Add (incomplete) x86-64 mp_mulop variant

2 files changed, 95 insertions, 0 deletions

diff --git a/modules/mp_amd64/modinfo.txt b/modules/mp_amd64/modinfo.txt
index 8e6b72d20..4401c746d 100644
--- a/modules/mp_amd64/modinfo.txt
+++ b/modules/mp_amd64/modinfo.txt
@@ -8,6 +8,7 @@ load_on asm_ok
 bswap.h
 mp_asm.h
 mp_asmi.h
+#mp_mulop.cpp
 </replace>
 
 <arch>
diff --git a/modules/mp_amd64/mp_mulop.cpp b/modules/mp_amd64/mp_mulop.cpp
new file mode 100644
index 000000000..d1aa51489
--- /dev/null
+++ b/modules/mp_amd64/mp_mulop.cpp
@@ -0,0 +1,94 @@
+/*************************************************
+* 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;
+      }
+   }
+
+}
+
+}