math/big: fix Int.Exp
Fixes #7814.
LGTM=agl, adonovan
R=agl, adonovan
CC=golang-codereviews
https://golang.org/cl/90080043
diff --git a/src/pkg/math/big/nat.go b/src/pkg/math/big/nat.go
index 6874900..16a87f5 100644
--- a/src/pkg/math/big/nat.go
+++ b/src/pkg/math/big/nat.go
@@ -1233,10 +1233,15 @@
z = nil
}
+ // x**y mod 1 == 0
+ if len(m) == 1 && m[0] == 1 {
+ return z.setWord(0)
+ }
+ // m == 0 || m > 1
+
+ // x**0 == 1
if len(y) == 0 {
- z = z.make(1)
- z[0] = 1
- return z
+ return z.setWord(1)
}
// y > 0
