prometheus/vendor/github.com/cespare/xxhash/xxhash_amd64.s

234 lines
4.1 KiB
ArmAsm

// +build !appengine
// +build gc
// +build !noasm
#include "textflag.h"
// Register allocation:
// AX h
// CX pointer to advance through b
// DX n
// BX loop end
// R8 v1, k1
// R9 v2
// R10 v3
// R11 v4
// R12 tmp
// R13 prime1v
// R14 prime2v
// R15 prime4v
// round reads from and advances the buffer pointer in CX.
// It assumes that R13 has prime1v and R14 has prime2v.
#define round(r) \
MOVQ (CX), R12 \
ADDQ $8, CX \
IMULQ R14, R12 \
ADDQ R12, r \
ROLQ $31, r \
IMULQ R13, r
// mergeRound applies a merge round on the two registers acc and val.
// It assumes that R13 has prime1v, R14 has prime2v, and R15 has prime4v.
#define mergeRound(acc, val) \
IMULQ R14, val \
ROLQ $31, val \
IMULQ R13, val \
XORQ val, acc \
IMULQ R13, acc \
ADDQ R15, acc
// func Sum64(b []byte) uint64
TEXT ·Sum64(SB), NOSPLIT, $0-32
// Load fixed primes.
MOVQ ·prime1v(SB), R13
MOVQ ·prime2v(SB), R14
MOVQ ·prime4v(SB), R15
// Load slice.
MOVQ b_base+0(FP), CX
MOVQ b_len+8(FP), DX
LEAQ (CX)(DX*1), BX
// The first loop limit will be len(b)-32.
SUBQ $32, BX
// Check whether we have at least one block.
CMPQ DX, $32
JLT noBlocks
// Set up initial state (v1, v2, v3, v4).
MOVQ R13, R8
ADDQ R14, R8
MOVQ R14, R9
XORQ R10, R10
XORQ R11, R11
SUBQ R13, R11
// Loop until CX > BX.
blockLoop:
round(R8)
round(R9)
round(R10)
round(R11)
CMPQ CX, BX
JLE blockLoop
MOVQ R8, AX
ROLQ $1, AX
MOVQ R9, R12
ROLQ $7, R12
ADDQ R12, AX
MOVQ R10, R12
ROLQ $12, R12
ADDQ R12, AX
MOVQ R11, R12
ROLQ $18, R12
ADDQ R12, AX
mergeRound(AX, R8)
mergeRound(AX, R9)
mergeRound(AX, R10)
mergeRound(AX, R11)
JMP afterBlocks
noBlocks:
MOVQ ·prime5v(SB), AX
afterBlocks:
ADDQ DX, AX
// Right now BX has len(b)-32, and we want to loop until CX > len(b)-8.
ADDQ $24, BX
CMPQ CX, BX
JG fourByte
wordLoop:
// Calculate k1.
MOVQ (CX), R8
ADDQ $8, CX
IMULQ R14, R8
ROLQ $31, R8
IMULQ R13, R8
XORQ R8, AX
ROLQ $27, AX
IMULQ R13, AX
ADDQ R15, AX
CMPQ CX, BX
JLE wordLoop
fourByte:
ADDQ $4, BX
CMPQ CX, BX
JG singles
MOVL (CX), R8
ADDQ $4, CX
IMULQ R13, R8
XORQ R8, AX
ROLQ $23, AX
IMULQ R14, AX
ADDQ ·prime3v(SB), AX
singles:
ADDQ $4, BX
CMPQ CX, BX
JGE finalize
singlesLoop:
MOVBQZX (CX), R12
ADDQ $1, CX
IMULQ ·prime5v(SB), R12
XORQ R12, AX
ROLQ $11, AX
IMULQ R13, AX
CMPQ CX, BX
JL singlesLoop
finalize:
MOVQ AX, R12
SHRQ $33, R12
XORQ R12, AX
IMULQ R14, AX
MOVQ AX, R12
SHRQ $29, R12
XORQ R12, AX
IMULQ ·prime3v(SB), AX
MOVQ AX, R12
SHRQ $32, R12
XORQ R12, AX
MOVQ AX, ret+24(FP)
RET
// writeBlocks uses the same registers as above except that it uses AX to store
// the x pointer.
// func writeBlocks(x *xxh, b []byte) []byte
TEXT ·writeBlocks(SB), NOSPLIT, $0-56
// Load fixed primes needed for round.
MOVQ ·prime1v(SB), R13
MOVQ ·prime2v(SB), R14
// Load slice.
MOVQ b_base+8(FP), CX
MOVQ CX, ret_base+32(FP) // initialize return base pointer; see NOTE below
MOVQ b_len+16(FP), DX
LEAQ (CX)(DX*1), BX
SUBQ $32, BX
// Load vN from x.
MOVQ x+0(FP), AX
MOVQ 0(AX), R8 // v1
MOVQ 8(AX), R9 // v2
MOVQ 16(AX), R10 // v3
MOVQ 24(AX), R11 // v4
// We don't need to check the loop condition here; this function is
// always called with at least one block of data to process.
blockLoop:
round(R8)
round(R9)
round(R10)
round(R11)
CMPQ CX, BX
JLE blockLoop
// Copy vN back to x.
MOVQ R8, 0(AX)
MOVQ R9, 8(AX)
MOVQ R10, 16(AX)
MOVQ R11, 24(AX)
// Construct return slice.
// NOTE: It's important that we don't construct a slice that has a base
// pointer off the end of the original slice, as in Go 1.7+ this will
// cause runtime crashes. (See discussion in, for example,
// https://github.com/golang/go/issues/16772.)
// Therefore, we calculate the length/cap first, and if they're zero, we
// keep the old base. This is what the compiler does as well if you
// write code like
// b = b[len(b):]
// New length is 32 - (CX - BX) -> BX+32 - CX.
ADDQ $32, BX
SUBQ CX, BX
JZ afterSetBase
MOVQ CX, ret_base+32(FP)
afterSetBase:
MOVQ BX, ret_len+40(FP)
MOVQ BX, ret_cap+48(FP) // set cap == len
RET