1 /* mpn_get_str -- Convert a MSIZE long limb vector pointed to by MPTR
2 to a printable string in STR in base BASE.
4 Copyright (C) 1991, 1992, 1993, 1994, 1996 Free Software Foundation, Inc.
6 This file is part of the GNU MP Library.
8 The GNU MP Library is free software; you can redistribute it and/or modify
9 it under the terms of the GNU Library General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or (at your
11 option) any later version.
13 The GNU MP Library is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
16 License for more details.
18 You should have received a copy of the GNU Library General Public License
19 along with the GNU MP Library; see the file COPYING.LIB. If not, write to
20 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
21 MA 02111-1307, USA. */
28 /* Convert the limb vector pointed to by MPTR and MSIZE long to a
29 char array, using base BASE for the result array. Store the
30 result in the character array STR. STR must point to an array with
31 space for the largest possible number represented by a MSIZE long
32 limb vector + 1 extra character.
34 The result is NOT in Ascii, to convert it to printable format, add
35 '0' or 'A' depending on the base and range.
37 Return the number of digits in the result string.
38 This may include some leading zeros.
40 The limb vector pointed to by MPTR is clobbered. */
43 mpn_get_str (str, base, mptr, msize)
50 #if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
51 int normalization_steps;
53 #if UDIV_TIME > 2 * UMUL_TIME
54 mp_limb_t big_base_inverted;
56 unsigned int dig_per_u;
58 register unsigned char *s;
60 big_base = __mp_bases[base].big_base;
64 /* Special case zero, as the code below doesn't handle it. */
71 if ((base & (base - 1)) == 0)
73 /* The base is a power of 2. Make conversion from most
76 register int bits_per_digit = big_base;
82 count_leading_zeros (x, n1);
84 /* BIT_POS should be R when input ends in least sign. nibble,
85 R + bits_per_digit * n when input ends in n:th least significant
91 bits = BITS_PER_MP_LIMB * msize - x;
92 x = bits % bits_per_digit;
94 bits += bits_per_digit - x;
95 bit_pos = bits - (msize - 1) * BITS_PER_MP_LIMB;
98 /* Fast loop for bit output. */
102 bit_pos -= bits_per_digit;
105 *s++ = (n1 >> bit_pos) & ((1 << bits_per_digit) - 1);
106 bit_pos -= bits_per_digit;
111 n0 = (n1 << -bit_pos) & ((1 << bits_per_digit) - 1);
113 bit_pos += BITS_PER_MP_LIMB;
114 *s++ = n0 | (n1 >> bit_pos);
123 /* General case. The base is not a power of 2. Make conversion
124 from least significant end. */
126 /* If udiv_qrnnd only handles divisors with the most significant bit
127 set, prepare BIG_BASE for being a divisor by shifting it to the
128 left exactly enough to set the most significant bit. */
129 #if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
130 count_leading_zeros (normalization_steps, big_base);
131 big_base <<= normalization_steps;
132 #if UDIV_TIME > 2 * UMUL_TIME
133 /* Get the fixed-point approximation to 1/(BIG_BASE << NORMALIZATION_STEPS). */
134 big_base_inverted = __mp_bases[base].big_base_inverted;
138 dig_per_u = __mp_bases[base].chars_per_limb;
139 out_len = ((size_t) msize * BITS_PER_MP_LIMB
140 * __mp_bases[base].chars_per_bit_exactly) + 1;
148 #if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
149 /* If we shifted BIG_BASE above, shift the dividend too, to get
150 the right quotient. We need to do this every loop,
151 since the intermediate quotients are OK, but the quotient from
152 one turn in the loop is going to be the dividend in the
153 next turn, and the dividend needs to be up-shifted. */
154 if (normalization_steps != 0)
156 n0 = mpn_lshift (mptr, mptr, msize, normalization_steps);
158 /* If the shifting gave a carry out limb, store it and
159 increase the length. */
168 /* Divide the number at TP with BIG_BASE to get a quotient and a
169 remainder. The remainder is our new digit in base BIG_BASE. */
184 #if UDIV_TIME > 2 * UMUL_TIME
185 udiv_qrnnd_preinv (mptr[i], n1, n1, n0, big_base, big_base_inverted);
187 udiv_qrnnd (mptr[i], n1, n1, n0, big_base);
191 #if UDIV_NEEDS_NORMALIZATION || UDIV_TIME > 2 * UMUL_TIME
192 /* If we shifted above (at previous UDIV_NEEDS_NORMALIZATION tests)
193 the remainder will be up-shifted here. Compensate. */
194 n1 >>= normalization_steps;
197 /* Convert N1 from BIG_BASE to a string of digits in BASE
198 using single precision operations. */
199 for (i = dig_per_u - 1; i >= 0; i--)
203 if (n1 == 0 && msize == 0)