q15

1 files changed, 5 insertions, 0 deletions

diff --git a/docs/q15 b/docs/q15
index 9211a4ae..26ea7d71 100644
--- a/docs/q15
+++ b/docs/q15
@@ -28,3 +28,8 @@ This is a very accurate way to convert un8 into this format:
 	 // add (a, 0xffff)
 	 // xor (a, 0xffff)
      }
+
+Here is another very accurate way:
+
+     return mulhrsw (a << 7, 0x807f) - a;
+