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//go:build !appengine && gc && !purego
// +build !appengine
// +build gc
// +build !purego
#include "textflag.h"
// Registers:
#define digest R1
#define h R2 // return value
#define p R3 // input pointer
#define n R4 // input length
#define nblocks R5 // n / 32
#define prime1 R7
#define prime2 R8
#define prime3 R9
#define prime4 R10
#define prime5 R11
#define v1 R12
#define v2 R13
#define v3 R14
#define v4 R15
#define x1 R20
#define x2 R21
#define x3 R22
#define x4 R23
#define round(acc, x) \
MADD prime2, acc, x, acc \
ROR $64-31, acc \
MUL prime1, acc
// round0 performs the operation x = round(0, x).
#define round0(x) \
MUL prime2, x \
ROR $64-31, x \
MUL prime1, x
#define mergeRound(acc, x) \
round0(x) \
EOR x, acc \
MADD acc, prime4, prime1, acc
// blockLoop processes as many 32-byte blocks as possible,
// updating v1, v2, v3, and v4. It assumes that n >= 32.
#define blockLoop() \
LSR $5, n, nblocks \
PCALIGN $16 \
loop: \
LDP.P 16(p), (x1, x2) \
LDP.P 16(p), (x3, x4) \
round(v1, x1) \
round(v2, x2) \
round(v3, x3) \
round(v4, x4) \
SUB $1, nblocks \
CBNZ nblocks, loop
// func Sum64(b []byte) uint64
TEXT ·Sum64(SB), NOSPLIT|NOFRAME, $0-32
LDP b_base+0(FP), (p, n)
LDP ·primes+0(SB), (prime1, prime2)
LDP ·primes+16(SB), (prime3, prime4)
MOVD ·primes+32(SB), prime5
CMP $32, n
CSEL LT, prime5, ZR, h // if n < 32 { h = prime5 } else { h = 0 }
BLT afterLoop
ADD prime1, prime2, v1
MOVD prime2, v2
MOVD $0, v3
NEG prime1, v4
blockLoop()
ROR $64-1, v1, x1
ROR $64-7, v2, x2
ADD x1, x2
ROR $64-12, v3, x3
ROR $64-18, v4, x4
ADD x3, x4
ADD x2, x4, h
mergeRound(h, v1)
mergeRound(h, v2)
mergeRound(h, v3)
mergeRound(h, v4)
afterLoop:
ADD n, h
TBZ $4, n, try8
LDP.P 16(p), (x1, x2)
round0(x1)
// NOTE: here and below, sequencing the EOR after the ROR (using a
// rotated register) is worth a small but measurable speedup for small
// inputs.
ROR $64-27, h
EOR x1 @> 64-27, h, h
MADD h, prime4, prime1, h
round0(x2)
ROR $64-27, h
EOR x2 @> 64-27, h, h
MADD h, prime4, prime1, h
try8:
TBZ $3, n, try4
MOVD.P 8(p), x1
round0(x1)
ROR $64-27, h
EOR x1 @> 64-27, h, h
MADD h, prime4, prime1, h
try4:
TBZ $2, n, try2
MOVWU.P 4(p), x2
MUL prime1, x2
ROR $64-23, h
EOR x2 @> 64-23, h, h
MADD h, prime3, prime2, h
try2:
TBZ $1, n, try1
MOVHU.P 2(p), x3
AND $255, x3, x1
LSR $8, x3, x2
MUL prime5, x1
ROR $64-11, h
EOR x1 @> 64-11, h, h
MUL prime1, h
MUL prime5, x2
ROR $64-11, h
EOR x2 @> 64-11, h, h
MUL prime1, h
try1:
TBZ $0, n, finalize
MOVBU (p), x4
MUL prime5, x4
ROR $64-11, h
EOR x4 @> 64-11, h, h
MUL prime1, h
finalize:
EOR h >> 33, h
MUL prime2, h
EOR h >> 29, h
MUL prime3, h
EOR h >> 32, h
MOVD h, ret+24(FP)
RET
// func writeBlocks(d *Digest, b []byte) int
TEXT ·writeBlocks(SB), NOSPLIT|NOFRAME, $0-40
LDP ·primes+0(SB), (prime1, prime2)
// Load state. Assume v[1-4] are stored contiguously.
MOVD d+0(FP), digest
LDP 0(digest), (v1, v2)
LDP 16(digest), (v3, v4)
LDP b_base+8(FP), (p, n)
blockLoop()
// Store updated state.
STP (v1, v2), 0(digest)
STP (v3, v4), 16(digest)
BIC $31, n
MOVD n, ret+32(FP)
RET
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