math/bits: add examples for right rotation

Right rotation is achieved using negative k in RotateLeft*(x, k). Add
examples demonstrating that functionality.

Change-Id: I15dab159accd2937cb18d3fa8ca32da8501567d3
Reviewed-on: https://go-review.googlesource.com/75371
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/math/bits/example_test.go b/src/math/bits/example_test.go
index dd400da0fe..18e026b9b4 100644
--- a/src/math/bits/example_test.go
+++ b/src/math/bits/example_test.go
@@ -86,33 +86,41 @@ func ExampleOnesCount64() {
 func ExampleRotateLeft8() {
 	fmt.Printf("%08b\n", 15)
 	fmt.Printf("%08b\n", bits.RotateLeft8(15, 2))
+	fmt.Printf("%08b\n", bits.RotateLeft8(15, -2))
 	// Output:
 	// 00001111
 	// 00111100
+	// 11000011
 }
 
 func ExampleRotateLeft16() {
 	fmt.Printf("%016b\n", 15)
 	fmt.Printf("%016b\n", bits.RotateLeft16(15, 2))
+	fmt.Printf("%016b\n", bits.RotateLeft16(15, -2))
 	// Output:
 	// 0000000000001111
 	// 0000000000111100
+	// 1100000000000011
 }
 
 func ExampleRotateLeft32() {
 	fmt.Printf("%032b\n", 15)
 	fmt.Printf("%032b\n", bits.RotateLeft32(15, 2))
+	fmt.Printf("%032b\n", bits.RotateLeft32(15, -2))
 	// Output:
 	// 00000000000000000000000000001111
 	// 00000000000000000000000000111100
+	// 11000000000000000000000000000011
 }
 
 func ExampleRotateLeft64() {
 	fmt.Printf("%064b\n", 15)
 	fmt.Printf("%064b\n", bits.RotateLeft64(15, 2))
+	fmt.Printf("%064b\n", bits.RotateLeft64(15, -2))
 	// Output:
 	// 0000000000000000000000000000000000000000000000000000000000001111
 	// 0000000000000000000000000000000000000000000000000000000000111100
+	// 1100000000000000000000000000000000000000000000000000000000000011
 }
 
 func ExampleReverse8() {