Make config.h more Autoconf friendly (GH #835, PR #836)

1 files changed, 14 insertions, 0 deletions

diff --git a/rw.cpp b/rw.cpp
index d7287fad..ab79358c 100644
--- a/rw.cpp
+++ b/rw.cpp
@@ -126,6 +126,8 @@ void InvertibleRWFunction::PrecomputeTweakedRoots() const
 {

 	ModularArithmetic modp(m_p), modq(m_q);

 

+	// GCC warning bug, https://stackoverflow.com/q/12842306/608639

+#ifdef _OPENMP

 	#pragma omp parallel sections if(CRYPTOPP_RW_USE_OMP)

 	{

 		#pragma omp section

@@ -135,6 +137,11 @@ void InvertibleRWFunction::PrecomputeTweakedRoots() const
 		#pragma omp section

 			m_pre_q_p = modp.Exponentiate(m_q, m_p - 2);

 	}

+#else

+	m_pre_2_9p = modp.Exponentiate(2, (9 * m_p - 11)/8);

+	m_pre_2_3q = modq.Exponentiate(2, (3 * m_q - 5)/8);

+	m_pre_q_p = modp.Exponentiate(m_q, m_p - 2);

+#endif

 

 	m_precompute = true;

 }

@@ -223,6 +230,7 @@ Integer InvertibleRWFunction::CalculateInverse(RandomNumberGenerator &rng, const
 	else

 		f = 2;

 

+#ifdef _OPENMP

 	Integer W, X;

 	#pragma omp parallel sections if(CRYPTOPP_RW_USE_OMP)

 	{

@@ -236,6 +244,12 @@ Integer InvertibleRWFunction::CalculateInverse(RandomNumberGenerator &rng, const
 			X = (f.IsUnit() ? t : modp.Multiply(m_pre_2_9p, t));

 		}

 	}

+#else

+	const Integer W = (f.IsUnit() ? U : modq.Multiply(m_pre_2_3q, U));

+	const Integer t = modp.Multiply(modp.Exponentiate(V, 3), eh);

+	const Integer X = (f.IsUnit() ? t : modp.Multiply(m_pre_2_9p, t));

+#endif

+

 	const Integer Y = W + q * modp.Multiply(m_pre_q_p, (X - W));

 

 	// Signature