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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:25:22 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-16 19:25:22 +0000
commitf6ad4dcef54c5ce997a4bad5a6d86de229015700 (patch)
tree7cfa4e31ace5c2bd95c72b154d15af494b2bcbef /src/runtime/internal/atomic/atomic_riscv64.s
parentInitial commit. (diff)
downloadgolang-1.22-f6ad4dcef54c5ce997a4bad5a6d86de229015700.tar.xz
golang-1.22-f6ad4dcef54c5ce997a4bad5a6d86de229015700.zip
Adding upstream version 1.22.1.upstream/1.22.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/runtime/internal/atomic/atomic_riscv64.s')
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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.
+
+// RISC-V's atomic operations have two bits, aq ("acquire") and rl ("release"),
+// which may be toggled on and off. Their precise semantics are defined in
+// section 6.3 of the specification, but the basic idea is as follows:
+//
+// - If neither aq nor rl is set, the CPU may reorder the atomic arbitrarily.
+// It guarantees only that it will execute atomically.
+//
+// - If aq is set, the CPU may move the instruction backward, but not forward.
+//
+// - If rl is set, the CPU may move the instruction forward, but not backward.
+//
+// - If both are set, the CPU may not reorder the instruction at all.
+//
+// These four modes correspond to other well-known memory models on other CPUs.
+// On ARM, aq corresponds to a dmb ishst, aq+rl corresponds to a dmb ish. On
+// Intel, aq corresponds to an lfence, rl to an sfence, and aq+rl to an mfence
+// (or a lock prefix).
+//
+// Go's memory model requires that
+// - if a read happens after a write, the read must observe the write, and
+// that
+// - if a read happens concurrently with a write, the read may observe the
+// write.
+// aq is sufficient to guarantee this, so that's what we use here. (This jibes
+// with ARM, which uses dmb ishst.)
+
+#include "textflag.h"
+
+// func Cas(ptr *uint64, old, new uint64) bool
+// Atomically:
+// if(*val == old){
+// *val = new;
+// return 1;
+// } else {
+// return 0;
+// }
+TEXT ·Cas(SB), NOSPLIT, $0-17
+ MOV ptr+0(FP), A0
+ MOVW old+8(FP), A1
+ MOVW new+12(FP), A2
+cas_again:
+ LRW (A0), A3
+ BNE A3, A1, cas_fail
+ SCW A2, (A0), A4
+ BNE A4, ZERO, cas_again
+ MOV $1, A0
+ MOVB A0, ret+16(FP)
+ RET
+cas_fail:
+ MOV $0, A0
+ MOV A0, ret+16(FP)
+ RET
+
+// func Cas64(ptr *uint64, old, new uint64) bool
+TEXT ·Cas64(SB), NOSPLIT, $0-25
+ MOV ptr+0(FP), A0
+ MOV old+8(FP), A1
+ MOV new+16(FP), A2
+cas_again:
+ LRD (A0), A3
+ BNE A3, A1, cas_fail
+ SCD A2, (A0), A4
+ BNE A4, ZERO, cas_again
+ MOV $1, A0
+ MOVB A0, ret+24(FP)
+ RET
+cas_fail:
+ MOVB ZERO, ret+24(FP)
+ RET
+
+// func Load(ptr *uint32) uint32
+TEXT ·Load(SB),NOSPLIT|NOFRAME,$0-12
+ MOV ptr+0(FP), A0
+ LRW (A0), A0
+ MOVW A0, ret+8(FP)
+ RET
+
+// func Load8(ptr *uint8) uint8
+TEXT ·Load8(SB),NOSPLIT|NOFRAME,$0-9
+ MOV ptr+0(FP), A0
+ FENCE
+ MOVBU (A0), A1
+ FENCE
+ MOVB A1, ret+8(FP)
+ RET
+
+// func Load64(ptr *uint64) uint64
+TEXT ·Load64(SB),NOSPLIT|NOFRAME,$0-16
+ MOV ptr+0(FP), A0
+ LRD (A0), A0
+ MOV A0, ret+8(FP)
+ RET
+
+// func Store(ptr *uint32, val uint32)
+TEXT ·Store(SB), NOSPLIT, $0-12
+ MOV ptr+0(FP), A0
+ MOVW val+8(FP), A1
+ AMOSWAPW A1, (A0), ZERO
+ RET
+
+// func Store8(ptr *uint8, val uint8)
+TEXT ·Store8(SB), NOSPLIT, $0-9
+ MOV ptr+0(FP), A0
+ MOVBU val+8(FP), A1
+ FENCE
+ MOVB A1, (A0)
+ FENCE
+ RET
+
+// func Store64(ptr *uint64, val uint64)
+TEXT ·Store64(SB), NOSPLIT, $0-16
+ MOV ptr+0(FP), A0
+ MOV val+8(FP), A1
+ AMOSWAPD A1, (A0), ZERO
+ RET
+
+TEXT ·Casp1(SB), NOSPLIT, $0-25
+ JMP ·Cas64(SB)
+
+TEXT ·Casint32(SB),NOSPLIT,$0-17
+ JMP ·Cas(SB)
+
+TEXT ·Casint64(SB),NOSPLIT,$0-25
+ JMP ·Cas64(SB)
+
+TEXT ·Casuintptr(SB),NOSPLIT,$0-25
+ JMP ·Cas64(SB)
+
+TEXT ·CasRel(SB), NOSPLIT, $0-17
+ JMP ·Cas(SB)
+
+TEXT ·Loaduintptr(SB),NOSPLIT,$0-16
+ JMP ·Load64(SB)
+
+TEXT ·Storeint32(SB),NOSPLIT,$0-12
+ JMP ·Store(SB)
+
+TEXT ·Storeint64(SB),NOSPLIT,$0-16
+ JMP ·Store64(SB)
+
+TEXT ·Storeuintptr(SB),NOSPLIT,$0-16
+ JMP ·Store64(SB)
+
+TEXT ·Loaduint(SB),NOSPLIT,$0-16
+ JMP ·Loaduintptr(SB)
+
+TEXT ·Loadint32(SB),NOSPLIT,$0-12
+ JMP ·Load(SB)
+
+TEXT ·Loadint64(SB),NOSPLIT,$0-16
+ JMP ·Load64(SB)
+
+TEXT ·Xaddint32(SB),NOSPLIT,$0-20
+ JMP ·Xadd(SB)
+
+TEXT ·Xaddint64(SB),NOSPLIT,$0-24
+ MOV ptr+0(FP), A0
+ MOV delta+8(FP), A1
+ AMOADDD A1, (A0), A0
+ ADD A0, A1, A0
+ MOVW A0, ret+16(FP)
+ RET
+
+TEXT ·LoadAcq(SB),NOSPLIT|NOFRAME,$0-12
+ JMP ·Load(SB)
+
+TEXT ·LoadAcq64(SB),NOSPLIT|NOFRAME,$0-16
+ JMP ·Load64(SB)
+
+TEXT ·LoadAcquintptr(SB),NOSPLIT|NOFRAME,$0-16
+ JMP ·Load64(SB)
+
+// func Loadp(ptr unsafe.Pointer) unsafe.Pointer
+TEXT ·Loadp(SB),NOSPLIT,$0-16
+ JMP ·Load64(SB)
+
+// func StorepNoWB(ptr unsafe.Pointer, val unsafe.Pointer)
+TEXT ·StorepNoWB(SB), NOSPLIT, $0-16
+ JMP ·Store64(SB)
+
+TEXT ·StoreRel(SB), NOSPLIT, $0-12
+ JMP ·Store(SB)
+
+TEXT ·StoreRel64(SB), NOSPLIT, $0-16
+ JMP ·Store64(SB)
+
+TEXT ·StoreReluintptr(SB), NOSPLIT, $0-16
+ JMP ·Store64(SB)
+
+// func Xchg(ptr *uint32, new uint32) uint32
+TEXT ·Xchg(SB), NOSPLIT, $0-20
+ MOV ptr+0(FP), A0
+ MOVW new+8(FP), A1
+ AMOSWAPW A1, (A0), A1
+ MOVW A1, ret+16(FP)
+ RET
+
+// func Xchg64(ptr *uint64, new uint64) uint64
+TEXT ·Xchg64(SB), NOSPLIT, $0-24
+ MOV ptr+0(FP), A0
+ MOV new+8(FP), A1
+ AMOSWAPD A1, (A0), A1
+ MOV A1, ret+16(FP)
+ RET
+
+// Atomically:
+// *val += delta;
+// return *val;
+
+// func Xadd(ptr *uint32, delta int32) uint32
+TEXT ·Xadd(SB), NOSPLIT, $0-20
+ MOV ptr+0(FP), A0
+ MOVW delta+8(FP), A1
+ AMOADDW A1, (A0), A2
+ ADD A2,A1,A0
+ MOVW A0, ret+16(FP)
+ RET
+
+// func Xadd64(ptr *uint64, delta int64) uint64
+TEXT ·Xadd64(SB), NOSPLIT, $0-24
+ MOV ptr+0(FP), A0
+ MOV delta+8(FP), A1
+ AMOADDD A1, (A0), A2
+ ADD A2, A1, A0
+ MOV A0, ret+16(FP)
+ RET
+
+// func Xadduintptr(ptr *uintptr, delta uintptr) uintptr
+TEXT ·Xadduintptr(SB), NOSPLIT, $0-24
+ JMP ·Xadd64(SB)
+
+// func Xchgint32(ptr *int32, new int32) int32
+TEXT ·Xchgint32(SB), NOSPLIT, $0-20
+ JMP ·Xchg(SB)
+
+// func Xchgint64(ptr *int64, new int64) int64
+TEXT ·Xchgint64(SB), NOSPLIT, $0-24
+ JMP ·Xchg64(SB)
+
+// func Xchguintptr(ptr *uintptr, new uintptr) uintptr
+TEXT ·Xchguintptr(SB), NOSPLIT, $0-24
+ JMP ·Xchg64(SB)
+
+// func And8(ptr *uint8, val uint8)
+TEXT ·And8(SB), NOSPLIT, $0-9
+ MOV ptr+0(FP), A0
+ MOVBU val+8(FP), A1
+ AND $3, A0, A2
+ AND $-4, A0
+ SLL $3, A2
+ XOR $255, A1
+ SLL A2, A1
+ XOR $-1, A1
+ AMOANDW A1, (A0), ZERO
+ RET
+
+// func Or8(ptr *uint8, val uint8)
+TEXT ·Or8(SB), NOSPLIT, $0-9
+ MOV ptr+0(FP), A0
+ MOVBU val+8(FP), A1
+ AND $3, A0, A2
+ AND $-4, A0
+ SLL $3, A2
+ SLL A2, A1
+ AMOORW A1, (A0), ZERO
+ RET
+
+// func And(ptr *uint32, val uint32)
+TEXT ·And(SB), NOSPLIT, $0-12
+ MOV ptr+0(FP), A0
+ MOVW val+8(FP), A1
+ AMOANDW A1, (A0), ZERO
+ RET
+
+// func Or(ptr *uint32, val uint32)
+TEXT ·Or(SB), NOSPLIT, $0-12
+ MOV ptr+0(FP), A0
+ MOVW val+8(FP), A1
+ AMOORW A1, (A0), ZERO
+ RET
+
+// func Or32(ptr *uint32, val uint32) uint32
+TEXT ·Or32(SB), NOSPLIT, $0-20
+ MOV ptr+0(FP), A0
+ MOVW val+8(FP), A1
+ AMOORW A1, (A0), A2
+ MOVW A2, ret+16(FP)
+ RET
+
+// func And32(ptr *uint32, val uint32) uint32
+TEXT ·And32(SB), NOSPLIT, $0-20
+ MOV ptr+0(FP), A0
+ MOVW val+8(FP), A1
+ AMOANDW A1, (A0), A2
+ MOVW A2, ret+16(FP)
+ RET
+
+// func Or64(ptr *uint64, val uint64) uint64
+TEXT ·Or64(SB), NOSPLIT, $0-24
+ MOV ptr+0(FP), A0
+ MOV val+8(FP), A1
+ AMOORD A1, (A0), A2
+ MOV A2, ret+16(FP)
+ RET
+
+// func And64(ptr *uint64, val uint64) uint64
+TEXT ·And64(SB), NOSPLIT, $0-24
+ MOV ptr+0(FP), A0
+ MOV val+8(FP), A1
+ AMOANDD A1, (A0), A2
+ MOV A2, ret+16(FP)
+ RET
+
+// func Anduintptr(ptr *uintptr, val uintptr) uintptr
+TEXT ·Anduintptr(SB), NOSPLIT, $0-24
+ JMP ·And64(SB)
+
+// func Oruintptr(ptr *uintptr, val uintptr) uintptr
+TEXT ·Oruintptr(SB), NOSPLIT, $0-24
+ JMP ·Or64(SB)