Use IsPowerOf2 in Integer::Divide

1 files changed, 3 insertions, 1 deletions

diff --git a/integer.cpp b/integer.cpp
index 1771b429..78dd10a1 100644
--- a/integer.cpp
+++ b/integer.cpp
@@ -4244,7 +4244,9 @@ void Integer::Divide(word &remainder, Integer &quotient, const Integer &dividend
 	if (!divisor)

 		throw Integer::DivideByZero();

 

-	if ((divisor & (divisor-1)) == 0)	// divisor is a power of 2

+	// IsPowerOf2 uses BMI on x86 if available. There is a small

+	// but measurable improvement during decryption and signing.

+	if (IsPowerOf2(divisor))

 	{

 		quotient = dividend >> (BitPrecision(divisor)-1);

 		remainder = dividend.reg[0] & (divisor-1);