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-rw-r--r--src/runtime/internal/math/math.go19
1 files changed, 19 insertions, 0 deletions
diff --git a/src/runtime/internal/math/math.go b/src/runtime/internal/math/math.go
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+++ b/src/runtime/internal/math/math.go
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+// Copyright 2018 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.
+
+package math
+
+import "runtime/internal/sys"
+
+const MaxUintptr = ^uintptr(0)
+
+// MulUintptr returns a * b and whether the multiplication overflowed.
+// On supported platforms this is an intrinsic lowered by the compiler.
+func MulUintptr(a, b uintptr) (uintptr, bool) {
+ if a|b < 1<<(4*sys.PtrSize) || a == 0 {
+ return a * b, false
+ }
+ overflow := b > MaxUintptr/a
+ return a * b, overflow
+}