Merge pull request #4007 from randombit/jack/comba-fn-call-unrolled

Redirect from the template Comba to the unrolled Combas where possible
randombit · Apr 12, 2024 · d184e78 · d184e78
2 parents c428cbc + 4f574d2
commit d184e78
Showing 1 changed file with 53 additions and 17 deletions.
diff --git a/src/lib/math/mp/mp_core.h b/src/lib/math/mp/mp_core.h
@@ -890,11 +890,46 @@ consteval auto hex_to_words(const char (&s)[N]) {
    return r;
 }
 
+/*
+* Comba Multiplication / Squaring
+*/
+BOTAN_FUZZER_API void bigint_comba_mul4(word z[8], const word x[4], const word y[4]);
+BOTAN_FUZZER_API void bigint_comba_mul6(word z[12], const word x[6], const word y[6]);
+BOTAN_FUZZER_API void bigint_comba_mul8(word z[16], const word x[8], const word y[8]);
+BOTAN_FUZZER_API void bigint_comba_mul9(word z[18], const word x[9], const word y[9]);
+BOTAN_FUZZER_API void bigint_comba_mul16(word z[32], const word x[16], const word y[16]);
+BOTAN_FUZZER_API void bigint_comba_mul24(word z[48], const word x[24], const word y[24]);
+
+BOTAN_FUZZER_API void bigint_comba_sqr4(word out[8], const word in[4]);
+BOTAN_FUZZER_API void bigint_comba_sqr6(word out[12], const word in[6]);
+BOTAN_FUZZER_API void bigint_comba_sqr8(word out[16], const word in[8]);
+BOTAN_FUZZER_API void bigint_comba_sqr9(word out[18], const word in[9]);
+BOTAN_FUZZER_API void bigint_comba_sqr16(word out[32], const word in[16]);
+BOTAN_FUZZER_API void bigint_comba_sqr24(word out[48], const word in[24]);
+
 /*
 * Comba Fixed Length Multiplication
 */
 template <size_t N, WordType W>
 constexpr inline void comba_mul(W z[2 * N], const W x[N], const W y[N]) {
+   if(!std::is_constant_evaluated()) {
+      if constexpr(std::same_as<W, word> && N == 4) {
+         return bigint_comba_mul4(z, x, y);
+      }
+      if constexpr(std::same_as<W, word> && N == 6) {
+         return bigint_comba_mul6(z, x, y);
+      }
+      if constexpr(std::same_as<W, word> && N == 8) {
+         return bigint_comba_mul8(z, x, y);
+      }
+      if constexpr(std::same_as<W, word> && N == 9) {
+         return bigint_comba_mul9(z, x, y);
+      }
+      if constexpr(std::same_as<W, word> && N == 16) {
+         return bigint_comba_mul16(z, x, y);
+      }
+   }
+
    word3<W> accum;
 
    for(size_t i = 0; i != 2 * N; ++i) {
@@ -910,6 +945,24 @@ constexpr inline void comba_mul(W z[2 * N], const W x[N], const W y[N]) {
 
 template <size_t N, WordType W>
 constexpr inline void comba_sqr(W z[2 * N], const W x[N]) {
+   if(!std::is_constant_evaluated()) {
+      if constexpr(std::same_as<W, word> && N == 4) {
+         return bigint_comba_sqr4(z, x);
+      }
+      if constexpr(std::same_as<W, word> && N == 6) {
+         return bigint_comba_sqr6(z, x);
+      }
+      if constexpr(std::same_as<W, word> && N == 8) {
+         return bigint_comba_sqr8(z, x);
+      }
+      if constexpr(std::same_as<W, word> && N == 9) {
+         return bigint_comba_sqr9(z, x);
+      }
+      if constexpr(std::same_as<W, word> && N == 16) {
+         return bigint_comba_sqr16(z, x);
+      }
+   }
+
    word3<W> accum;
 
    for(size_t i = 0; i != 2 * N; ++i) {
@@ -923,23 +976,6 @@ constexpr inline void comba_sqr(W z[2 * N], const W x[N]) {
    }
 }
 
-/*
-* Comba Multiplication / Squaring
-*/
-BOTAN_FUZZER_API void bigint_comba_mul4(word z[8], const word x[4], const word y[4]);
-BOTAN_FUZZER_API void bigint_comba_mul6(word z[12], const word x[6], const word y[6]);
-BOTAN_FUZZER_API void bigint_comba_mul8(word z[16], const word x[8], const word y[8]);
-BOTAN_FUZZER_API void bigint_comba_mul9(word z[18], const word x[9], const word y[9]);
-BOTAN_FUZZER_API void bigint_comba_mul16(word z[32], const word x[16], const word y[16]);
-BOTAN_FUZZER_API void bigint_comba_mul24(word z[48], const word x[24], const word y[24]);
-
-BOTAN_FUZZER_API void bigint_comba_sqr4(word out[8], const word in[4]);
-BOTAN_FUZZER_API void bigint_comba_sqr6(word out[12], const word in[6]);
-BOTAN_FUZZER_API void bigint_comba_sqr8(word out[16], const word in[8]);
-BOTAN_FUZZER_API void bigint_comba_sqr9(word out[18], const word in[9]);
-BOTAN_FUZZER_API void bigint_comba_sqr16(word out[32], const word in[16]);
-BOTAN_FUZZER_API void bigint_comba_sqr24(word out[48], const word in[24]);
-
 /*
 * Montgomery reduction
 *