so on.
+ * We use registers 6 - 10 for this. (Registers 27 - 31 hold
+ * the previous values.)
*/
-#define RT(t) ((((t)+5)%6)+7)
-#define RA(t) ((((t)+4)%6)+7)
-#define RB(t) ((((t)+3)%6)+7)
-#define RC(t) ((((t)+2)%6)+7)
-#define RD(t) ((((t)+1)%6)+7)
-#define RE(t) ((((t)+0)%6)+7)
-
-/* We use registers 16 - 31 for the W values */
-#define W(t) (((t)%16)+16)
-
-#define STEPD0(t) \
- and %r6,RB(t),RC(t); \
- andc %r0,RD(t),RB(t); \
- rotlwi RT(t),RA(t),5; \
- rotlwi RB(t),RB(t),30; \
- or %r6,%r6,%r0; \
- add %r0,RE(t),%r15; \
- add RT(t),RT(t),%r6; \
- add %r0,%r0,W(t); \
- add RT(t),RT(t),%r0
-
-#define STEPD1(t) \
- xor %r6,RB(t),RC(t); \
- rotlwi RT(t),RA(t),5; \
- rotlwi RB(t),RB(t),30; \
- xor %r6,%r6,RD(t); \
- add %r0,RE(t),%r15; \
- add RT(t),RT(t),%r6; \
- add %r0,%r0,W(t); \
- add RT(t),RT(t),%r0
-
-#define STEPD2(t) \
- and %r6,RB(t),RC(t); \
- and %r0,RB(t),RD(t); \
- rotlwi RT(t),RA(t),5; \
- rotlwi RB(t),RB(t),30; \
- or %r6,%r6,%r0; \
- and %r0,RC(t),RD(t); \
- or %r6,%r6,%r0; \
- add %r0,RE(t),%r15; \
- add RT(t),RT(t),%r6; \
- add %r0,%r0,W(t); \
- add RT(t),RT(t),%r0
-
-#define LOADW(t) \
- lwz W(t),(t)*4(%r4)
-
-#define UPDATEW(t) \
- xor %r0,W((t)-3),W((t)-8); \
- xor W(t),W((t)-16),W((t)-14); \
- xor W(t),W(t),%r0; \
- rotlwi W(t),W(t),1
-
-#define STEP0LD4(t) \
- STEPD0(t); LOADW((t)+4); \
- STEPD0((t)+1); LOADW((t)+5); \
- STEPD0((t)+2); LOADW((t)+6); \
- STEPD0((t)+3); LOADW((t)+7)
-
-#define STEPUP4(t, fn) \
- STEP##fn(t); UPDATEW((t)+4); \
- STEP##fn((t)+1); UPDATEW((t)+5); \
- STEP##fn((t)+2); UPDATEW((t)+6); \
- STEP##fn((t)+3); UPDATEW((t)+7)
-
-#define STEPUP20(t, fn) \
- STEPUP4(t, fn); \
- STEPUP4((t)+4, fn); \
- STEPUP4((t)+8, fn); \
- STEPUP4((t)+12, fn); \
- STEPUP4((t)+16, fn)
+#define RA(t) (((t)+4)%5+6)
+#define RB(t) (((t)+3)%5+6)
+#define RC(t) (((t)+2)%5+6)
+#define RD(t) (((t)+1)%5+6)
+#define RE(t) (((t)+0)%5+6)
+
+/* We use registers 11 - 26 for the W values */
+#define W(t) ((t)%16+11)
+
+/* Register 5 is used for the constant k */
+
+/*
+ * The basic SHA-1 round function is:
+ * E += ROTL(A,5) + F(B,C,D) + W[i] + K; B = ROTL(B,30)
+ * Then the variables are renamed: (A,B,C,D,E) = (E,A,B,C,D).
+ *
+ * Every 20 rounds, the function F() and the contant K changes:
+ * - 20 rounds of f0(b,c,d) = "bit wise b ? c : d" = (^b & d) + (b & c)
+ * - 20 rounds of f1(b,c,d) = b^c^d = (b^d)^c
+ * - 20 rounds of f2(b,c,d) = majority(b,c,d) = (b&d) + ((b^d)&c)
+ * - 20 more rounds of f1(b,c,d)
+ *
+ * These are all scheduled for near-optimal performance on a G4.
+ * The G4 is a 3-issue out-of-order machine with 3 ALUs, but it can only
+ * *consider* starting the oldest 3 instructions per cycle. So to get
+ * maximum performace out of it, you have to treat it as an in-order
+ * machine. Which means interleaving the computation round t with the
+ * computation of W[t+4].
+ *
+ * The first 16 rounds use W values loaded directly from memory, while the
+ * remianing 64 use values computed from those first 16. We preload
+ * 4 values before starting, so there are three kinds of rounds:
+ * - The first 12 (all f0) also load the W values from memory.
+ * - The next 64 compute W(i+4) in parallel. 8*f0, 20*f1, 20*f2, 16*f1.
+ * - The last 4 (all f1) do not do anything with W.
+ *
+ * Therefore, we have 6 different round functions:
+ * STEPD0_LOAD(t,s) - Perform round t and load W(s). s < 16
+ * STEPD0_UPDATE(t,s) - Perform round t and compute W(s). s >= 16.
+ * STEPD1_UPDATE(t,s)
+ * STEPD2_UPDATE(t,s)
+ * STEPD1(t) - Perform round t with no load or update.
+ *
+ * The G5 is more fully out-of-order, and can find the parallelism
+ * by itself. The big limit is that it has a 2-cycle ALU latency, so
+ * even though it's 2-way, the code has to be scheduled as if it's
+ * 4-way, which can be a limit. To help it, we try to schedule the
+ * read of RA(t) as late as possible so it doesn't stall waiting for
+ * the previous round's RE(t-1), and we try to rotate RB(t) as early
+ * as possible while reading RC(t) (= RB(t-1)) as late as possible.
+ */
+
+/* the initial loads. */
+#define LOADW(s) \
+ lwz W(s),(s)*4(%r4)
+
+/*
+ * Perform a step with F0, and load W(s). Uses W(s) as a temporary
+ * before loading it.
+ * This is actually 10 instructions, which is an awkward fit.
+ * It can execute grouped as listed, or delayed one instruction.
+ * (If delayed two instructions, there is a stall before the start of the
+ * second line.) Thus, two iterations take 7 cycles, 3.5 cycles per round.
+ */
+#define STEPD0_LOAD(t,s) \
+add RE(t),RE(t),W(t); andc %r0,RD(t),RB(t); and W(s),RC(t),RB(t); \
+add RE(t),RE(t),%r0; rotlwi %r0,RA(t),5; rotlwi RB(t),RB(t),30; \
+add RE(t),RE(t),W(s); add %r0,%r0,%r5; lwz W(s),(s)*4(%r4); \
+add RE(t),RE(t),%r0
+
+/*
+ * This is likewise awkward, 13 instructions. However, it can also
+ * execute starting with 2 out of 3 possible moduli, so it does 2 rounds
+ * in 9 cycles, 4.5 cycles/round.
+ */
+#define STEPD0_UPDATE(t,s,loadk...) \
+add RE(t),RE(t),W(t); andc %r0,RD(t),RB(t); xor W(s),W((s)-16),W((s)-3); \
+add RE(t),RE(t),%r0; and %r0,RC(t),RB(t); xor W(s),W(s),W((s)-8); \
+add RE(t),RE(t),%r0; rotlwi %r0,RA(t),5; xor W(s),W(s),W((s)-14); \
+add RE(t),RE(t),%r5; loadk; rotlwi RB(t),RB(t),30; rotlwi W(s),W(s),1; \
+add RE(t),RE(t),%r0
+
+/* Nicely optimal. Conveniently, also the most common. */
+#define STEPD1_UPDATE(t,s,loadk...) \
+add RE(t),RE(t),W(t); xor %r0,RD(t),RB(t); xor W(s),W((s)-16),W((s)-3); \
+add RE(t),RE(t),%r5; loadk; xor %r0,%r0,RC(t); xor W(s),W(s),W((s)-8); \
+add RE(t),RE(t),%r0; rotlwi %r0,RA(t),5; xor W(s),W(s),W((s)-14); \
+add RE(t),RE(t),%r0; rotlwi RB(t),RB(t),30; rotlwi W(s),W(s),1
+
+/*
+ * The naked version, no UPDATE, for the last 4 rounds. 3 cycles per.
+ * We could use W(s) as a temp register, but we don't need it.
+ */
+#define STEPD1(t) \
+ add RE(t),RE(t),W(t); xor %r0,RD(t),RB(t); \
+rotlwi RB(t),RB(t),30; add RE(t),RE(t),%r5; xor %r0,%r0,RC(t); \
+add RE(t),RE(t),%r0; rotlwi %r0,RA(t),5; /* spare slot */ \
+add RE(t),RE(t),%r0
+
+/*
+ * 14 instructions, 5 cycles per. The majority function is a bit
+ * awkward to compute. This can execute with a 1-instruction delay,
+ * but it causes a 2-instruction delay, which triggers a stall.
+ */
+#define STEPD2_UPDATE(t,s,loadk...) \
+add RE(t),RE(t),W(t); and %r0,RD(t),RB(t); xor W(s),W((s)-16),W((s)-3); \
+add RE(t),RE(t),%r0; xor %r0,RD(t),RB(t); xor W(s),W(s),W((s)-8); \
+add RE(t),RE(t),%r5; loadk; and %r0,%r0,RC(t); xor W(s),W(s),W((s)-14); \
+add RE(t),RE(t),%r0; rotlwi %r0,RA(t),5; rotlwi W(s),W(s),1; \
+add RE(t),RE(t),%r0; rotlwi RB(t),RB(t),30
+
+#define STEP0_LOAD4(t,s) \
+ STEPD0_LOAD(t,s); \
+ STEPD0_LOAD((t+1),(s)+1); \
+ STEPD0_LOAD((t)+2,(s)+2); \
+ STEPD0_LOAD((t)+3,(s)+3)
+
+#define STEPUP4(fn, t, s, loadk...) \
+ STEP##fn##_UPDATE(t,s,); \
+ STEP##fn##_UPDATE((t)+1,(s)+1,); \
+ STEP##fn##_UPDATE((t)+2,(s)+2,); \
+ STEP##fn##_UPDATE((t)+3,(s)+3,loadk)
+
+#define STEPUP20(fn, t, s, loadk...) \
+ STEPUP4(fn, t, s,); \
+ STEPUP4(fn, (t)+4, (s)+4,); \
+ STEPUP4(fn, (t)+8, (s)+8,); \
+ STEPUP4(fn, (t)+12, (s)+12,); \
+ STEPUP4(fn, (t)+16, (s)+16, loadk)
.globl sha1_core
sha1_core:
- stwu %r1,-FS(%r1)
- stw %r15,FS-68(%r1)
- stw %r16,FS-64(%r1)
- stw %r17,FS-60(%r1)
- stw %r18,FS-56(%r1)
- stw %r19,FS-52(%r1)
- stw %r20,FS-48(%r1)
- stw %r21,FS-44(%r1)
- stw %r22,FS-40(%r1)
- stw %r23,FS-36(%r1)
- stw %r24,FS-32(%r1)
- stw %r25,FS-28(%r1)
- stw %r26,FS-24(%r1)
- stw %r27,FS-20(%r1)
- stw %r28,FS-16(%r1)
- stw %r29,FS-12(%r1)
- stw %r30,FS-8(%r1)
- stw %r31,FS-4(%r1)
+ stwu %r1,-80(%r1)
+ stmw %r13,4(%r1)
/* Load up A - E */
- lwz RA(0),0(%r3) /* A */
- lwz RB(0),4(%r3) /* B */
- lwz RC(0),8(%r3) /* C */
- lwz RD(0),12(%r3) /* D */
- lwz RE(0),16(%r3) /* E */
+ lmw %r27,0(%r3)
mtctr %r5
-1: LOADW(0)
+1:
+ LOADW(0)
+ lis %r5,0x5a82
+ mr RE(0),%r31
LOADW(1)
+ mr RD(0),%r30
+ mr RC(0),%r29
LOADW(2)
+ ori %r5,%r5,0x7999 /* K0-19 */
+ mr RB(0),%r28
LOADW(3)
+ mr RA(0),%r27
+
+ STEP0_LOAD4(0, 4)
+ STEP0_LOAD4(4, 8)
+ STEP0_LOAD4(8, 12)
+ STEPUP4(D0, 12, 16,)
+ STEPUP4(D0, 16, 20, lis %r5,0x6ed9)
- lis %r15,0x5a82 /* K0-19 */
- ori %r15,%r15,0x7999
- STEP0LD4(0)
- STEP0LD4(4)
- STEP0LD4(8)
- STEPUP4(12, D0)
- STEPUP4(16, D0)
-
- lis %r15,0x6ed9 /* K20-39 */
- ori %r15,%r15,0xeba1
- STEPUP20(20, D1)
-
- lis %r15,0x8f1b /* K40-59 */
- ori %r15,%r15,0xbcdc
- STEPUP20(40, D2)
-
- lis %r15,0xca62 /* K60-79 */
- ori %r15,%r15,0xc1d6
- STEPUP4(60, D1)
- STEPUP4(64, D1)
- STEPUP4(68, D1)
- STEPUP4(72, D1)
+ ori %r5,%r5,0xeba1 /* K20-39 */
+ STEPUP20(D1, 20, 24, lis %r5,0x8f1b)
+
+ ori %r5,%r5,0xbcdc /* K40-59 */
+ STEPUP20(D2, 40, 44, lis %r5,0xca62)
+
+ ori %r5,%r5,0xc1d6 /* K60-79 */
+ STEPUP4(D1, 60, 64,)
+ STEPUP4(D1, 64, 68,)
+ STEPUP4(D1, 68, 72,)
+ STEPUP4(D1, 72, 76,)
+ addi %r4,%r4,64
STEPD1(76)
STEPD1(77)
STEPD1(78)
STEPD1(79)
- lwz %r20,16(%r3)
- lwz %r19,12(%r3)
- lwz %r18,8(%r3)
- lwz %r17,4(%r3)
- lwz %r16,0(%r3)
- add %r20,RE(80),%r20
- add RD(0),RD(80),%r19
- add RC(0),RC(80),%r18
- add RB(0),RB(80),%r17
- add RA(0),RA(80),%r16
- mr RE(0),%r20
- stw RA(0),0(%r3)
- stw RB(0),4(%r3)
- stw RC(0),8(%r3)
- stw RD(0),12(%r3)
- stw RE(0),16(%r3)
+ /* Add results to original values */
+ add %r31,%r31,RE(0)
+ add %r30,%r30,RD(0)
+ add %r29,%r29,RC(0)
+ add %r28,%r28,RB(0)
+ add %r27,%r27,RA(0)
- addi %r4,%r4,64
bdnz 1b
- lwz %r15,FS-68(%r1)
- lwz %r16,FS-64(%r1)
- lwz %r17,FS-60(%r1)
- lwz %r18,FS-56(%r1)
- lwz %r19,FS-52(%r1)
- lwz %r20,FS-48(%r1)
- lwz %r21,FS-44(%r1)
- lwz %r22,FS-40(%r1)
- lwz %r23,FS-36(%r1)
- lwz %r24,FS-32(%r1)
- lwz %r25,FS-28(%r1)
- lwz %r26,FS-24(%r1)
- lwz %r27,FS-20(%r1)
- lwz %r28,FS-16(%r1)
- lwz %r29,FS-12(%r1)
- lwz %r30,FS-8(%r1)
- lwz %r31,FS-4(%r1)
- addi %r1,%r1,FS
+ /* Save final hash, restore registers, and return */
+ stmw %r27,0(%r3)
+ lmw %r13,4(%r1)
+ addi %r1,%r1,80
blr
projects / thirdparty / git.git / commitdiff
