mirror of
https://github.com/superseriousbusiness/gotosocial
synced 2024-12-21 02:03:19 +00:00
722 lines
16 KiB
ArmAsm
722 lines
16 KiB
ArmAsm
// Copyright 2020 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// +build !appengine
|
|
// +build gc
|
|
// +build !noasm
|
|
|
|
#include "textflag.h"
|
|
|
|
// The asm code generally follows the pure Go code in encode_other.go, except
|
|
// where marked with a "!!!".
|
|
|
|
// ----------------------------------------------------------------------------
|
|
|
|
// func emitLiteral(dst, lit []byte) int
|
|
//
|
|
// All local variables fit into registers. The register allocation:
|
|
// - R3 len(lit)
|
|
// - R4 n
|
|
// - R6 return value
|
|
// - R8 &dst[i]
|
|
// - R10 &lit[0]
|
|
//
|
|
// The 32 bytes of stack space is to call runtime·memmove.
|
|
//
|
|
// The unusual register allocation of local variables, such as R10 for the
|
|
// source pointer, matches the allocation used at the call site in encodeBlock,
|
|
// which makes it easier to manually inline this function.
|
|
TEXT ·emitLiteral(SB), NOSPLIT, $32-56
|
|
MOVD dst_base+0(FP), R8
|
|
MOVD lit_base+24(FP), R10
|
|
MOVD lit_len+32(FP), R3
|
|
MOVD R3, R6
|
|
MOVW R3, R4
|
|
SUBW $1, R4, R4
|
|
|
|
CMPW $60, R4
|
|
BLT oneByte
|
|
CMPW $256, R4
|
|
BLT twoBytes
|
|
|
|
threeBytes:
|
|
MOVD $0xf4, R2
|
|
MOVB R2, 0(R8)
|
|
MOVW R4, 1(R8)
|
|
ADD $3, R8, R8
|
|
ADD $3, R6, R6
|
|
B memmove
|
|
|
|
twoBytes:
|
|
MOVD $0xf0, R2
|
|
MOVB R2, 0(R8)
|
|
MOVB R4, 1(R8)
|
|
ADD $2, R8, R8
|
|
ADD $2, R6, R6
|
|
B memmove
|
|
|
|
oneByte:
|
|
LSLW $2, R4, R4
|
|
MOVB R4, 0(R8)
|
|
ADD $1, R8, R8
|
|
ADD $1, R6, R6
|
|
|
|
memmove:
|
|
MOVD R6, ret+48(FP)
|
|
|
|
// copy(dst[i:], lit)
|
|
//
|
|
// This means calling runtime·memmove(&dst[i], &lit[0], len(lit)), so we push
|
|
// R8, R10 and R3 as arguments.
|
|
MOVD R8, 8(RSP)
|
|
MOVD R10, 16(RSP)
|
|
MOVD R3, 24(RSP)
|
|
CALL runtime·memmove(SB)
|
|
RET
|
|
|
|
// ----------------------------------------------------------------------------
|
|
|
|
// func emitCopy(dst []byte, offset, length int) int
|
|
//
|
|
// All local variables fit into registers. The register allocation:
|
|
// - R3 length
|
|
// - R7 &dst[0]
|
|
// - R8 &dst[i]
|
|
// - R11 offset
|
|
//
|
|
// The unusual register allocation of local variables, such as R11 for the
|
|
// offset, matches the allocation used at the call site in encodeBlock, which
|
|
// makes it easier to manually inline this function.
|
|
TEXT ·emitCopy(SB), NOSPLIT, $0-48
|
|
MOVD dst_base+0(FP), R8
|
|
MOVD R8, R7
|
|
MOVD offset+24(FP), R11
|
|
MOVD length+32(FP), R3
|
|
|
|
loop0:
|
|
// for length >= 68 { etc }
|
|
CMPW $68, R3
|
|
BLT step1
|
|
|
|
// Emit a length 64 copy, encoded as 3 bytes.
|
|
MOVD $0xfe, R2
|
|
MOVB R2, 0(R8)
|
|
MOVW R11, 1(R8)
|
|
ADD $3, R8, R8
|
|
SUB $64, R3, R3
|
|
B loop0
|
|
|
|
step1:
|
|
// if length > 64 { etc }
|
|
CMP $64, R3
|
|
BLE step2
|
|
|
|
// Emit a length 60 copy, encoded as 3 bytes.
|
|
MOVD $0xee, R2
|
|
MOVB R2, 0(R8)
|
|
MOVW R11, 1(R8)
|
|
ADD $3, R8, R8
|
|
SUB $60, R3, R3
|
|
|
|
step2:
|
|
// if length >= 12 || offset >= 2048 { goto step3 }
|
|
CMP $12, R3
|
|
BGE step3
|
|
CMPW $2048, R11
|
|
BGE step3
|
|
|
|
// Emit the remaining copy, encoded as 2 bytes.
|
|
MOVB R11, 1(R8)
|
|
LSRW $3, R11, R11
|
|
AND $0xe0, R11, R11
|
|
SUB $4, R3, R3
|
|
LSLW $2, R3
|
|
AND $0xff, R3, R3
|
|
ORRW R3, R11, R11
|
|
ORRW $1, R11, R11
|
|
MOVB R11, 0(R8)
|
|
ADD $2, R8, R8
|
|
|
|
// Return the number of bytes written.
|
|
SUB R7, R8, R8
|
|
MOVD R8, ret+40(FP)
|
|
RET
|
|
|
|
step3:
|
|
// Emit the remaining copy, encoded as 3 bytes.
|
|
SUB $1, R3, R3
|
|
AND $0xff, R3, R3
|
|
LSLW $2, R3, R3
|
|
ORRW $2, R3, R3
|
|
MOVB R3, 0(R8)
|
|
MOVW R11, 1(R8)
|
|
ADD $3, R8, R8
|
|
|
|
// Return the number of bytes written.
|
|
SUB R7, R8, R8
|
|
MOVD R8, ret+40(FP)
|
|
RET
|
|
|
|
// ----------------------------------------------------------------------------
|
|
|
|
// func extendMatch(src []byte, i, j int) int
|
|
//
|
|
// All local variables fit into registers. The register allocation:
|
|
// - R6 &src[0]
|
|
// - R7 &src[j]
|
|
// - R13 &src[len(src) - 8]
|
|
// - R14 &src[len(src)]
|
|
// - R15 &src[i]
|
|
//
|
|
// The unusual register allocation of local variables, such as R15 for a source
|
|
// pointer, matches the allocation used at the call site in encodeBlock, which
|
|
// makes it easier to manually inline this function.
|
|
TEXT ·extendMatch(SB), NOSPLIT, $0-48
|
|
MOVD src_base+0(FP), R6
|
|
MOVD src_len+8(FP), R14
|
|
MOVD i+24(FP), R15
|
|
MOVD j+32(FP), R7
|
|
ADD R6, R14, R14
|
|
ADD R6, R15, R15
|
|
ADD R6, R7, R7
|
|
MOVD R14, R13
|
|
SUB $8, R13, R13
|
|
|
|
cmp8:
|
|
// As long as we are 8 or more bytes before the end of src, we can load and
|
|
// compare 8 bytes at a time. If those 8 bytes are equal, repeat.
|
|
CMP R13, R7
|
|
BHI cmp1
|
|
MOVD (R15), R3
|
|
MOVD (R7), R4
|
|
CMP R4, R3
|
|
BNE bsf
|
|
ADD $8, R15, R15
|
|
ADD $8, R7, R7
|
|
B cmp8
|
|
|
|
bsf:
|
|
// If those 8 bytes were not equal, XOR the two 8 byte values, and return
|
|
// the index of the first byte that differs.
|
|
// RBIT reverses the bit order, then CLZ counts the leading zeros, the
|
|
// combination of which finds the least significant bit which is set.
|
|
// The arm64 architecture is little-endian, and the shift by 3 converts
|
|
// a bit index to a byte index.
|
|
EOR R3, R4, R4
|
|
RBIT R4, R4
|
|
CLZ R4, R4
|
|
ADD R4>>3, R7, R7
|
|
|
|
// Convert from &src[ret] to ret.
|
|
SUB R6, R7, R7
|
|
MOVD R7, ret+40(FP)
|
|
RET
|
|
|
|
cmp1:
|
|
// In src's tail, compare 1 byte at a time.
|
|
CMP R7, R14
|
|
BLS extendMatchEnd
|
|
MOVB (R15), R3
|
|
MOVB (R7), R4
|
|
CMP R4, R3
|
|
BNE extendMatchEnd
|
|
ADD $1, R15, R15
|
|
ADD $1, R7, R7
|
|
B cmp1
|
|
|
|
extendMatchEnd:
|
|
// Convert from &src[ret] to ret.
|
|
SUB R6, R7, R7
|
|
MOVD R7, ret+40(FP)
|
|
RET
|
|
|
|
// ----------------------------------------------------------------------------
|
|
|
|
// func encodeBlock(dst, src []byte) (d int)
|
|
//
|
|
// All local variables fit into registers, other than "var table". The register
|
|
// allocation:
|
|
// - R3 . .
|
|
// - R4 . .
|
|
// - R5 64 shift
|
|
// - R6 72 &src[0], tableSize
|
|
// - R7 80 &src[s]
|
|
// - R8 88 &dst[d]
|
|
// - R9 96 sLimit
|
|
// - R10 . &src[nextEmit]
|
|
// - R11 104 prevHash, currHash, nextHash, offset
|
|
// - R12 112 &src[base], skip
|
|
// - R13 . &src[nextS], &src[len(src) - 8]
|
|
// - R14 . len(src), bytesBetweenHashLookups, &src[len(src)], x
|
|
// - R15 120 candidate
|
|
// - R16 . hash constant, 0x1e35a7bd
|
|
// - R17 . &table
|
|
// - . 128 table
|
|
//
|
|
// The second column (64, 72, etc) is the stack offset to spill the registers
|
|
// when calling other functions. We could pack this slightly tighter, but it's
|
|
// simpler to have a dedicated spill map independent of the function called.
|
|
//
|
|
// "var table [maxTableSize]uint16" takes up 32768 bytes of stack space. An
|
|
// extra 64 bytes, to call other functions, and an extra 64 bytes, to spill
|
|
// local variables (registers) during calls gives 32768 + 64 + 64 = 32896.
|
|
TEXT ·encodeBlock(SB), 0, $32896-56
|
|
MOVD dst_base+0(FP), R8
|
|
MOVD src_base+24(FP), R7
|
|
MOVD src_len+32(FP), R14
|
|
|
|
// shift, tableSize := uint32(32-8), 1<<8
|
|
MOVD $24, R5
|
|
MOVD $256, R6
|
|
MOVW $0xa7bd, R16
|
|
MOVKW $(0x1e35<<16), R16
|
|
|
|
calcShift:
|
|
// for ; tableSize < maxTableSize && tableSize < len(src); tableSize *= 2 {
|
|
// shift--
|
|
// }
|
|
MOVD $16384, R2
|
|
CMP R2, R6
|
|
BGE varTable
|
|
CMP R14, R6
|
|
BGE varTable
|
|
SUB $1, R5, R5
|
|
LSL $1, R6, R6
|
|
B calcShift
|
|
|
|
varTable:
|
|
// var table [maxTableSize]uint16
|
|
//
|
|
// In the asm code, unlike the Go code, we can zero-initialize only the
|
|
// first tableSize elements. Each uint16 element is 2 bytes and each
|
|
// iterations writes 64 bytes, so we can do only tableSize/32 writes
|
|
// instead of the 2048 writes that would zero-initialize all of table's
|
|
// 32768 bytes. This clear could overrun the first tableSize elements, but
|
|
// it won't overrun the allocated stack size.
|
|
ADD $128, RSP, R17
|
|
MOVD R17, R4
|
|
|
|
// !!! R6 = &src[tableSize]
|
|
ADD R6<<1, R17, R6
|
|
|
|
memclr:
|
|
STP.P (ZR, ZR), 64(R4)
|
|
STP (ZR, ZR), -48(R4)
|
|
STP (ZR, ZR), -32(R4)
|
|
STP (ZR, ZR), -16(R4)
|
|
CMP R4, R6
|
|
BHI memclr
|
|
|
|
// !!! R6 = &src[0]
|
|
MOVD R7, R6
|
|
|
|
// sLimit := len(src) - inputMargin
|
|
MOVD R14, R9
|
|
SUB $15, R9, R9
|
|
|
|
// !!! Pre-emptively spill R5, R6 and R9 to the stack. Their values don't
|
|
// change for the rest of the function.
|
|
MOVD R5, 64(RSP)
|
|
MOVD R6, 72(RSP)
|
|
MOVD R9, 96(RSP)
|
|
|
|
// nextEmit := 0
|
|
MOVD R6, R10
|
|
|
|
// s := 1
|
|
ADD $1, R7, R7
|
|
|
|
// nextHash := hash(load32(src, s), shift)
|
|
MOVW 0(R7), R11
|
|
MULW R16, R11, R11
|
|
LSRW R5, R11, R11
|
|
|
|
outer:
|
|
// for { etc }
|
|
|
|
// skip := 32
|
|
MOVD $32, R12
|
|
|
|
// nextS := s
|
|
MOVD R7, R13
|
|
|
|
// candidate := 0
|
|
MOVD $0, R15
|
|
|
|
inner0:
|
|
// for { etc }
|
|
|
|
// s := nextS
|
|
MOVD R13, R7
|
|
|
|
// bytesBetweenHashLookups := skip >> 5
|
|
MOVD R12, R14
|
|
LSR $5, R14, R14
|
|
|
|
// nextS = s + bytesBetweenHashLookups
|
|
ADD R14, R13, R13
|
|
|
|
// skip += bytesBetweenHashLookups
|
|
ADD R14, R12, R12
|
|
|
|
// if nextS > sLimit { goto emitRemainder }
|
|
MOVD R13, R3
|
|
SUB R6, R3, R3
|
|
CMP R9, R3
|
|
BHI emitRemainder
|
|
|
|
// candidate = int(table[nextHash])
|
|
MOVHU 0(R17)(R11<<1), R15
|
|
|
|
// table[nextHash] = uint16(s)
|
|
MOVD R7, R3
|
|
SUB R6, R3, R3
|
|
|
|
MOVH R3, 0(R17)(R11<<1)
|
|
|
|
// nextHash = hash(load32(src, nextS), shift)
|
|
MOVW 0(R13), R11
|
|
MULW R16, R11
|
|
LSRW R5, R11, R11
|
|
|
|
// if load32(src, s) != load32(src, candidate) { continue } break
|
|
MOVW 0(R7), R3
|
|
MOVW (R6)(R15*1), R4
|
|
CMPW R4, R3
|
|
BNE inner0
|
|
|
|
fourByteMatch:
|
|
// As per the encode_other.go code:
|
|
//
|
|
// A 4-byte match has been found. We'll later see etc.
|
|
|
|
// !!! Jump to a fast path for short (<= 16 byte) literals. See the comment
|
|
// on inputMargin in encode.go.
|
|
MOVD R7, R3
|
|
SUB R10, R3, R3
|
|
CMP $16, R3
|
|
BLE emitLiteralFastPath
|
|
|
|
// ----------------------------------------
|
|
// Begin inline of the emitLiteral call.
|
|
//
|
|
// d += emitLiteral(dst[d:], src[nextEmit:s])
|
|
|
|
MOVW R3, R4
|
|
SUBW $1, R4, R4
|
|
|
|
MOVW $60, R2
|
|
CMPW R2, R4
|
|
BLT inlineEmitLiteralOneByte
|
|
MOVW $256, R2
|
|
CMPW R2, R4
|
|
BLT inlineEmitLiteralTwoBytes
|
|
|
|
inlineEmitLiteralThreeBytes:
|
|
MOVD $0xf4, R1
|
|
MOVB R1, 0(R8)
|
|
MOVW R4, 1(R8)
|
|
ADD $3, R8, R8
|
|
B inlineEmitLiteralMemmove
|
|
|
|
inlineEmitLiteralTwoBytes:
|
|
MOVD $0xf0, R1
|
|
MOVB R1, 0(R8)
|
|
MOVB R4, 1(R8)
|
|
ADD $2, R8, R8
|
|
B inlineEmitLiteralMemmove
|
|
|
|
inlineEmitLiteralOneByte:
|
|
LSLW $2, R4, R4
|
|
MOVB R4, 0(R8)
|
|
ADD $1, R8, R8
|
|
|
|
inlineEmitLiteralMemmove:
|
|
// Spill local variables (registers) onto the stack; call; unspill.
|
|
//
|
|
// copy(dst[i:], lit)
|
|
//
|
|
// This means calling runtime·memmove(&dst[i], &lit[0], len(lit)), so we push
|
|
// R8, R10 and R3 as arguments.
|
|
MOVD R8, 8(RSP)
|
|
MOVD R10, 16(RSP)
|
|
MOVD R3, 24(RSP)
|
|
|
|
// Finish the "d +=" part of "d += emitLiteral(etc)".
|
|
ADD R3, R8, R8
|
|
MOVD R7, 80(RSP)
|
|
MOVD R8, 88(RSP)
|
|
MOVD R15, 120(RSP)
|
|
CALL runtime·memmove(SB)
|
|
MOVD 64(RSP), R5
|
|
MOVD 72(RSP), R6
|
|
MOVD 80(RSP), R7
|
|
MOVD 88(RSP), R8
|
|
MOVD 96(RSP), R9
|
|
MOVD 120(RSP), R15
|
|
ADD $128, RSP, R17
|
|
MOVW $0xa7bd, R16
|
|
MOVKW $(0x1e35<<16), R16
|
|
B inner1
|
|
|
|
inlineEmitLiteralEnd:
|
|
// End inline of the emitLiteral call.
|
|
// ----------------------------------------
|
|
|
|
emitLiteralFastPath:
|
|
// !!! Emit the 1-byte encoding "uint8(len(lit)-1)<<2".
|
|
MOVB R3, R4
|
|
SUBW $1, R4, R4
|
|
AND $0xff, R4, R4
|
|
LSLW $2, R4, R4
|
|
MOVB R4, (R8)
|
|
ADD $1, R8, R8
|
|
|
|
// !!! Implement the copy from lit to dst as a 16-byte load and store.
|
|
// (Encode's documentation says that dst and src must not overlap.)
|
|
//
|
|
// This always copies 16 bytes, instead of only len(lit) bytes, but that's
|
|
// OK. Subsequent iterations will fix up the overrun.
|
|
//
|
|
// Note that on arm64, it is legal and cheap to issue unaligned 8-byte or
|
|
// 16-byte loads and stores. This technique probably wouldn't be as
|
|
// effective on architectures that are fussier about alignment.
|
|
LDP 0(R10), (R0, R1)
|
|
STP (R0, R1), 0(R8)
|
|
ADD R3, R8, R8
|
|
|
|
inner1:
|
|
// for { etc }
|
|
|
|
// base := s
|
|
MOVD R7, R12
|
|
|
|
// !!! offset := base - candidate
|
|
MOVD R12, R11
|
|
SUB R15, R11, R11
|
|
SUB R6, R11, R11
|
|
|
|
// ----------------------------------------
|
|
// Begin inline of the extendMatch call.
|
|
//
|
|
// s = extendMatch(src, candidate+4, s+4)
|
|
|
|
// !!! R14 = &src[len(src)]
|
|
MOVD src_len+32(FP), R14
|
|
ADD R6, R14, R14
|
|
|
|
// !!! R13 = &src[len(src) - 8]
|
|
MOVD R14, R13
|
|
SUB $8, R13, R13
|
|
|
|
// !!! R15 = &src[candidate + 4]
|
|
ADD $4, R15, R15
|
|
ADD R6, R15, R15
|
|
|
|
// !!! s += 4
|
|
ADD $4, R7, R7
|
|
|
|
inlineExtendMatchCmp8:
|
|
// As long as we are 8 or more bytes before the end of src, we can load and
|
|
// compare 8 bytes at a time. If those 8 bytes are equal, repeat.
|
|
CMP R13, R7
|
|
BHI inlineExtendMatchCmp1
|
|
MOVD (R15), R3
|
|
MOVD (R7), R4
|
|
CMP R4, R3
|
|
BNE inlineExtendMatchBSF
|
|
ADD $8, R15, R15
|
|
ADD $8, R7, R7
|
|
B inlineExtendMatchCmp8
|
|
|
|
inlineExtendMatchBSF:
|
|
// If those 8 bytes were not equal, XOR the two 8 byte values, and return
|
|
// the index of the first byte that differs.
|
|
// RBIT reverses the bit order, then CLZ counts the leading zeros, the
|
|
// combination of which finds the least significant bit which is set.
|
|
// The arm64 architecture is little-endian, and the shift by 3 converts
|
|
// a bit index to a byte index.
|
|
EOR R3, R4, R4
|
|
RBIT R4, R4
|
|
CLZ R4, R4
|
|
ADD R4>>3, R7, R7
|
|
B inlineExtendMatchEnd
|
|
|
|
inlineExtendMatchCmp1:
|
|
// In src's tail, compare 1 byte at a time.
|
|
CMP R7, R14
|
|
BLS inlineExtendMatchEnd
|
|
MOVB (R15), R3
|
|
MOVB (R7), R4
|
|
CMP R4, R3
|
|
BNE inlineExtendMatchEnd
|
|
ADD $1, R15, R15
|
|
ADD $1, R7, R7
|
|
B inlineExtendMatchCmp1
|
|
|
|
inlineExtendMatchEnd:
|
|
// End inline of the extendMatch call.
|
|
// ----------------------------------------
|
|
|
|
// ----------------------------------------
|
|
// Begin inline of the emitCopy call.
|
|
//
|
|
// d += emitCopy(dst[d:], base-candidate, s-base)
|
|
|
|
// !!! length := s - base
|
|
MOVD R7, R3
|
|
SUB R12, R3, R3
|
|
|
|
inlineEmitCopyLoop0:
|
|
// for length >= 68 { etc }
|
|
MOVW $68, R2
|
|
CMPW R2, R3
|
|
BLT inlineEmitCopyStep1
|
|
|
|
// Emit a length 64 copy, encoded as 3 bytes.
|
|
MOVD $0xfe, R1
|
|
MOVB R1, 0(R8)
|
|
MOVW R11, 1(R8)
|
|
ADD $3, R8, R8
|
|
SUBW $64, R3, R3
|
|
B inlineEmitCopyLoop0
|
|
|
|
inlineEmitCopyStep1:
|
|
// if length > 64 { etc }
|
|
MOVW $64, R2
|
|
CMPW R2, R3
|
|
BLE inlineEmitCopyStep2
|
|
|
|
// Emit a length 60 copy, encoded as 3 bytes.
|
|
MOVD $0xee, R1
|
|
MOVB R1, 0(R8)
|
|
MOVW R11, 1(R8)
|
|
ADD $3, R8, R8
|
|
SUBW $60, R3, R3
|
|
|
|
inlineEmitCopyStep2:
|
|
// if length >= 12 || offset >= 2048 { goto inlineEmitCopyStep3 }
|
|
MOVW $12, R2
|
|
CMPW R2, R3
|
|
BGE inlineEmitCopyStep3
|
|
MOVW $2048, R2
|
|
CMPW R2, R11
|
|
BGE inlineEmitCopyStep3
|
|
|
|
// Emit the remaining copy, encoded as 2 bytes.
|
|
MOVB R11, 1(R8)
|
|
LSRW $8, R11, R11
|
|
LSLW $5, R11, R11
|
|
SUBW $4, R3, R3
|
|
AND $0xff, R3, R3
|
|
LSLW $2, R3, R3
|
|
ORRW R3, R11, R11
|
|
ORRW $1, R11, R11
|
|
MOVB R11, 0(R8)
|
|
ADD $2, R8, R8
|
|
B inlineEmitCopyEnd
|
|
|
|
inlineEmitCopyStep3:
|
|
// Emit the remaining copy, encoded as 3 bytes.
|
|
SUBW $1, R3, R3
|
|
LSLW $2, R3, R3
|
|
ORRW $2, R3, R3
|
|
MOVB R3, 0(R8)
|
|
MOVW R11, 1(R8)
|
|
ADD $3, R8, R8
|
|
|
|
inlineEmitCopyEnd:
|
|
// End inline of the emitCopy call.
|
|
// ----------------------------------------
|
|
|
|
// nextEmit = s
|
|
MOVD R7, R10
|
|
|
|
// if s >= sLimit { goto emitRemainder }
|
|
MOVD R7, R3
|
|
SUB R6, R3, R3
|
|
CMP R3, R9
|
|
BLS emitRemainder
|
|
|
|
// As per the encode_other.go code:
|
|
//
|
|
// We could immediately etc.
|
|
|
|
// x := load64(src, s-1)
|
|
MOVD -1(R7), R14
|
|
|
|
// prevHash := hash(uint32(x>>0), shift)
|
|
MOVW R14, R11
|
|
MULW R16, R11, R11
|
|
LSRW R5, R11, R11
|
|
|
|
// table[prevHash] = uint16(s-1)
|
|
MOVD R7, R3
|
|
SUB R6, R3, R3
|
|
SUB $1, R3, R3
|
|
|
|
MOVHU R3, 0(R17)(R11<<1)
|
|
|
|
// currHash := hash(uint32(x>>8), shift)
|
|
LSR $8, R14, R14
|
|
MOVW R14, R11
|
|
MULW R16, R11, R11
|
|
LSRW R5, R11, R11
|
|
|
|
// candidate = int(table[currHash])
|
|
MOVHU 0(R17)(R11<<1), R15
|
|
|
|
// table[currHash] = uint16(s)
|
|
ADD $1, R3, R3
|
|
MOVHU R3, 0(R17)(R11<<1)
|
|
|
|
// if uint32(x>>8) == load32(src, candidate) { continue }
|
|
MOVW (R6)(R15*1), R4
|
|
CMPW R4, R14
|
|
BEQ inner1
|
|
|
|
// nextHash = hash(uint32(x>>16), shift)
|
|
LSR $8, R14, R14
|
|
MOVW R14, R11
|
|
MULW R16, R11, R11
|
|
LSRW R5, R11, R11
|
|
|
|
// s++
|
|
ADD $1, R7, R7
|
|
|
|
// break out of the inner1 for loop, i.e. continue the outer loop.
|
|
B outer
|
|
|
|
emitRemainder:
|
|
// if nextEmit < len(src) { etc }
|
|
MOVD src_len+32(FP), R3
|
|
ADD R6, R3, R3
|
|
CMP R3, R10
|
|
BEQ encodeBlockEnd
|
|
|
|
// d += emitLiteral(dst[d:], src[nextEmit:])
|
|
//
|
|
// Push args.
|
|
MOVD R8, 8(RSP)
|
|
MOVD $0, 16(RSP) // Unnecessary, as the callee ignores it, but conservative.
|
|
MOVD $0, 24(RSP) // Unnecessary, as the callee ignores it, but conservative.
|
|
MOVD R10, 32(RSP)
|
|
SUB R10, R3, R3
|
|
MOVD R3, 40(RSP)
|
|
MOVD R3, 48(RSP) // Unnecessary, as the callee ignores it, but conservative.
|
|
|
|
// Spill local variables (registers) onto the stack; call; unspill.
|
|
MOVD R8, 88(RSP)
|
|
CALL ·emitLiteral(SB)
|
|
MOVD 88(RSP), R8
|
|
|
|
// Finish the "d +=" part of "d += emitLiteral(etc)".
|
|
MOVD 56(RSP), R1
|
|
ADD R1, R8, R8
|
|
|
|
encodeBlockEnd:
|
|
MOVD dst_base+0(FP), R3
|
|
SUB R3, R8, R8
|
|
MOVD R8, d+48(FP)
|
|
RET
|