From 906eb6295d54a05663a223f1dc379a16148de2d1 Mon Sep 17 00:00:00 2001
From: gVisor bot <gvisor-bot@google.com>
Date: Tue, 18 Feb 2020 13:42:31 -0800
Subject: atomicbitops package cleanups

- Redocument memory ordering from "no ordering" to "acquire-release". (No
  functional change: both LOCK WHATEVER on x86, and LDAXR/STLXR loops on ARM64,
  already have this property.)

- Remove IncUnlessZeroInt32 and DecUnlessOneInt32, which were only faster than
  the equivalent loops using sync/atomic before the Go compiler inlined
  non-unsafe.Pointer atomics many releases ago.

PiperOrigin-RevId: 295811743
---
 pkg/atomicbitops/atomic_bitops_arm64.s | 139 ---------------------------------
 1 file changed, 139 deletions(-)
 delete mode 100644 pkg/atomicbitops/atomic_bitops_arm64.s

(limited to 'pkg/atomicbitops/atomic_bitops_arm64.s')

diff --git a/pkg/atomicbitops/atomic_bitops_arm64.s b/pkg/atomicbitops/atomic_bitops_arm64.s
deleted file mode 100644
index 97f8808c1..000000000
--- a/pkg/atomicbitops/atomic_bitops_arm64.s
+++ /dev/null
@@ -1,139 +0,0 @@
-// Copyright 2019 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// +build arm64
-
-#include "textflag.h"
-
-TEXT ·AndUint32(SB),$0-12
-  MOVD    ptr+0(FP), R0
-  MOVW    val+8(FP), R1
-again:
-  LDAXRW  (R0), R2
-  ANDW    R1, R2
-  STLXRW  R2, (R0), R3
-  CBNZ    R3, again
-  RET
-
-TEXT ·OrUint32(SB),$0-12
-  MOVD    ptr+0(FP), R0
-  MOVW    val+8(FP), R1
-again:
-  LDAXRW  (R0), R2
-  ORRW    R1, R2
-  STLXRW  R2, (R0), R3
-  CBNZ    R3, again
-  RET
-
-TEXT ·XorUint32(SB),$0-12
-  MOVD    ptr+0(FP), R0
-  MOVW    val+8(FP), R1
-again:
-  LDAXRW  (R0), R2
-  EORW    R1, R2
-  STLXRW  R2, (R0), R3
-  CBNZ    R3, again
-  RET
-
-TEXT ·CompareAndSwapUint32(SB),$0-20
-  MOVD addr+0(FP), R0
-  MOVW old+8(FP), R1
-  MOVW new+12(FP), R2
-
-again:
-  LDAXRW (R0), R3
-  CMPW R1, R3
-  BNE done
-  STLXRW R2, (R0), R4
-  CBNZ R4, again
-done:
-  MOVW R3, prev+16(FP)
-  RET
-
-TEXT ·AndUint64(SB),$0-16
-  MOVD    ptr+0(FP), R0
-  MOVD    val+8(FP), R1
-again:
-  LDAXR   (R0), R2
-  AND     R1, R2
-  STLXR   R2, (R0), R3
-  CBNZ    R3, again
-  RET
-
-TEXT ·OrUint64(SB),$0-16
-  MOVD    ptr+0(FP), R0
-  MOVD    val+8(FP), R1
-again:
-  LDAXR   (R0), R2
-  ORR     R1, R2
-  STLXR   R2, (R0), R3
-  CBNZ    R3, again
-  RET
-
-TEXT ·XorUint64(SB),$0-16
-  MOVD    ptr+0(FP), R0
-  MOVD    val+8(FP), R1
-again:
-  LDAXR   (R0), R2
-  EOR     R1, R2
-  STLXR   R2, (R0), R3
-  CBNZ    R3, again
-  RET
-
-TEXT ·CompareAndSwapUint64(SB),$0-32
-  MOVD addr+0(FP), R0
-  MOVD old+8(FP), R1
-  MOVD new+16(FP), R2
-
-again:
-  LDAXR (R0), R3
-  CMP R1, R3
-  BNE done
-  STLXR R2, (R0), R4
-  CBNZ R4, again
-done:
-  MOVD R3, prev+24(FP)
-  RET
-
-TEXT ·IncUnlessZeroInt32(SB),NOSPLIT,$0-9
-  MOVD addr+0(FP), R0
-
-again:
-  LDAXRW (R0), R1
-  CBZ R1, fail
-  ADDW $1, R1
-  STLXRW R1, (R0), R2
-  CBNZ R2, again
-  MOVW $1, R2
-  MOVB R2, ret+8(FP)
-  RET
-fail:
-  MOVB ZR, ret+8(FP)
-  RET
-
-TEXT ·DecUnlessOneInt32(SB),NOSPLIT,$0-9
-  MOVD addr+0(FP), R0
-
-again:
-  LDAXRW (R0), R1
-  SUBSW $1, R1, R1
-  BEQ fail
-  STLXRW R1, (R0), R2
-  CBNZ R2, again
-  MOVW $1, R2
-  MOVB R2, ret+8(FP)
-  RET
-fail:
-  MOVB ZR, ret+8(FP)
-  RET
-- 
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