diff options
Diffstat (limited to 'botan/src/math/bigint/mulop_generic/mp_mulop.cpp')
-rw-r--r-- | botan/src/math/bigint/mulop_generic/mp_mulop.cpp | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/botan/src/math/bigint/mulop_generic/mp_mulop.cpp b/botan/src/math/bigint/mulop_generic/mp_mulop.cpp new file mode 100644 index 0000000..4647d00 --- /dev/null +++ b/botan/src/math/bigint/mulop_generic/mp_mulop.cpp @@ -0,0 +1,77 @@ +/* +* Simple O(N^2) Multiplication and Squaring +* (C) 1999-2008 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#include <botan/mp_asm.h> +#include <botan/mp_asmi.h> +#include <botan/mp_core.h> +#include <botan/mem_ops.h> + +namespace Botan { + +extern "C" { + +/* +* Simple O(N^2) Multiplication +*/ +void bigint_simple_mul(word z[], const word x[], u32bit x_size, + const word y[], u32bit y_size) + { + const u32bit x_size_8 = x_size - (x_size % 8); + + clear_mem(z, x_size + y_size); + + for(u32bit i = 0; i != y_size; ++i) + { + const word y_i = y[i]; + + word carry = 0; + + for(u32bit j = 0; j != x_size_8; j += 8) + carry = word8_madd3(z + i + j, x + j, y_i, carry); + + for(u32bit j = x_size_8; j != x_size; ++j) + z[i+j] = word_madd3(x[j], y_i, z[i+j], &carry); + + z[x_size+i] = carry; + } + } + +/* +* Simple O(N^2) Squaring + +This is exactly the same algorithm as bigint_simple_mul, +however because C/C++ compilers suck at alias analysis it +is good to have the version where the compiler knows +that x == y + +There is an O(n^1.5) squaring algorithm specified in Handbook of +Applied Cryptography, chapter 14 +*/ +void bigint_simple_sqr(word z[], const word x[], u32bit x_size) + { + const u32bit x_size_8 = x_size - (x_size % 8); + + clear_mem(z, 2*x_size); + + for(u32bit i = 0; i != x_size; ++i) + { + const word x_i = x[i]; + word carry = 0; + + for(u32bit j = 0; j != x_size_8; j += 8) + carry = word8_madd3(z + i + j, x + j, x_i, carry); + + for(u32bit j = x_size_8; j != x_size; ++j) + z[i+j] = word_madd3(x[j], x_i, z[i+j], &carry); + + z[x_size+i] = carry; + } + } + +} + +} |