--- /dev/null
+/* mpn_set_str (mp_ptr res_ptr, const char *str, size_t str_len, int base) --
+ Convert a STR_LEN long base BASE byte string pointed to by STR to a limb
+ vector pointed to by RES_PTR. Return the number of limbs in RES_PTR.
+
+ Contributed to the GNU project by Torbjorn Granlund.
+
+ THE FUNCTIONS IN THIS FILE, EXCEPT mpn_set_str, ARE INTERNAL WITH A MUTABLE
+ INTERFACE. IT IS ONLY SAFE TO REACH THEM THROUGH DOCUMENTED INTERFACES. IN
+ FACT, IT IS ALMOST GUARANTEED THAT THEY WILL CHANGE OR DISAPPEAR IN A FUTURE
+ GNU MP RELEASE.
+
+Copyright 1991, 1992, 1993, 1994, 1996, 2000, 2001, 2002, 2004, 2006, 2007,
+2008 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The GNU MP Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
+
+
+/* TODO:
+
+ Perhaps do not compute the highest power?
+ Instead, multiply twice by the 2nd highest power:
+
+ _______
+ |_______| hp
+ |_______| pow
+ _______________
+ |_______________| final result
+
+
+ _______
+ |_______| hp
+ |___| pow[-1]
+ ___________
+ |___________| intermediate result
+ |___| pow[-1]
+ _______________
+ |_______________| final result
+
+ Generalizing that idea, perhaps we should make powtab contain successive
+ cubes, not squares.
+*/
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+
+mp_size_t
+mpn_set_str (mp_ptr rp, const unsigned char *str, size_t str_len, int base)
+{
+ if (POW2_P (base))
+ {
+ /* The base is a power of 2. Read the input string from least to most
+ significant character/digit. */
+
+ const unsigned char *s;
+ int next_bitpos;
+ mp_limb_t res_digit;
+ mp_size_t size;
+ int bits_per_indigit = __mp_bases[base].big_base;
+
+ size = 0;
+ res_digit = 0;
+ next_bitpos = 0;
+
+ for (s = str + str_len - 1; s >= str; s--)
+ {
+ int inp_digit = *s;
+
+ res_digit |= ((mp_limb_t) inp_digit << next_bitpos) & GMP_NUMB_MASK;
+ next_bitpos += bits_per_indigit;
+ if (next_bitpos >= GMP_NUMB_BITS)
+ {
+ rp[size++] = res_digit;
+ next_bitpos -= GMP_NUMB_BITS;
+ res_digit = inp_digit >> (bits_per_indigit - next_bitpos);
+ }
+ }
+
+ if (res_digit != 0)
+ rp[size++] = res_digit;
+ return size;
+ }
+
+ if (BELOW_THRESHOLD (str_len, SET_STR_PRECOMPUTE_THRESHOLD))
+ return mpn_bc_set_str (rp, str, str_len, base);
+ else
+ {
+ mp_ptr powtab_mem, tp;
+ powers_t powtab[GMP_LIMB_BITS];
+ int chars_per_limb;
+ mp_size_t size;
+ mp_size_t un;
+ TMP_DECL;
+
+ TMP_MARK;
+
+ chars_per_limb = __mp_bases[base].chars_per_limb;
+
+ un = str_len / chars_per_limb + 1;
+
+ /* Allocate one large block for the powers of big_base. */
+ powtab_mem = TMP_BALLOC_LIMBS (mpn_dc_set_str_powtab_alloc (un));
+
+ mpn_set_str_compute_powtab (powtab, powtab_mem, un, base);
+
+ tp = TMP_BALLOC_LIMBS (mpn_dc_set_str_itch (un));
+ size = mpn_dc_set_str (rp, str, str_len, powtab, tp);
+
+ TMP_FREE;
+ return size;
+ }
+}
+
+void
+mpn_set_str_compute_powtab (powers_t *powtab, mp_ptr powtab_mem, mp_size_t un, int base)
+{
+ mp_ptr powtab_mem_ptr;
+ long i, pi;
+ mp_size_t n;
+ mp_ptr p, t;
+ unsigned normalization_steps;
+ mp_limb_t big_base, big_base_inverted;
+ int chars_per_limb;
+ size_t digits_in_base;
+ mp_size_t shift;
+
+ powtab_mem_ptr = powtab_mem;
+
+ chars_per_limb = __mp_bases[base].chars_per_limb;
+ big_base = __mp_bases[base].big_base;
+ big_base_inverted = __mp_bases[base].big_base_inverted;
+ count_leading_zeros (normalization_steps, big_base);
+
+ p = powtab_mem_ptr;
+ powtab_mem_ptr += 1;
+
+ digits_in_base = chars_per_limb;
+
+ p[0] = big_base;
+ n = 1;
+
+ count_leading_zeros (i, un - 1);
+ i = GMP_LIMB_BITS - 1 - i;
+
+ powtab[i].p = p;
+ powtab[i].n = n;
+ powtab[i].digits_in_base = digits_in_base;
+ powtab[i].base = base;
+ powtab[i].shift = 0;
+
+ shift = 0;
+ for (pi = i - 1; pi >= 0; pi--)
+ {
+ t = powtab_mem_ptr;
+ powtab_mem_ptr += 2 * n;
+
+ ASSERT_ALWAYS (powtab_mem_ptr < powtab_mem + mpn_dc_set_str_powtab_alloc (un));
+
+ mpn_sqr_n (t, p, n);
+ n = 2 * n - 1; n += t[n] != 0;
+ digits_in_base *= 2;
+#if 1
+ if ((((un - 1) >> pi) & 2) == 0)
+ {
+ mpn_divexact_1 (t, t, n, big_base);
+ n -= t[n - 1] == 0;
+ digits_in_base -= chars_per_limb;
+ }
+#else
+ if (CLEVER_CONDITION_1 ())
+ {
+ /* perform adjustment operation of previous */
+ cy = mpn_mul_1 (p, p, n, big_base);
+ }
+ if (CLEVER_CONDITION_2 ())
+ {
+ /* perform adjustment operation of new */
+ cy = mpn_mul_1 (t, t, n, big_base);
+ }
+#endif
+ shift *= 2;
+ /* Strip low zero limbs, but be careful to keep the result divisible by
+ big_base. */
+ while (t[0] == 0 && (t[1] & ((big_base & -big_base) - 1)) == 0)
+ {
+ t++;
+ n--;
+ shift++;
+ }
+ p = t;
+ powtab[pi].p = p;
+ powtab[pi].n = n;
+ powtab[pi].digits_in_base = digits_in_base;
+ powtab[pi].base = base;
+ powtab[pi].shift = shift;
+ }
+}
+
+mp_size_t
+mpn_dc_set_str (mp_ptr rp, const unsigned char *str, size_t str_len,
+ const powers_t *powtab, mp_ptr tp)
+{
+ size_t len_lo, len_hi;
+ mp_limb_t cy;
+ mp_size_t ln, hn, n, sn;
+
+ len_lo = powtab->digits_in_base;
+
+ if (str_len <= len_lo)
+ {
+ if (BELOW_THRESHOLD (str_len, SET_STR_DC_THRESHOLD))
+ return mpn_bc_set_str (rp, str, str_len, powtab->base);
+ else
+ return mpn_dc_set_str (rp, str, str_len, powtab + 1, tp);
+ }
+
+ len_hi = str_len - len_lo;
+ ASSERT (len_lo >= len_hi);
+
+ if (BELOW_THRESHOLD (len_hi, SET_STR_DC_THRESHOLD))
+ hn = mpn_bc_set_str (tp, str, len_hi, powtab->base);
+ else
+ hn = mpn_dc_set_str (tp, str, len_hi, powtab + 1, rp);
+
+ sn = powtab->shift;
+
+ if (hn == 0)
+ {
+ MPN_ZERO (rp, powtab->n + sn);
+ }
+ else
+ {
+ if (powtab->n > hn)
+ mpn_mul (rp + sn, powtab->p, powtab->n, tp, hn);
+ else
+ mpn_mul (rp + sn, tp, hn, powtab->p, powtab->n);
+ MPN_ZERO (rp, sn);
+ }
+
+ str = str + str_len - len_lo;
+ if (BELOW_THRESHOLD (len_lo, SET_STR_DC_THRESHOLD))
+ ln = mpn_bc_set_str (tp, str, len_lo, powtab->base);
+ else
+ ln = mpn_dc_set_str (tp, str, len_lo, powtab + 1, tp + powtab->n + sn + 1);
+
+ if (ln != 0)
+ {
+ cy = mpn_add_n (rp, rp, tp, ln);
+ mpn_incr_u (rp + ln, cy);
+ }
+ n = hn + powtab->n + sn;
+ return n - (rp[n - 1] == 0);
+}
+
+mp_size_t
+mpn_bc_set_str (mp_ptr rp, const unsigned char *str, size_t str_len, int base)
+{
+ mp_size_t size;
+ size_t i;
+ long j;
+ mp_limb_t cy_limb;
+
+ mp_limb_t big_base;
+ int chars_per_limb;
+ mp_limb_t res_digit;
+
+ ASSERT (base >= 2);
+ ASSERT (base < numberof (__mp_bases));
+ ASSERT (str_len >= 1);
+
+ big_base = __mp_bases[base].big_base;
+ chars_per_limb = __mp_bases[base].chars_per_limb;
+
+ size = 0;
+ for (i = chars_per_limb; i < str_len; i += chars_per_limb)
+ {
+ res_digit = *str++;
+ if (base == 10)
+ { /* This is a common case.
+ Help the compiler to avoid multiplication. */
+ for (j = MP_BASES_CHARS_PER_LIMB_10 - 1; j != 0; j--)
+ res_digit = res_digit * 10 + *str++;
+ }
+ else
+ {
+ for (j = chars_per_limb - 1; j != 0; j--)
+ res_digit = res_digit * base + *str++;
+ }
+
+ if (size == 0)
+ {
+ if (res_digit != 0)
+ {
+ rp[0] = res_digit;
+ size = 1;
+ }
+ }
+ else
+ {
+#if HAVE_NATIVE_mpn_mul_1c
+ cy_limb = mpn_mul_1c (rp, rp, size, big_base, res_digit);
+#else
+ cy_limb = mpn_mul_1 (rp, rp, size, big_base);
+ cy_limb += mpn_add_1 (rp, rp, size, res_digit);
+#endif
+ if (cy_limb != 0)
+ rp[size++] = cy_limb;
+ }
+ }
+
+ big_base = base;
+ res_digit = *str++;
+ if (base == 10)
+ { /* This is a common case.
+ Help the compiler to avoid multiplication. */
+ for (j = str_len - (i - MP_BASES_CHARS_PER_LIMB_10) - 1; j > 0; j--)
+ {
+ res_digit = res_digit * 10 + *str++;
+ big_base *= 10;
+ }
+ }
+ else
+ {
+ for (j = str_len - (i - chars_per_limb) - 1; j > 0; j--)
+ {
+ res_digit = res_digit * base + *str++;
+ big_base *= base;
+ }
+ }
+
+ if (size == 0)
+ {
+ if (res_digit != 0)
+ {
+ rp[0] = res_digit;
+ size = 1;
+ }
+ }
+ else
+ {
+#if HAVE_NATIVE_mpn_mul_1c
+ cy_limb = mpn_mul_1c (rp, rp, size, big_base, res_digit);
+#else
+ cy_limb = mpn_mul_1 (rp, rp, size, big_base);
+ cy_limb += mpn_add_1 (rp, rp, size, res_digit);
+#endif
+ if (cy_limb != 0)
+ rp[size++] = cy_limb;
+ }
+ return size;
+}
projects / msp430-gcc.git / blobdiff