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authorgVisor bot <gvisor-bot@google.com>2019-10-03 16:13:34 -0700
committergVisor bot <gvisor-bot@google.com>2019-10-03 16:13:34 -0700
commit135aadb5179c94972504910e66e9e2540c09d489 (patch)
treea20d326ac8629e96cc1270aca6f6013d6d7c20f3
parentdb218fdfcf16b664c990f02c94ed89ac2c1ad314 (diff)
parenta26276b9498843218ee78c956c478ceebb819ad8 (diff)
Merge pull request #757 from xiaobo55x:pkg_bits
PiperOrigin-RevId: 272760964
-rw-r--r--pkg/bits/BUILD3
-rw-r--r--pkg/bits/uint64_arch.go (renamed from pkg/bits/uint64_arch_amd64.go)2
-rw-r--r--pkg/bits/uint64_arch_arm64_asm.s33
-rw-r--r--pkg/bits/uint64_arch_generic.go2
4 files changed, 37 insertions, 3 deletions
diff --git a/pkg/bits/BUILD b/pkg/bits/BUILD
index 51967b811..1b5dac99a 100644
--- a/pkg/bits/BUILD
+++ b/pkg/bits/BUILD
@@ -11,8 +11,9 @@ go_library(
"bits.go",
"bits32.go",
"bits64.go",
- "uint64_arch_amd64.go",
+ "uint64_arch.go",
"uint64_arch_amd64_asm.s",
+ "uint64_arch_arm64_asm.s",
"uint64_arch_generic.go",
],
importpath = "gvisor.dev/gvisor/pkg/bits",
diff --git a/pkg/bits/uint64_arch_amd64.go b/pkg/bits/uint64_arch.go
index faccaa61a..9f23eff77 100644
--- a/pkg/bits/uint64_arch_amd64.go
+++ b/pkg/bits/uint64_arch.go
@@ -12,7 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.
-// +build amd64
+// +build amd64 arm64
package bits
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
diff --git a/pkg/bits/uint64_arch_generic.go b/pkg/bits/uint64_arch_generic.go
index 7dd2d1480..9dd2098d1 100644
--- a/pkg/bits/uint64_arch_generic.go
+++ b/pkg/bits/uint64_arch_generic.go
@@ -12,7 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.
-// +build !amd64
+// +build !amd64,!arm64
package bits