Change the NSS and NSPR source tree to the new directory structure to be

mozilla/security/nss/lib/freebl/mpi/mpmontg.c

Index: mozilla/security/nss/lib/freebl/mpi/mpmontg.c
===================================================================
--- mozilla/security/nss/lib/freebl/mpi/mpmontg.c	(revision 191424)
+++ mozilla/security/nss/lib/freebl/mpi/mpmontg.c	(working copy)
@@ -1,1174 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-/* $Id: mpmontg.c,v 1.25 2012/11/14 01:14:11 wtc%google.com Exp $ */
-
-/* This file implements moduluar exponentiation using Montgomery's
- * method for modular reduction.  This file implements the method
- * described as "Improvement 2" in the paper "A Cryptogrpahic Library for
- * the Motorola DSP56000" by Stephen R. Dusse' and Burton S. Kaliski Jr.
- * published in "Advances in Cryptology: Proceedings of EUROCRYPT '90"
- * "Lecture Notes in Computer Science" volume 473, 1991, pg 230-244,
- * published by Springer Verlag.
- */
-
-#define MP_USING_CACHE_SAFE_MOD_EXP 1 
-#include <string.h>
-#include "mpi-priv.h"
-#include "mplogic.h"
-#include "mpprime.h"
-#ifdef MP_USING_MONT_MULF
-#include "montmulf.h"
-#endif
-#include <stddef.h> /* ptrdiff_t */
-
-/* if MP_CHAR_STORE_SLOW is defined, we  */
-/* need to know endianness of this platform. */
-#ifdef MP_CHAR_STORE_SLOW
-#if !defined(MP_IS_BIG_ENDIAN) && !defined(MP_IS_LITTLE_ENDIAN)
-#error "You must define MP_IS_BIG_ENDIAN or MP_IS_LITTLE_ENDIAN\n" \
-       "  if you define MP_CHAR_STORE_SLOW."
-#endif
-#endif
-
-#define STATIC
-
-#define MAX_ODD_INTS    32   /* 2 ** (WINDOW_BITS - 1) */
-
-/*! computes T = REDC(T), 2^b == R 
-    \param T < RN
-*/
-mp_err s_mp_redc(mp_int *T, mp_mont_modulus *mmm)
-{
-  mp_err res;
-  mp_size i;
-
-  i = (MP_USED(&mmm->N) << 1) + 1;
-  MP_CHECKOK( s_mp_pad(T, i) );
-  for (i = 0; i < MP_USED(&mmm->N); ++i ) {
-    mp_digit m_i = MP_DIGIT(T, i) * mmm->n0prime;
-    /* T += N * m_i * (MP_RADIX ** i); */
-    MP_CHECKOK( s_mp_mul_d_add_offset(&mmm->N, m_i, T, i) );
-  }
-  s_mp_clamp(T);
-
-  /* T /= R */
-  s_mp_rshd( T, MP_USED(&mmm->N) );
-
-  if ((res = s_mp_cmp(T, &mmm->N)) >= 0) {
-    /* T = T - N */
-    MP_CHECKOK( s_mp_sub(T, &mmm->N) );
-#ifdef DEBUG
-    if ((res = mp_cmp(T, &mmm->N)) >= 0) {
-      res = MP_UNDEF;
-      goto CLEANUP;
-    }
-#endif
-  }
-  res = MP_OKAY;
-CLEANUP:
-  return res;
-}
-
-#if !defined(MP_MONT_USE_MP_MUL)
-
-/*! c <- REDC( a * b ) mod N
-    \param a < N  i.e. "reduced"
-    \param b < N  i.e. "reduced"
-    \param mmm modulus N and n0' of N
-*/
-mp_err s_mp_mul_mont(const mp_int *a, const mp_int *b, mp_int *c, 
-	           mp_mont_modulus *mmm)
-{
-  mp_digit *pb;
-  mp_digit m_i;
-  mp_err   res;
-  mp_size  ib; /* "index b": index of current digit of B */
-  mp_size  useda, usedb;
-
-  ARGCHK(a != NULL && b != NULL && c != NULL, MP_BADARG);
-
-  if (MP_USED(a) < MP_USED(b)) {
-    const mp_int *xch = b;	/* switch a and b, to do fewer outer loops */
-    b = a;
-    a = xch;
-  }
-
-  MP_USED(c) = 1; MP_DIGIT(c, 0) = 0;
-  ib = (MP_USED(&mmm->N) << 1) + 1;
-  if((res = s_mp_pad(c, ib)) != MP_OKAY)
-    goto CLEANUP;
-
-  useda = MP_USED(a);
-  pb = MP_DIGITS(b);
-  s_mpv_mul_d(MP_DIGITS(a), useda, *pb++, MP_DIGITS(c));
-  s_mp_setz(MP_DIGITS(c) + useda + 1, ib - (useda + 1));
-  m_i = MP_DIGIT(c, 0) * mmm->n0prime;
-  s_mp_mul_d_add_offset(&mmm->N, m_i, c, 0);
-
-  /* Outer loop:  Digits of b */
-  usedb = MP_USED(b);
-  for (ib = 1; ib < usedb; ib++) {
-    mp_digit b_i    = *pb++;
-
-    /* Inner product:  Digits of a */
-    if (b_i)
-      s_mpv_mul_d_add_prop(MP_DIGITS(a), useda, b_i, MP_DIGITS(c) + ib);
-    m_i = MP_DIGIT(c, ib) * mmm->n0prime;
-    s_mp_mul_d_add_offset(&mmm->N, m_i, c, ib);
-  }
-  if (usedb < MP_USED(&mmm->N)) {
-    for (usedb = MP_USED(&mmm->N); ib < usedb; ++ib ) {
-      m_i = MP_DIGIT(c, ib) * mmm->n0prime;
-      s_mp_mul_d_add_offset(&mmm->N, m_i, c, ib);
-    }
-  }
-  s_mp_clamp(c);
-  s_mp_rshd( c, MP_USED(&mmm->N) ); /* c /= R */
-  if (s_mp_cmp(c, &mmm->N) >= 0) {
-    MP_CHECKOK( s_mp_sub(c, &mmm->N) );
-  }
-  res = MP_OKAY;
-
-CLEANUP:
-  return res;
-}
-#endif
-
-STATIC
-mp_err s_mp_to_mont(const mp_int *x, mp_mont_modulus *mmm, mp_int *xMont)
-{
-  mp_err res;
-
-  /* xMont = x * R mod N   where  N is modulus */
-  MP_CHECKOK( mp_copy( x, xMont ) );
-  MP_CHECKOK( s_mp_lshd( xMont, MP_USED(&mmm->N) ) );	/* xMont = x << b */
-  MP_CHECKOK( mp_div(xMont, &mmm->N, 0, xMont) );	/*         mod N */
-CLEANUP:
-  return res;
-}
-
-#ifdef MP_USING_MONT_MULF
-
-/* the floating point multiply is already cache safe,
- * don't turn on cache safe unless we specifically
- * force it */
-#ifndef MP_FORCE_CACHE_SAFE
-#undef MP_USING_CACHE_SAFE_MOD_EXP
-#endif
-
-unsigned int mp_using_mont_mulf = 1;
-
-/* computes montgomery square of the integer in mResult */
-#define SQR \
-  conv_i32_to_d32_and_d16(dm1, d16Tmp, mResult, nLen); \
-  mont_mulf_noconv(mResult, dm1, d16Tmp, \
-		   dTmp, dn, MP_DIGITS(modulus), nLen, dn0)
-
-/* computes montgomery product of x and the integer in mResult */
-#define MUL(x) \
-  conv_i32_to_d32(dm1, mResult, nLen); \
-  mont_mulf_noconv(mResult, dm1, oddPowers[x], \
-		   dTmp, dn, MP_DIGITS(modulus), nLen, dn0)
-
-/* Do modular exponentiation using floating point multiply code. */
-mp_err mp_exptmod_f(const mp_int *   montBase, 
-                    const mp_int *   exponent, 
-		    const mp_int *   modulus, 
-		    mp_int *         result, 
-		    mp_mont_modulus *mmm, 
-		    int              nLen, 
-		    mp_size          bits_in_exponent, 
-		    mp_size          window_bits,
-		    mp_size          odd_ints)
-{
-  mp_digit *mResult;
-  double   *dBuf = 0, *dm1, *dn, *dSqr, *d16Tmp, *dTmp;
-  double    dn0;
-  mp_size   i;
-  mp_err    res;
-  int       expOff;
-  int       dSize = 0, oddPowSize, dTmpSize;
-  mp_int    accum1;
-  double   *oddPowers[MAX_ODD_INTS];
-
-  /* function for computing n0prime only works if n0 is odd */
-
-  MP_DIGITS(&accum1) = 0;
-
-  for (i = 0; i < MAX_ODD_INTS; ++i)
-    oddPowers[i] = 0;
-
-  MP_CHECKOK( mp_init_size(&accum1, 3 * nLen + 2) );
-
-  mp_set(&accum1, 1);
-  MP_CHECKOK( s_mp_to_mont(&accum1, mmm, &accum1) );
-  MP_CHECKOK( s_mp_pad(&accum1, nLen) );
-
-  oddPowSize = 2 * nLen + 1;
-  dTmpSize   = 2 * oddPowSize;
-  dSize = sizeof(double) * (nLen * 4 + 1 + 
-			    ((odd_ints + 1) * oddPowSize) + dTmpSize);
-  dBuf   = (double *)malloc(dSize);
-  dm1    = dBuf;		/* array of d32 */
-  dn     = dBuf   + nLen;	/* array of d32 */
-  dSqr   = dn     + nLen;    	/* array of d32 */
-  d16Tmp = dSqr   + nLen;	/* array of d16 */
-  dTmp   = d16Tmp + oddPowSize;
-
-  for (i = 0; i < odd_ints; ++i) {
-      oddPowers[i] = dTmp;
-      dTmp += oddPowSize;
-  }
-  mResult = (mp_digit *)(dTmp + dTmpSize);	/* size is nLen + 1 */
-
-  /* Make dn and dn0 */
-  conv_i32_to_d32(dn, MP_DIGITS(modulus), nLen);
-  dn0 = (double)(mmm->n0prime & 0xffff);
-
-  /* Make dSqr */
-  conv_i32_to_d32_and_d16(dm1, oddPowers[0], MP_DIGITS(montBase), nLen);
-  mont_mulf_noconv(mResult, dm1, oddPowers[0], 
-		   dTmp, dn, MP_DIGITS(modulus), nLen, dn0);
-  conv_i32_to_d32(dSqr, mResult, nLen);
-
-  for (i = 1; i < odd_ints; ++i) {
-    mont_mulf_noconv(mResult, dSqr, oddPowers[i - 1], 
-		     dTmp, dn, MP_DIGITS(modulus), nLen, dn0);
-    conv_i32_to_d16(oddPowers[i], mResult, nLen);
-  }
-
-  s_mp_copy(MP_DIGITS(&accum1), mResult, nLen); /* from, to, len */
-
-  for (expOff = bits_in_exponent - window_bits; expOff >= 0; expOff -= window_bits) {
-    mp_size smallExp;
-    MP_CHECKOK( mpl_get_bits(exponent, expOff, window_bits) );
-    smallExp = (mp_size)res;
-
-    if (window_bits == 1) {
-      if (!smallExp) {
-	SQR;
-      } else if (smallExp & 1) {
-	SQR; MUL(0); 
-      } else {
-	abort();
-      }
-    } else if (window_bits == 4) {
-      if (!smallExp) {
-	SQR; SQR; SQR; SQR;
-      } else if (smallExp & 1) {
-	SQR; SQR; SQR; SQR; MUL(smallExp/2); 
-      } else if (smallExp & 2) {
-	SQR; SQR; SQR; MUL(smallExp/4); SQR; 
-      } else if (smallExp & 4) {
-	SQR; SQR; MUL(smallExp/8); SQR; SQR; 
-      } else if (smallExp & 8) {
-	SQR; MUL(smallExp/16); SQR; SQR; SQR; 
-      } else {
-	abort();
-      }
-    } else if (window_bits == 5) {
-      if (!smallExp) {
-	SQR; SQR; SQR; SQR; SQR; 
-      } else if (smallExp & 1) {
-	SQR; SQR; SQR; SQR; SQR; MUL(smallExp/2);
-      } else if (smallExp & 2) {
-	SQR; SQR; SQR; SQR; MUL(smallExp/4); SQR;
-      } else if (smallExp & 4) {
-	SQR; SQR; SQR; MUL(smallExp/8); SQR; SQR;
-      } else if (smallExp & 8) {
-	SQR; SQR; MUL(smallExp/16); SQR; SQR; SQR;
-      } else if (smallExp & 0x10) {
-	SQR; MUL(smallExp/32); SQR; SQR; SQR; SQR;
-      } else {
-	abort();
-      }
-    } else if (window_bits == 6) {
-      if (!smallExp) {
-	SQR; SQR; SQR; SQR; SQR; SQR;
-      } else if (smallExp & 1) {
-	SQR; SQR; SQR; SQR; SQR; SQR; MUL(smallExp/2); 
-      } else if (smallExp & 2) {
-	SQR; SQR; SQR; SQR; SQR; MUL(smallExp/4); SQR; 
-      } else if (smallExp & 4) {
-	SQR; SQR; SQR; SQR; MUL(smallExp/8); SQR; SQR; 
-      } else if (smallExp & 8) {
-	SQR; SQR; SQR; MUL(smallExp/16); SQR; SQR; SQR; 
-      } else if (smallExp & 0x10) {
-	SQR; SQR; MUL(smallExp/32); SQR; SQR; SQR; SQR; 
-      } else if (smallExp & 0x20) {
-	SQR; MUL(smallExp/64); SQR; SQR; SQR; SQR; SQR; 
-      } else {
-	abort();
-      }
-    } else {
-      abort();
-    }
-  }
-
-  s_mp_copy(mResult, MP_DIGITS(&accum1), nLen); /* from, to, len */
-
-  res = s_mp_redc(&accum1, mmm);
-  mp_exch(&accum1, result);
-
-CLEANUP:
-  mp_clear(&accum1);
-  if (dBuf) {
-    if (dSize)
-      memset(dBuf, 0, dSize);
-    free(dBuf);
-  }
-
-  return res;
-}
-#undef SQR
-#undef MUL
-#endif
-
-#define SQR(a,b) \
-  MP_CHECKOK( mp_sqr(a, b) );\
-  MP_CHECKOK( s_mp_redc(b, mmm) )
-
-#if defined(MP_MONT_USE_MP_MUL)
-#define MUL(x,a,b) \
-  MP_CHECKOK( mp_mul(a, oddPowers + (x), b) ); \
-  MP_CHECKOK( s_mp_redc(b, mmm) ) 
-#else
-#define MUL(x,a,b) \
-  MP_CHECKOK( s_mp_mul_mont(a, oddPowers + (x), b, mmm) )
-#endif
-
-#define SWAPPA ptmp = pa1; pa1 = pa2; pa2 = ptmp
-
-/* Do modular exponentiation using integer multiply code. */
-mp_err mp_exptmod_i(const mp_int *   montBase, 
-                    const mp_int *   exponent, 
-		    const mp_int *   modulus, 
-		    mp_int *         result, 
-		    mp_mont_modulus *mmm, 
-		    int              nLen, 
-		    mp_size          bits_in_exponent, 
-		    mp_size          window_bits,
-		    mp_size          odd_ints)
-{
-  mp_int *pa1, *pa2, *ptmp;
-  mp_size i;
-  mp_err  res;
-  int     expOff;
-  mp_int  accum1, accum2, power2, oddPowers[MAX_ODD_INTS];
-
-  /* power2 = base ** 2; oddPowers[i] = base ** (2*i + 1); */
-  /* oddPowers[i] = base ** (2*i + 1); */
-
-  MP_DIGITS(&accum1) = 0;
-  MP_DIGITS(&accum2) = 0;
-  MP_DIGITS(&power2) = 0;
-  for (i = 0; i < MAX_ODD_INTS; ++i) {
-    MP_DIGITS(oddPowers + i) = 0;
-  }
-
-  MP_CHECKOK( mp_init_size(&accum1, 3 * nLen + 2) );
-  MP_CHECKOK( mp_init_size(&accum2, 3 * nLen + 2) );
-
-  MP_CHECKOK( mp_init_copy(&oddPowers[0], montBase) );
-
-  mp_init_size(&power2, nLen + 2 * MP_USED(montBase) + 2);
-  MP_CHECKOK( mp_sqr(montBase, &power2) );	/* power2 = montBase ** 2 */
-  MP_CHECKOK( s_mp_redc(&power2, mmm) );
-
-  for (i = 1; i < odd_ints; ++i) {
-    mp_init_size(oddPowers + i, nLen + 2 * MP_USED(&power2) + 2);
-    MP_CHECKOK( mp_mul(oddPowers + (i - 1), &power2, oddPowers + i) );
-    MP_CHECKOK( s_mp_redc(oddPowers + i, mmm) );
-  }
-
-  /* set accumulator to montgomery residue of 1 */
-  mp_set(&accum1, 1);
-  MP_CHECKOK( s_mp_to_mont(&accum1, mmm, &accum1) );
-  pa1 = &accum1;
-  pa2 = &accum2;
-
-  for (expOff = bits_in_exponent - window_bits; expOff >= 0; expOff -= window_bits) {
-    mp_size smallExp;
-    MP_CHECKOK( mpl_get_bits(exponent, expOff, window_bits) );
-    smallExp = (mp_size)res;
-
-    if (window_bits == 1) {
-      if (!smallExp) {
-	SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 1) {
-	SQR(pa1,pa2); MUL(0,pa2,pa1);
-      } else {
-	abort();
-      }
-    } else if (window_bits == 4) {
-      if (!smallExp) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
-      } else if (smallExp & 1) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	MUL(smallExp/2, pa1,pa2); SWAPPA;
-      } else if (smallExp & 2) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); 
-	MUL(smallExp/4,pa2,pa1); SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 4) {
-	SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/8,pa1,pa2); 
-	SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 8) {
-	SQR(pa1,pa2); MUL(smallExp/16,pa2,pa1); SQR(pa1,pa2); 
-	SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
-      } else {
-	abort();
-      }
-    } else if (window_bits == 5) {
-      if (!smallExp) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 1) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	SQR(pa1,pa2); MUL(smallExp/2,pa2,pa1);
-      } else if (smallExp & 2) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	MUL(smallExp/4,pa1,pa2); SQR(pa2,pa1);
-      } else if (smallExp & 4) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); 
-	MUL(smallExp/8,pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
-      } else if (smallExp & 8) {
-	SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/16,pa1,pa2); 
-	SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
-      } else if (smallExp & 0x10) {
-	SQR(pa1,pa2); MUL(smallExp/32,pa2,pa1); SQR(pa1,pa2); 
-	SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
-      } else {
-	abort();
-      }
-    } else if (window_bits == 6) {
-      if (!smallExp) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	SQR(pa1,pa2); SQR(pa2,pa1);
-      } else if (smallExp & 1) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/2,pa1,pa2); SWAPPA;
-      } else if (smallExp & 2) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	SQR(pa1,pa2); MUL(smallExp/4,pa2,pa1); SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 4) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	MUL(smallExp/8,pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 8) {
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); 
-	MUL(smallExp/16,pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 0x10) {
-	SQR(pa1,pa2); SQR(pa2,pa1); MUL(smallExp/32,pa1,pa2); 
-	SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
-      } else if (smallExp & 0x20) {
-	SQR(pa1,pa2); MUL(smallExp/64,pa2,pa1); SQR(pa1,pa2); 
-	SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SWAPPA;
-      } else {
-	abort();
-      }
-    } else {
-      abort();
-    }
-  }
-
-  res = s_mp_redc(pa1, mmm);
-  mp_exch(pa1, result);
-
-CLEANUP:
-  mp_clear(&accum1);
-  mp_clear(&accum2);
-  mp_clear(&power2);
-  for (i = 0; i < odd_ints; ++i) {
-    mp_clear(oddPowers + i);
-  }
-  return res;
-}
-#undef SQR
-#undef MUL
-
-#ifdef MP_USING_CACHE_SAFE_MOD_EXP
-unsigned int mp_using_cache_safe_exp = 1;
-#endif
-
-mp_err mp_set_safe_modexp(int value) 
-{
-#ifdef MP_USING_CACHE_SAFE_MOD_EXP
- mp_using_cache_safe_exp = value;
- return MP_OKAY;
-#else
- if (value == 0) {
-   return MP_OKAY;
- }
- return MP_BADARG;
-#endif
-}
-
-#ifdef MP_USING_CACHE_SAFE_MOD_EXP
-#define WEAVE_WORD_SIZE 4
-
-#ifndef MP_CHAR_STORE_SLOW
-/*
- * mpi_to_weave takes an array of bignums, a matrix in which each bignum 
- * occupies all the columns of a row, and transposes it into a matrix in 
- * which each bignum occupies a column of every row.  The first row of the
- * input matrix becomes the first column of the output matrix.  The n'th
- * row of input becomes the n'th column of output.  The input data is said
- * to be "interleaved" or "woven" into the output matrix.
- *
- * The array of bignums is left in this woven form.  Each time a single
- * bignum value is needed, it is recreated by fetching the n'th column, 
- * forming a single row which is the new bignum.
- *
- * The purpose of this interleaving is make it impossible to determine which
- * of the bignums is being used in any one operation by examining the pattern
- * of cache misses.
- *
- * The weaving function does not transpose the entire input matrix in one call.
- * It transposes 4 rows of mp_ints into their respective columns of output.
- *
- * There are two different implementations of the weaving and unweaving code
- * in this file.  One uses byte loads and stores.  The second uses loads and
- * stores of mp_weave_word size values.  The weaved forms of these two 
- * implementations differ.  Consequently, each one has its own explanation.
- *
- * Here is the explanation for the byte-at-a-time implementation.
- *
- * This implementation treats each mp_int bignum as an array of bytes, 
- * rather than as an array of mp_digits.  It stores those bytes as a 
- * column of bytes in the output matrix.  It doesn't care if the machine
- * uses big-endian or little-endian byte ordering within mp_digits.
- * The first byte of the mp_digit array becomes the first byte in the output
- * column, regardless of whether that byte is the MSB or LSB of the mp_digit.
- *
- * "bignums" is an array of mp_ints.
- * It points to four rows, four mp_ints, a subset of a larger array of mp_ints.
- *
- * "weaved" is the weaved output matrix. 
- * The first byte of bignums[0] is stored in weaved[0].
- * 
- * "nBignums" is the total number of bignums in the array of which "bignums" 
- * is a part.  
- *
- * "nDigits" is the size in mp_digits of each mp_int in the "bignums" array. 
- * mp_ints that use less than nDigits digits are logically padded with zeros 
- * while being stored in the weaved array.
- */
-mp_err mpi_to_weave(const mp_int  *bignums, 
-                    unsigned char *weaved, 
-		    mp_size nDigits,  /* in each mp_int of input */
-		    mp_size nBignums) /* in the entire source array */
-{
-  mp_size i;
-  unsigned char * endDest = weaved + (nDigits * nBignums * sizeof(mp_digit));
-
-  for (i=0; i < WEAVE_WORD_SIZE; i++) {
-    mp_size used = MP_USED(&bignums[i]);
-    unsigned char *pSrc   = (unsigned char *)MP_DIGITS(&bignums[i]);
-    unsigned char *endSrc = pSrc + (used * sizeof(mp_digit));
-    unsigned char *pDest  = weaved + i;
-
-    ARGCHK(MP_SIGN(&bignums[i]) == MP_ZPOS, MP_BADARG);
-    ARGCHK(used <= nDigits, MP_BADARG);
-
-    for (; pSrc < endSrc; pSrc++) {
-      *pDest = *pSrc;
-      pDest += nBignums;
-    }
-    while (pDest < endDest) {
-      *pDest = 0;
-      pDest += nBignums;
-    }
-  }
-
-  return MP_OKAY;
-}
-
-/* Reverse the operation above for one mp_int.
- * Reconstruct one mp_int from its column in the weaved array.
- * "pSrc" points to the offset into the weave array of the bignum we 
- * are going to reconstruct.
- */
-mp_err weave_to_mpi(mp_int *a,                /* output, result */
-                    const unsigned char *pSrc, /* input, byte matrix */
-		    mp_size nDigits,          /* per mp_int output */
-		    mp_size nBignums)         /* bignums in weaved matrix */
-{
-  unsigned char *pDest   = (unsigned char *)MP_DIGITS(a);
-  unsigned char *endDest = pDest + (nDigits * sizeof(mp_digit));
-
-  MP_SIGN(a) = MP_ZPOS;
-  MP_USED(a) = nDigits;
-
-  for (; pDest < endDest; pSrc += nBignums, pDest++) {
-    *pDest = *pSrc;
-  }
-  s_mp_clamp(a);
-  return MP_OKAY;
-}
-
-#else
-
-/* Need a primitive that we know is 32 bits long... */
-/* this is true on all modern processors we know of today*/
-typedef unsigned int mp_weave_word;
-
-/*
- * on some platforms character stores into memory is very expensive since they
- * generate a read/modify/write operation on the bus. On those platforms
- * we need to do integer writes to the bus. Because of some unrolled code,
- * in this current code the size of mp_weave_word must be four. The code that
- * makes this assumption explicity is called out. (on some platforms a write
- * of 4 bytes still requires a single read-modify-write operation.
- *
- * This function is takes the identical parameters as the function above, 
- * however it lays out the final array differently. Where the previous function
- * treats the mpi_int as an byte array, this function treats it as an array of
- * mp_digits where each digit is stored in big endian order.
- * 
- * since we need to interleave on a byte by byte basis, we need to collect 
- * several mpi structures together into a single uint32 before we write. We
- * also need to make sure the uint32 is arranged so that the first value of 
- * the first array winds up in b[0]. This means construction of that uint32
- * is endian specific (even though the layout of the mp_digits in the array 
- * is always big endian).
- *
- * The final data is stored as follows :
- *
- * Our same logical array p array, m is sizeof(mp_digit),
- * N is still count and n is now b_size. If we define p[i].digit[j]0 as the 
- * most significant byte of the word p[i].digit[j], p[i].digit[j]1 as 
- * the next most significant byte of p[i].digit[j], ...  and p[i].digit[j]m-1
- * is the least significant byte. 
- * Our array would look like:
- * p[0].digit[0]0     p[1].digit[0]0    ...  p[N-2].digit[0]0    p[N-1].digit[0]0
- * p[0].digit[0]1     p[1].digit[0]1    ...  p[N-2].digit[0]1    p[N-1].digit[0]1
- *                .                                         .
- * p[0].digit[0]m-1   p[1].digit[0]m-1  ...  p[N-2].digit[0]m-1  p[N-1].digit[0]m-1
- * p[0].digit[1]0     p[1].digit[1]0    ...  p[N-2].digit[1]0    p[N-1].digit[1]0
- *                .                                         .
- *                .                                         .
- * p[0].digit[n-1]m-2 p[1].digit[n-1]m-2 ... p[N-2].digit[n-1]m-2 p[N-1].digit[n-1]m-2
- * p[0].digit[n-1]m-1 p[1].digit[n-1]m-1 ... p[N-2].digit[n-1]m-1 p[N-1].digit[n-1]m-1 
- *
- */
-mp_err mpi_to_weave(const mp_int *a, unsigned char *b, 
-					mp_size b_size, mp_size count)
-{
-  mp_size i;
-  mp_digit *digitsa0;
-  mp_digit *digitsa1;
-  mp_digit *digitsa2;
-  mp_digit *digitsa3;
-  mp_size   useda0;
-  mp_size   useda1;
-  mp_size   useda2;
-  mp_size   useda3;
-  mp_weave_word *weaved = (mp_weave_word *)b;
-
-  count = count/sizeof(mp_weave_word);
-
-  /* this code pretty much depends on this ! */
-#if MP_ARGCHK == 2
-  assert(WEAVE_WORD_SIZE == 4); 
-  assert(sizeof(mp_weave_word) == 4);
-#endif
-
-  digitsa0 = MP_DIGITS(&a[0]);
-  digitsa1 = MP_DIGITS(&a[1]);
-  digitsa2 = MP_DIGITS(&a[2]);
-  digitsa3 = MP_DIGITS(&a[3]);
-  useda0 = MP_USED(&a[0]);
-  useda1 = MP_USED(&a[1]);
-  useda2 = MP_USED(&a[2]);
-  useda3 = MP_USED(&a[3]);
-
-  ARGCHK(MP_SIGN(&a[0]) == MP_ZPOS, MP_BADARG);
-  ARGCHK(MP_SIGN(&a[1]) == MP_ZPOS, MP_BADARG);
-  ARGCHK(MP_SIGN(&a[2]) == MP_ZPOS, MP_BADARG);
-  ARGCHK(MP_SIGN(&a[3]) == MP_ZPOS, MP_BADARG);
-  ARGCHK(useda0 <= b_size, MP_BADARG);
-  ARGCHK(useda1 <= b_size, MP_BADARG);
-  ARGCHK(useda2 <= b_size, MP_BADARG);
-  ARGCHK(useda3 <= b_size, MP_BADARG);
-
-#define SAFE_FETCH(digit, used, word) ((word) < (used) ? (digit[word]) : 0)
-
-  for (i=0; i < b_size; i++) {
-    mp_digit d0 = SAFE_FETCH(digitsa0,useda0,i);
-    mp_digit d1 = SAFE_FETCH(digitsa1,useda1,i);
-    mp_digit d2 = SAFE_FETCH(digitsa2,useda2,i);
-    mp_digit d3 = SAFE_FETCH(digitsa3,useda3,i);
-    register mp_weave_word acc;
-
-/*
- * ONE_STEP takes the MSB of each of our current digits and places that
- * byte in the appropriate position for writing to the weaved array.
- *  On little endian:
- *   b3 b2 b1 b0
- *  On big endian:
- *   b0 b1 b2 b3
- *  When the data is written it would always wind up:
- *   b[0] = b0
- *   b[1] = b1
- *   b[2] = b2
- *   b[3] = b3
- *
- * Once we've written the MSB, we shift the whole digit up left one
- * byte, putting the Next Most Significant Byte in the MSB position,
- * so we we repeat the next one step that byte will be written.
- * NOTE: This code assumes sizeof(mp_weave_word) and MP_WEAVE_WORD_SIZE
- * is 4.
- */
-#ifdef MP_IS_LITTLE_ENDIAN 
-#define MPI_WEAVE_ONE_STEP \
-    acc  = (d0 >> (MP_DIGIT_BIT-8))  & 0x000000ff; d0 <<= 8; /*b0*/ \
-    acc |= (d1 >> (MP_DIGIT_BIT-16)) & 0x0000ff00; d1 <<= 8; /*b1*/ \
-    acc |= (d2 >> (MP_DIGIT_BIT-24)) & 0x00ff0000; d2 <<= 8; /*b2*/ \
-    acc |= (d3 >> (MP_DIGIT_BIT-32)) & 0xff000000; d3 <<= 8; /*b3*/ \
-    *weaved = acc; weaved += count;
-#else 
-#define MPI_WEAVE_ONE_STEP \
-    acc  = (d0 >> (MP_DIGIT_BIT-32)) & 0xff000000; d0 <<= 8; /*b0*/ \
-    acc |= (d1 >> (MP_DIGIT_BIT-24)) & 0x00ff0000; d1 <<= 8; /*b1*/ \
-    acc |= (d2 >> (MP_DIGIT_BIT-16)) & 0x0000ff00; d2 <<= 8; /*b2*/ \
-    acc |= (d3 >> (MP_DIGIT_BIT-8))  & 0x000000ff; d3 <<= 8; /*b3*/ \
-    *weaved = acc; weaved += count;
-#endif 
-   switch (sizeof(mp_digit)) {
-   case 32:
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-   case 16:
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-   case 8:
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-   case 4:
-    MPI_WEAVE_ONE_STEP
-    MPI_WEAVE_ONE_STEP
-   case 2:
-    MPI_WEAVE_ONE_STEP
-   case 1:
-    MPI_WEAVE_ONE_STEP
-    break;
-   }
-  }
-
-  return MP_OKAY;
-}
-
-/* reverse the operation above for one entry.
- * b points to the offset into the weave array of the power we are
- * calculating */
-mp_err weave_to_mpi(mp_int *a, const unsigned char *b, 
-					mp_size b_size, mp_size count)
-{
-  mp_digit *pb = MP_DIGITS(a);
-  mp_digit *end = &pb[b_size];
-
-  MP_SIGN(a) = MP_ZPOS;
-  MP_USED(a) = b_size;
-
-  for (; pb < end; pb++) {
-    register mp_digit digit;
-
-    digit = *b << 8; b += count;
-#define MPI_UNWEAVE_ONE_STEP  digit |= *b; b += count; digit = digit << 8;
-    switch (sizeof(mp_digit)) {
-    case 32:
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-    case 16:
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-    case 8:
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-    case 4:
-	MPI_UNWEAVE_ONE_STEP 
-	MPI_UNWEAVE_ONE_STEP 
-    case 2:
-	break;
-    }
-    digit |= *b; b += count; 
-
-    *pb = digit;
-  }
-  s_mp_clamp(a);
-  return MP_OKAY;
-}
-#endif
-
-
-#define SQR(a,b) \
-  MP_CHECKOK( mp_sqr(a, b) );\
-  MP_CHECKOK( s_mp_redc(b, mmm) )
-
-#if defined(MP_MONT_USE_MP_MUL)
-#define MUL_NOWEAVE(x,a,b) \
-  MP_CHECKOK( mp_mul(a, x, b) ); \
-  MP_CHECKOK( s_mp_redc(b, mmm) ) 
-#else
-#define MUL_NOWEAVE(x,a,b) \
-  MP_CHECKOK( s_mp_mul_mont(a, x, b, mmm) )
-#endif
-
-#define MUL(x,a,b) \
-  MP_CHECKOK( weave_to_mpi(&tmp, powers + (x), nLen, num_powers) ); \
-  MUL_NOWEAVE(&tmp,a,b)
-
-#define SWAPPA ptmp = pa1; pa1 = pa2; pa2 = ptmp
-#define MP_ALIGN(x,y) ((((ptrdiff_t)(x))+((y)-1))&(((ptrdiff_t)0)-(y)))
-
-/* Do modular exponentiation using integer multiply code. */
-mp_err mp_exptmod_safe_i(const mp_int *   montBase, 
-                    const mp_int *   exponent, 
-		    const mp_int *   modulus, 
-		    mp_int *         result, 
-		    mp_mont_modulus *mmm, 
-		    int              nLen, 
-		    mp_size          bits_in_exponent, 
-		    mp_size          window_bits,
-		    mp_size          num_powers)
-{
-  mp_int *pa1, *pa2, *ptmp;
-  mp_size i;
-  mp_size first_window;
-  mp_err  res;
-  int     expOff;
-  mp_int  accum1, accum2, accum[WEAVE_WORD_SIZE];
-  mp_int  tmp;
-  unsigned char *powersArray;
-  unsigned char *powers;
-
-  MP_DIGITS(&accum1) = 0;
-  MP_DIGITS(&accum2) = 0;
-  MP_DIGITS(&accum[0]) = 0;
-  MP_DIGITS(&accum[1]) = 0;
-  MP_DIGITS(&accum[2]) = 0;
-  MP_DIGITS(&accum[3]) = 0;
-  MP_DIGITS(&tmp) = 0;
-
-  powersArray = (unsigned char *)malloc(num_powers*(nLen*sizeof(mp_digit)+1));
-  if (powersArray == NULL) {
-    res = MP_MEM;
-    goto CLEANUP;
-  }
-
-  /* powers[i] = base ** (i); */
-  powers = (unsigned char *)MP_ALIGN(powersArray,num_powers);
-
-  /* grab the first window value. This allows us to preload accumulator1
-   * and save a conversion, some squares and a multiple*/
-  MP_CHECKOK( mpl_get_bits(exponent, 
-				bits_in_exponent-window_bits, window_bits) );
-  first_window = (mp_size)res;
-
-  MP_CHECKOK( mp_init_size(&accum1, 3 * nLen + 2) );
-  MP_CHECKOK( mp_init_size(&accum2, 3 * nLen + 2) );
-  MP_CHECKOK( mp_init_size(&tmp, 3 * nLen + 2) );
-
-  /* build the first WEAVE_WORD powers inline */
-  /* if WEAVE_WORD_SIZE is not 4, this code will have to change */
-  if (num_powers > 2) {
-    MP_CHECKOK( mp_init_size(&accum[0], 3 * nLen + 2) );
-    MP_CHECKOK( mp_init_size(&accum[1], 3 * nLen + 2) );
-    MP_CHECKOK( mp_init_size(&accum[2], 3 * nLen + 2) );
-    MP_CHECKOK( mp_init_size(&accum[3], 3 * nLen + 2) );
-    mp_set(&accum[0], 1);
-    MP_CHECKOK( s_mp_to_mont(&accum[0], mmm, &accum[0]) );
-    MP_CHECKOK( mp_copy(montBase, &accum[1]) );
-    SQR(montBase, &accum[2]);
-    MUL_NOWEAVE(montBase, &accum[2], &accum[3]);
-    MP_CHECKOK( mpi_to_weave(accum, powers, nLen, num_powers) );
-    if (first_window < 4) {
-      MP_CHECKOK( mp_copy(&accum[first_window], &accum1) );
-      first_window = num_powers;
-    }
-  } else {
-      if (first_window == 0) {
-        mp_set(&accum1, 1);
-        MP_CHECKOK( s_mp_to_mont(&accum1, mmm, &accum1) );
-      } else {
-        /* assert first_window == 1? */
-        MP_CHECKOK( mp_copy(montBase, &accum1) );
-      }
-  }
-
-  /*
-   * calculate all the powers in the powers array.
-   * this adds 2**(k-1)-2 square operations over just calculating the
-   * odd powers where k is the window size in the two other mp_modexpt
-   * implementations in this file. We will get some of that
-   * back by not needing the first 'k' squares and one multiply for the 
-   * first window */ 
-  for (i = WEAVE_WORD_SIZE; i < num_powers; i++) {
-    int acc_index = i & (WEAVE_WORD_SIZE-1); /* i % WEAVE_WORD_SIZE */
-    if ( i & 1 ) {
-      MUL_NOWEAVE(montBase, &accum[acc_index-1] , &accum[acc_index]);
-      /* we've filled the array do our 'per array' processing */
-      if (acc_index == (WEAVE_WORD_SIZE-1)) {
-        MP_CHECKOK( mpi_to_weave(accum, powers + i - (WEAVE_WORD_SIZE-1),
-							 nLen, num_powers) );
-
-        if (first_window <= i) {
-          MP_CHECKOK( mp_copy(&accum[first_window & (WEAVE_WORD_SIZE-1)], 
-								&accum1) );
-          first_window = num_powers;
-        }
-      }
-    } else {
-      /* up to 8 we can find 2^i-1 in the accum array, but at 8 we our source
-       * and target are the same so we need to copy.. After that, the
-       * value is overwritten, so we need to fetch it from the stored
-       * weave array */
-      if (i > 2* WEAVE_WORD_SIZE) {
-        MP_CHECKOK(weave_to_mpi(&accum2, powers+i/2, nLen, num_powers));
-        SQR(&accum2, &accum[acc_index]);
-      } else {
-	int half_power_index = (i/2) & (WEAVE_WORD_SIZE-1);
-	if (half_power_index == acc_index) {
-	   /* copy is cheaper than weave_to_mpi */
-	   MP_CHECKOK(mp_copy(&accum[half_power_index], &accum2));
-	   SQR(&accum2,&accum[acc_index]);
-	} else {
-	   SQR(&accum[half_power_index],&accum[acc_index]);
-	}
-      }
-    }
-  }
-  /* if the accum1 isn't set, Then there is something wrong with our logic 
-   * above and is an internal programming error. 
-   */
-#if MP_ARGCHK == 2
-  assert(MP_USED(&accum1) != 0);
-#endif
-
-  /* set accumulator to montgomery residue of 1 */
-  pa1 = &accum1;
-  pa2 = &accum2;
-
-  for (expOff = bits_in_exponent - window_bits*2; expOff >= 0; expOff -= window_bits) {
-    mp_size smallExp;
-    MP_CHECKOK( mpl_get_bits(exponent, expOff, window_bits) );
-    smallExp = (mp_size)res;
-
-    /* handle unroll the loops */
-    switch (window_bits) {
-    case 1:
-	if (!smallExp) {
-	    SQR(pa1,pa2); SWAPPA;
-	} else if (smallExp & 1) {
-	    SQR(pa1,pa2); MUL_NOWEAVE(montBase,pa2,pa1);
-	} else {
-	    abort();
-	}
-	break;
-    case 6:
-	SQR(pa1,pa2); SQR(pa2,pa1); 
-	/* fall through */
-    case 4:
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1);
-	MUL(smallExp, pa1,pa2); SWAPPA;
-	break;
-    case 5:
-	SQR(pa1,pa2); SQR(pa2,pa1); SQR(pa1,pa2); SQR(pa2,pa1); 
-	SQR(pa1,pa2); MUL(smallExp,pa2,pa1);
-	break;
-    default:
-	abort(); /* could do a loop? */
-    }
-  }
-
-  res = s_mp_redc(pa1, mmm);
-  mp_exch(pa1, result);
-
-CLEANUP:
-  mp_clear(&accum1);
-  mp_clear(&accum2);
-  mp_clear(&accum[0]);
-  mp_clear(&accum[1]);
-  mp_clear(&accum[2]);
-  mp_clear(&accum[3]);
-  mp_clear(&tmp);
-  /* PORT_Memset(powers,0,num_powers*nLen*sizeof(mp_digit)); */
-  free(powersArray);
-  return res;
-}
-#undef SQR
-#undef MUL
-#endif
-
-mp_err mp_exptmod(const mp_int *inBase, const mp_int *exponent, 
-		  const mp_int *modulus, mp_int *result)
-{
-  const mp_int *base;
-  mp_size bits_in_exponent, i, window_bits, odd_ints;
-  mp_err  res;
-  int     nLen;
-  mp_int  montBase, goodBase;
-  mp_mont_modulus mmm;
-#ifdef MP_USING_CACHE_SAFE_MOD_EXP
-  static unsigned int max_window_bits;
-#endif
-
-  /* function for computing n0prime only works if n0 is odd */
-  if (!mp_isodd(modulus))
-    return s_mp_exptmod(inBase, exponent, modulus, result);
-
-  MP_DIGITS(&montBase) = 0;
-  MP_DIGITS(&goodBase) = 0;
-
-  if (mp_cmp(inBase, modulus) < 0) {
-    base = inBase;
-  } else {
-    MP_CHECKOK( mp_init(&goodBase) );
-    base = &goodBase;
-    MP_CHECKOK( mp_mod(inBase, modulus, &goodBase) );
-  }
-
-  nLen  = MP_USED(modulus);
-  MP_CHECKOK( mp_init_size(&montBase, 2 * nLen + 2) );
-
-  mmm.N = *modulus;			/* a copy of the mp_int struct */
-
-  /* compute n0', given n0, n0' = -(n0 ** -1) mod MP_RADIX
-  **		where n0 = least significant mp_digit of N, the modulus.
-  */
-  mmm.n0prime = 0 - s_mp_invmod_radix( MP_DIGIT(modulus, 0) );
-
-  MP_CHECKOK( s_mp_to_mont(base, &mmm, &montBase) );
-
-  bits_in_exponent = mpl_significant_bits(exponent);
-#ifdef MP_USING_CACHE_SAFE_MOD_EXP
-  if (mp_using_cache_safe_exp) {
-    if (bits_in_exponent > 780)
-	window_bits = 6;
-    else if (bits_in_exponent > 256)
-	window_bits = 5;
-    else if (bits_in_exponent > 20)
-	window_bits = 4;
-       /* RSA public key exponents are typically under 20 bits (common values 
-        * are: 3, 17, 65537) and a 4-bit window is inefficient
-        */
-    else 
-	window_bits = 1;
-  } else
-#endif
-  if (bits_in_exponent > 480)
-    window_bits = 6;
-  else if (bits_in_exponent > 160)
-    window_bits = 5;
-  else if (bits_in_exponent > 20)
-    window_bits = 4;
-  /* RSA public key exponents are typically under 20 bits (common values 
-   * are: 3, 17, 65537) and a 4-bit window is inefficient
-   */
-  else 
-    window_bits = 1;
-
-#ifdef MP_USING_CACHE_SAFE_MOD_EXP
-  /*
-   * clamp the window size based on
-   * the cache line size.
-   */
-  if (!max_window_bits) {
-    unsigned long cache_size = s_mpi_getProcessorLineSize();
-    /* processor has no cache, use 'fast' code always */
-    if (cache_size == 0) {
-      mp_using_cache_safe_exp = 0;
-    } 
-    if ((cache_size == 0) || (cache_size >= 64)) {
-      max_window_bits = 6;
-    } else if (cache_size >= 32) {
-      max_window_bits = 5;
-    } else if (cache_size >= 16) {
-      max_window_bits = 4;
-    } else max_window_bits = 1; /* should this be an assert? */
-  }
-
-  /* clamp the window size down before we caclulate bits_in_exponent */
-  if (mp_using_cache_safe_exp) {
-    if (window_bits > max_window_bits) {
-      window_bits = max_window_bits;
-    }
-  }
-#endif
-
-  odd_ints = 1 << (window_bits - 1);
-  i = bits_in_exponent % window_bits;
-  if (i != 0) {
-    bits_in_exponent += window_bits - i;
-  } 
-
-#ifdef MP_USING_MONT_MULF
-  if (mp_using_mont_mulf) {
-    MP_CHECKOK( s_mp_pad(&montBase, nLen) );
-    res = mp_exptmod_f(&montBase, exponent, modulus, result, &mmm, nLen, 
-		     bits_in_exponent, window_bits, odd_ints);
-  } else
-#endif
-#ifdef MP_USING_CACHE_SAFE_MOD_EXP
-  if (mp_using_cache_safe_exp) {
-    res = mp_exptmod_safe_i(&montBase, exponent, modulus, result, &mmm, nLen, 
-		     bits_in_exponent, window_bits, 1 << window_bits);
-  } else
-#endif
-  res = mp_exptmod_i(&montBase, exponent, modulus, result, &mmm, nLen, 
-		     bits_in_exponent, window_bits, odd_ints);
-
-CLEANUP:
-  mp_clear(&montBase);
-  mp_clear(&goodBase);
-  /* Don't mp_clear mmm.N because it is merely a copy of modulus.
-  ** Just zap it.
-  */
-  memset(&mmm, 0, sizeof mmm);
-  return res;
-}