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-rw-r--r--src/asm/mp_amd64/mp_mulop.cpp94
1 files changed, 94 insertions, 0 deletions
diff --git a/src/asm/mp_amd64/mp_mulop.cpp b/src/asm/mp_amd64/mp_mulop.cpp
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+++ b/src/asm/mp_amd64/mp_mulop.cpp
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+/*************************************************
+* Simple O(N^2) Multiplication and Squaring *
+* (C) 1999-2008 Jack Lloyd *
+*************************************************/
+
+#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 blocks = x_size - (x_size % 8);
+
+ clear_mem(z, x_size + y_size);
+
+ for(u32bit i = 0; i != y_size; ++i)
+ {
+ word carry = 0;
+
+ for(u32bit j = 0; j != blocks; j += 8)
+ carry = word8_madd3(z + i + j, x + j, y[i], carry);
+
+ for(u32bit j = blocks; j != x_size; ++j)
+ z[i+j] = word_madd3(x[j], y[i], z[i+j], &carry);
+
+ z[x_size+i] = carry;
+ }
+ }
+
+inline word word_sqr(word x,
+
+/*************************************************
+* 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
+*************************************************/
+void bigint_simple_sqr(word z[], const word x[], u32bit x_size)
+ {
+ clear_mem(z, 2*x_size);
+
+ for(u32bit i = 0; i != x_size; ++i)
+ {
+ const word x_i = x[i];
+
+ word carry = z[2*i];
+ z[2*i] = word_madd2(x_i, x_i, z[2*i], &carry);
+
+ for(u32bit j = i; j != x_size; ++j)
+ {
+ // z[i+j] = z[i+j] + 2 * x[j] * x_i + carry;
+
+ /*
+ load z[i+j] into register
+ load x[j] into %hi
+ mulq %[x_i] -> x[i] * x[j] -> %lo:%hi
+ shlq %lo, $1
+
+ // put carry bit (cf) from %lo into %temp
+ xorl %temp
+ adcq $0, %temp
+
+ // high bit of lo now in cf
+ shl %hi, $1
+ // add in lowest bid from %lo
+ orl %temp, %hi
+
+ addq %[c], %[lo]
+ adcq $0, %[hi]
+ addq %[z_ij], %[lo]
+ adcq $0, %[hi]
+
+ */
+
+ }
+
+ z[x_size+i] = carry;
+ }
+ }
+
+}
+
+}