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// Copyright 2014 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 ppc64 ppc64le
#include "textflag.h"
// See memclrNoHeapPointers Go doc for important implementation constraints.
// func memclrNoHeapPointers(ptr unsafe.Pointer, n uintptr)
TEXT runtime·memclrNoHeapPointers(SB), NOSPLIT|NOFRAME, $0-16
MOVD ptr+0(FP), R3
MOVD n+8(FP), R4
// Determine if there are doublewords to clear
check:
ANDCC $7, R4, R5 // R5: leftover bytes to clear
SRD $3, R4, R6 // R6: double words to clear
CMP R6, $0, CR1 // CR1[EQ] set if no double words
BC 12, 6, nozerolarge // only single bytes
CMP R4, $512
BLT under512 // special case for < 512
ANDCC $127, R3, R8 // check for 128 alignment of address
BEQ zero512setup
ANDCC $7, R3, R15
BEQ zero512xsetup // at least 8 byte aligned
// zero bytes up to 8 byte alignment
ANDCC $1, R3, R15 // check for byte alignment
BEQ byte2
MOVB R0, 0(R3) // zero 1 byte
ADD $1, R3 // bump ptr by 1
ADD $-1, R4
byte2:
ANDCC $2, R3, R15 // check for 2 byte alignment
BEQ byte4
MOVH R0, 0(R3) // zero 2 bytes
ADD $2, R3 // bump ptr by 2
ADD $-2, R4
byte4:
ANDCC $4, R3, R15 // check for 4 byte alignment
BEQ zero512xsetup
MOVW R0, 0(R3) // zero 4 bytes
ADD $4, R3 // bump ptr by 4
ADD $-4, R4
BR zero512xsetup // ptr should now be 8 byte aligned
under512:
MOVD R6, CTR // R6 = number of double words
SRDCC $2, R6, R7 // 32 byte chunks?
BNE zero32setup
// Clear double words
zero8:
MOVD R0, 0(R3) // double word
ADD $8, R3
ADD $-8, R4
BC 16, 0, zero8 // dec ctr, br zero8 if ctr not 0
BR nozerolarge // handle leftovers
// Prepare to clear 32 bytes at a time.
zero32setup:
DCBTST (R3) // prepare data cache
XXLXOR VS32, VS32, VS32 // clear VS32 (V0)
MOVD R7, CTR // number of 32 byte chunks
MOVD $16, R8
zero32:
STXVD2X VS32, (R3+R0) // store 16 bytes
STXVD2X VS32, (R3+R8)
ADD $32, R3
ADD $-32, R4
BC 16, 0, zero32 // dec ctr, br zero32 if ctr not 0
RLDCLCC $61, R4, $3, R6 // remaining doublewords
BEQ nozerolarge
MOVD R6, CTR // set up the CTR for doublewords
BR zero8
nozerolarge:
ANDCC $7, R4, R5 // any remaining bytes
BC 4, 1, LR // ble lr
zerotail:
MOVD R5, CTR // set up to clear tail bytes
zerotailloop:
MOVB R0, 0(R3) // clear single bytes
ADD $1, R3
BC 16, 0, zerotailloop // dec ctr, br zerotailloop if ctr not 0
RET
zero512xsetup: // 512 chunk with extra needed
ANDCC $8, R3, R11 // 8 byte alignment?
BEQ zero512setup16
MOVD R0, 0(R3) // clear 8 bytes
ADD $8, R3 // update ptr to next 8
ADD $-8, R4 // dec count by 8
zero512setup16:
ANDCC $127, R3, R14 // < 128 byte alignment
BEQ zero512setup // handle 128 byte alignment
MOVD $128, R15
SUB R14, R15, R14 // find increment to 128 alignment
SRD $4, R14, R15 // number of 16 byte chunks
zero512presetup:
MOVD R15, CTR // loop counter of 16 bytes
XXLXOR VS32, VS32, VS32 // clear VS32 (V0)
zero512preloop: // clear up to 128 alignment
STXVD2X VS32, (R3+R0) // clear 16 bytes
ADD $16, R3 // update ptr
ADD $-16, R4 // dec count
BC 16, 0, zero512preloop
zero512setup: // setup for dcbz loop
CMP R4, $512 // check if at least 512
BLT remain
SRD $9, R4, R8 // loop count for 512 chunks
MOVD R8, CTR // set up counter
MOVD $128, R9 // index regs for 128 bytes
MOVD $256, R10
MOVD $384, R11
zero512:
DCBZ (R3+R0) // clear first chunk
DCBZ (R3+R9) // clear second chunk
DCBZ (R3+R10) // clear third chunk
DCBZ (R3+R11) // clear fourth chunk
ADD $512, R3
ADD $-512, R4
BC 16, 0, zero512
remain:
CMP R4, $128 // check if 128 byte chunks left
BLT smaller
DCBZ (R3+R0) // clear 128
ADD $128, R3
ADD $-128, R4
BR remain
smaller:
ANDCC $127, R4, R7 // find leftovers
BEQ done
CMP R7, $64 // more than 64, do 32 at a time
BLT zero8setup // less than 64, do 8 at a time
SRD $5, R7, R7 // set up counter for 32
BR zero32setup
zero8setup:
SRDCC $3, R7, R7 // less than 8 bytes
BEQ nozerolarge
MOVD R7, CTR
BR zero8
done:
RET
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