Remove BigInt using functions from mp layer

2 files changed, 20 insertions, 7 deletions

diff --git a/src/lib/math/numbertheory/monty.cpp b/src/lib/math/numbertheory/monty.cpp
index 64646a61a..76575a88c 100644
--- a/src/lib/math/numbertheory/monty.cpp
+++ b/src/lib/math/numbertheory/monty.cpp
@@ -52,9 +52,15 @@ BigInt Montgomery_Params::mul(const BigInt& x, const BigInt& y) const
    const size_t output_size = 2*m_p_words + 2;
    std::vector<word> ws(output_size);
    BigInt z(BigInt::Positive, output_size);
-   bigint_monty_mul(z, x, y,
-                    m_p.data(), m_p_words, m_p_dash,
-                    ws.data(), ws.size());
+   bigint_mul(z.mutable_data(), z.size(),
+              x.data(), x.size(), x.sig_words(),
+              y.data(), y.size(), y.sig_words(),
+              ws.data(), ws.size());
+
+   bigint_monty_redc(z.mutable_data(),
+                     m_p.data(), m_p_words, m_p_dash,
+                     ws.data(), ws.size());
+
    secure_scrub_memory(ws.data(), ws.size() * sizeof(word));
    return z;
    }
diff --git a/src/lib/math/numbertheory/mp_numth.cpp b/src/lib/math/numbertheory/mp_numth.cpp
index c39c40520..5ad72cd47 100644
--- a/src/lib/math/numbertheory/mp_numth.cpp
+++ b/src/lib/math/numbertheory/mp_numth.cpp
@@ -41,13 +41,20 @@ BigInt mul_add(const BigInt& a, const BigInt& b, const BigInt& c)
    if(a.sign() != b.sign())
       sign = BigInt::Negative;
 
-   BigInt r(sign, std::max(a.size() + b.size(), c.sig_words()) + 1);
+   const size_t a_sw = a.sig_words();
+   const size_t b_sw = b.sig_words();
+   const size_t c_sw = c.sig_words();
+
+   BigInt r(sign, std::max(a_sw + b_sw, c_sw) + 1);
    secure_vector<word> workspace(r.size());
 
-   bigint_mul(r, a, b, workspace.data(), workspace.size());
+   bigint_mul(r.mutable_data(), r.size(),
+              a.data(), a.size(), a_sw,
+              b.data(), b.size(), b_sw,
+              workspace.data(), workspace.size());
 
-   const size_t r_size = std::max(r.sig_words(), c.sig_words());
-   bigint_add2(r.mutable_data(), r_size, c.data(), c.sig_words());
+   const size_t r_size = std::max(r.sig_words(), c_sw);
+   bigint_add2(r.mutable_data(), r_size, c.data(), c_sw);
    return r;
    }