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| author | gVisor bot <gvisor-bot@google.com> | 2019-10-03 16:13:34 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2019-10-03 16:13:34 -0700 |
| commit | 135aadb5179c94972504910e66e9e2540c09d489 (patch) | |
| tree | a20d326ac8629e96cc1270aca6f6013d6d7c20f3 /pkg/bits/uint64_arch_arm64_asm.s | |
| parent | db218fdfcf16b664c990f02c94ed89ac2c1ad314 (diff) | |
| parent | a26276b9498843218ee78c956c478ceebb819ad8 (diff) | |
Merge pull request #757 from xiaobo55x:pkg_bits
PiperOrigin-RevId: 272760964
Diffstat (limited to 'pkg/bits/uint64_arch_arm64_asm.s')
| -rw-r--r-- | pkg/bits/uint64_arch_arm64_asm.s | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/pkg/bits/uint64_arch_arm64_asm.s b/pkg/bits/uint64_arch_arm64_asm.s new file mode 100644 index 000000000..814ba562d --- /dev/null +++ b/pkg/bits/uint64_arch_arm64_asm.s @@ -0,0 +1,33 @@ +// 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 + +TEXT ·TrailingZeros64(SB),$0-16 + MOVD x+0(FP), R0 + RBIT R0, R0 + CLZ R0, R0 // return 64 if x == 0 + MOVD R0, ret+8(FP) + RET + +TEXT ·MostSignificantOne64(SB),$0-16 + MOVD x+0(FP), R0 + CLZ R0, R0 // return 64 if x == 0 + MOVD $63, R1 + SUBS R0, R1, R0 // ret = 63 - CLZ + BPL end + MOVD $64, R0 // x == 0 +end: + MOVD R0, ret+8(FP) + RET |