--- /dev/null
+/* mpn_get_str -- Convert a MSIZE long limb vector pointed to by MPTR
+ to a printable string in STR in base BASE.
+
+Copyright (C) 1991, 1992, 1993, 1994, 1996 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 Library General Public License as published by
+the Free Software Foundation; either version 2 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 Library General Public
+License for more details.
+
+You should have received a copy of the GNU Library General Public License
+along with the GNU MP Library; see the file COPYING.LIB. If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+
+/* Convert the limb vector pointed to by MPTR and MSIZE long to a
+ char array, using base BASE for the result array. Store the
+ result in the character array STR. STR must point to an array with
+ space for the largest possible number represented by a MSIZE long
+ limb vector + 1 extra character.
+
+ The result is NOT in Ascii, to convert it to printable format, add
+ '0' or 'A' depending on the base and range.
+
+ Return the number of digits in the result string.
+ This may include some leading zeros.
+
+ The limb vector pointed to by MPTR is clobbered. */
+
+size_t
+mpn_get_str (str, base, mptr, msize)
+ unsigned char *str;
+ int base;
+ mp_ptr mptr;
+ mp_size_t msize;
+{
+ mp_limb_t big_base;
+#if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
+ int normalization_steps;
+#endif
+#if UDIV_TIME > 2 * UMUL_TIME
+ mp_limb_t big_base_inverted;
+#endif
+ unsigned int dig_per_u;
+ mp_size_t out_len;
+ register unsigned char *s;
+
+ big_base = __mp_bases[base].big_base;
+
+ s = str;
+
+ /* Special case zero, as the code below doesn't handle it. */
+ if (msize == 0)
+ {
+ s[0] = 0;
+ return 1;
+ }
+
+ if ((base & (base - 1)) == 0)
+ {
+ /* The base is a power of 2. Make conversion from most
+ significant side. */
+ mp_limb_t n1, n0;
+ register int bits_per_digit = big_base;
+ register int x;
+ register int bit_pos;
+ register int i;
+
+ n1 = mptr[msize - 1];
+ count_leading_zeros (x, n1);
+
+ /* BIT_POS should be R when input ends in least sign. nibble,
+ R + bits_per_digit * n when input ends in n:th least significant
+ nibble. */
+
+ {
+ int bits;
+
+ bits = BITS_PER_MP_LIMB * msize - x;
+ x = bits % bits_per_digit;
+ if (x != 0)
+ bits += bits_per_digit - x;
+ bit_pos = bits - (msize - 1) * BITS_PER_MP_LIMB;
+ }
+
+ /* Fast loop for bit output. */
+ i = msize - 1;
+ for (;;)
+ {
+ bit_pos -= bits_per_digit;
+ while (bit_pos >= 0)
+ {
+ *s++ = (n1 >> bit_pos) & ((1 << bits_per_digit) - 1);
+ bit_pos -= bits_per_digit;
+ }
+ i--;
+ if (i < 0)
+ break;
+ n0 = (n1 << -bit_pos) & ((1 << bits_per_digit) - 1);
+ n1 = mptr[i];
+ bit_pos += BITS_PER_MP_LIMB;
+ *s++ = n0 | (n1 >> bit_pos);
+ }
+
+ *s = 0;
+
+ return s - str;
+ }
+ else
+ {
+ /* General case. The base is not a power of 2. Make conversion
+ from least significant end. */
+
+ /* If udiv_qrnnd only handles divisors with the most significant bit
+ set, prepare BIG_BASE for being a divisor by shifting it to the
+ left exactly enough to set the most significant bit. */
+#if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
+ count_leading_zeros (normalization_steps, big_base);
+ big_base <<= normalization_steps;
+#if UDIV_TIME > 2 * UMUL_TIME
+ /* Get the fixed-point approximation to 1/(BIG_BASE << NORMALIZATION_STEPS). */
+ big_base_inverted = __mp_bases[base].big_base_inverted;
+#endif
+#endif
+
+ dig_per_u = __mp_bases[base].chars_per_limb;
+ out_len = ((size_t) msize * BITS_PER_MP_LIMB
+ * __mp_bases[base].chars_per_bit_exactly) + 1;
+ s += out_len;
+
+ while (msize != 0)
+ {
+ int i;
+ mp_limb_t n0, n1;
+
+#if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
+ /* If we shifted BIG_BASE above, shift the dividend too, to get
+ the right quotient. We need to do this every loop,
+ since the intermediate quotients are OK, but the quotient from
+ one turn in the loop is going to be the dividend in the
+ next turn, and the dividend needs to be up-shifted. */
+ if (normalization_steps != 0)
+ {
+ n0 = mpn_lshift (mptr, mptr, msize, normalization_steps);
+
+ /* If the shifting gave a carry out limb, store it and
+ increase the length. */
+ if (n0 != 0)
+ {
+ mptr[msize] = n0;
+ msize++;
+ }
+ }
+#endif
+
+ /* Divide the number at TP with BIG_BASE to get a quotient and a
+ remainder. The remainder is our new digit in base BIG_BASE. */
+ i = msize - 1;
+ n1 = mptr[i];
+
+ if (n1 >= big_base)
+ n1 = 0;
+ else
+ {
+ msize--;
+ i--;
+ }
+
+ for (; i >= 0; i--)
+ {
+ n0 = mptr[i];
+#if UDIV_TIME > 2 * UMUL_TIME
+ udiv_qrnnd_preinv (mptr[i], n1, n1, n0, big_base, big_base_inverted);
+#else
+ udiv_qrnnd (mptr[i], n1, n1, n0, big_base);
+#endif
+ }
+
+#if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
+ /* If we shifted above (at previous UDIV_NEEDS_NORMALIZATION tests)
+ the remainder will be up-shifted here. Compensate. */
+ n1 >>= normalization_steps;
+#endif
+
+ /* Convert N1 from BIG_BASE to a string of digits in BASE
+ using single precision operations. */
+ for (i = dig_per_u - 1; i >= 0; i--)
+ {
+ *--s = n1 % base;
+ n1 /= base;
+ if (n1 == 0 && msize == 0)
+ break;
+ }
+ }
+
+ while (s != str)
+ *--s = 0;
+ return out_len;
+ }
+}
projects / ghc-hetmet.git / blobdiff