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[/] [openrisc/] [tags/] [gnu-src/] [newlib-1.18.0/] [newlib-1.18.0-or32-1.0rc1/] [newlib/] [libc/] [stdlib/] [mprec.c] - Rev 345
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/**************************************************************** * * The author of this software is David M. Gay. * * Copyright (c) 1991 by AT&T. * * Permission to use, copy, modify, and distribute this software for any * purpose without fee is hereby granted, provided that this entire notice * is included in all copies of any software which is or includes a copy * or modification of this software and in all copies of the supporting * documentation for such software. * * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED * WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. * ***************************************************************/ /* Please send bug reports to David M. Gay AT&T Bell Laboratories, Room 2C-463 600 Mountain Avenue Murray Hill, NJ 07974-2070 U.S.A. dmg@research.att.com or research!dmg */ /* strtod for IEEE-, VAX-, and IBM-arithmetic machines. * * This strtod returns a nearest machine number to the input decimal * string (or sets errno to ERANGE). With IEEE arithmetic, ties are * broken by the IEEE round-even rule. Otherwise ties are broken by * biased rounding (add half and chop). * * Inspired loosely by William D. Clinger's paper "How to Read Floating * Point Numbers Accurately" [Proc. ACM SIGPLAN '90, pp. 92-101]. * * Modifications: * * 1. We only require IEEE, IBM, or VAX double-precision * arithmetic (not IEEE double-extended). * 2. We get by with floating-point arithmetic in a case that * Clinger missed -- when we're computing d * 10^n * for a small integer d and the integer n is not too * much larger than 22 (the maximum integer k for which * we can represent 10^k exactly), we may be able to * compute (d*10^k) * 10^(e-k) with just one roundoff. * 3. Rather than a bit-at-a-time adjustment of the binary * result in the hard case, we use floating-point * arithmetic to determine the adjustment to within * one bit; only in really hard cases do we need to * compute a second residual. * 4. Because of 3., we don't need a large table of powers of 10 * for ten-to-e (just some small tables, e.g. of 10^k * for 0 <= k <= 22). */ /* * #define IEEE_8087 for IEEE-arithmetic machines where the least * significant byte has the lowest address. * #define IEEE_MC68k for IEEE-arithmetic machines where the most * significant byte has the lowest address. * #define Sudden_Underflow for IEEE-format machines without gradual * underflow (i.e., that flush to zero on underflow). * #define IBM for IBM mainframe-style floating-point arithmetic. * #define VAX for VAX-style floating-point arithmetic. * #define Unsigned_Shifts if >> does treats its left operand as unsigned. * #define No_leftright to omit left-right logic in fast floating-point * computation of dtoa. * #define Check_FLT_ROUNDS if FLT_ROUNDS can assume the values 2 or 3. * #define RND_PRODQUOT to use rnd_prod and rnd_quot (assembly routines * that use extended-precision instructions to compute rounded * products and quotients) with IBM. * #define ROUND_BIASED for IEEE-format with biased rounding. * #define Inaccurate_Divide for IEEE-format with correctly rounded * products but inaccurate quotients, e.g., for Intel i860. * #define Just_16 to store 16 bits per 32-bit long when doing high-precision * integer arithmetic. Whether this speeds things up or slows things * down depends on the machine and the number being converted. */ #include <_ansi.h> #include <stdlib.h> #include <string.h> #include <reent.h> #include "mprec.h" /* This is defined in sys/reent.h as (sizeof (size_t) << 3) now, as in NetBSD. The old value of 15 was wrong and made newlib vulnerable against buffer overrun attacks (CVE-2009-0689), same as other implementations of gdtoa based on BSD code. #define _Kmax 15 */ _Bigint * _DEFUN (Balloc, (ptr, k), struct _reent *ptr _AND int k) { int x; _Bigint *rv ; _REENT_CHECK_MP(ptr); if (_REENT_MP_FREELIST(ptr) == NULL) { /* Allocate a list of pointers to the mprec objects */ _REENT_MP_FREELIST(ptr) = (struct _Bigint **) _calloc_r (ptr, sizeof (struct _Bigint *), _Kmax + 1); if (_REENT_MP_FREELIST(ptr) == NULL) { return NULL; } } if ((rv = _REENT_MP_FREELIST(ptr)[k]) != 0) { _REENT_MP_FREELIST(ptr)[k] = rv->_next; } else { x = 1 << k; /* Allocate an mprec Bigint and stick in in the freelist */ rv = (_Bigint *) _calloc_r (ptr, 1, sizeof (_Bigint) + (x-1) * sizeof(rv->_x)); if (rv == NULL) return NULL; rv->_k = k; rv->_maxwds = x; } rv->_sign = rv->_wds = 0; return rv; } void _DEFUN (Bfree, (ptr, v), struct _reent *ptr _AND _Bigint * v) { _REENT_CHECK_MP(ptr); if (v) { v->_next = _REENT_MP_FREELIST(ptr)[v->_k]; _REENT_MP_FREELIST(ptr)[v->_k] = v; } } _Bigint * _DEFUN (multadd, (ptr, b, m, a), struct _reent *ptr _AND _Bigint * b _AND int m _AND int a) { int i, wds; __ULong *x, y; #ifdef Pack_32 __ULong xi, z; #endif _Bigint *b1; wds = b->_wds; x = b->_x; i = 0; do { #ifdef Pack_32 xi = *x; y = (xi & 0xffff) * m + a; z = (xi >> 16) * m + (y >> 16); a = (int) (z >> 16); *x++ = (z << 16) + (y & 0xffff); #else y = *x * m + a; a = (int) (y >> 16); *x++ = y & 0xffff; #endif } while (++i < wds); if (a) { if (wds >= b->_maxwds) { b1 = Balloc (ptr, b->_k + 1); Bcopy (b1, b); Bfree (ptr, b); b = b1; } b->_x[wds++] = a; b->_wds = wds; } return b; } _Bigint * _DEFUN (s2b, (ptr, s, nd0, nd, y9), struct _reent * ptr _AND _CONST char *s _AND int nd0 _AND int nd _AND __ULong y9) { _Bigint *b; int i, k; __Long x, y; x = (nd + 8) / 9; for (k = 0, y = 1; x > y; y <<= 1, k++); #ifdef Pack_32 b = Balloc (ptr, k); b->_x[0] = y9; b->_wds = 1; #else b = Balloc (ptr, k + 1); b->_x[0] = y9 & 0xffff; b->_wds = (b->_x[1] = y9 >> 16) ? 2 : 1; #endif i = 9; if (9 < nd0) { s += 9; do b = multadd (ptr, b, 10, *s++ - '0'); while (++i < nd0); s++; } else s += 10; for (; i < nd; i++) b = multadd (ptr, b, 10, *s++ - '0'); return b; } int _DEFUN (hi0bits, (x), register __ULong x) { register int k = 0; if (!(x & 0xffff0000)) { k = 16; x <<= 16; } if (!(x & 0xff000000)) { k += 8; x <<= 8; } if (!(x & 0xf0000000)) { k += 4; x <<= 4; } if (!(x & 0xc0000000)) { k += 2; x <<= 2; } if (!(x & 0x80000000)) { k++; if (!(x & 0x40000000)) return 32; } return k; } int _DEFUN (lo0bits, (y), __ULong *y) { register int k; register __ULong x = *y; if (x & 7) { if (x & 1) return 0; if (x & 2) { *y = x >> 1; return 1; } *y = x >> 2; return 2; } k = 0; if (!(x & 0xffff)) { k = 16; x >>= 16; } if (!(x & 0xff)) { k += 8; x >>= 8; } if (!(x & 0xf)) { k += 4; x >>= 4; } if (!(x & 0x3)) { k += 2; x >>= 2; } if (!(x & 1)) { k++; x >>= 1; if (!x & 1) return 32; } *y = x; return k; } _Bigint * _DEFUN (i2b, (ptr, i), struct _reent * ptr _AND int i) { _Bigint *b; b = Balloc (ptr, 1); b->_x[0] = i; b->_wds = 1; return b; } _Bigint * _DEFUN (mult, (ptr, a, b), struct _reent * ptr _AND _Bigint * a _AND _Bigint * b) { _Bigint *c; int k, wa, wb, wc; __ULong carry, y, z; __ULong *x, *xa, *xae, *xb, *xbe, *xc, *xc0; #ifdef Pack_32 __ULong z2; #endif if (a->_wds < b->_wds) { c = a; a = b; b = c; } k = a->_k; wa = a->_wds; wb = b->_wds; wc = wa + wb; if (wc > a->_maxwds) k++; c = Balloc (ptr, k); for (x = c->_x, xa = x + wc; x < xa; x++) *x = 0; xa = a->_x; xae = xa + wa; xb = b->_x; xbe = xb + wb; xc0 = c->_x; #ifdef Pack_32 for (; xb < xbe; xb++, xc0++) { if ((y = *xb & 0xffff) != 0) { x = xa; xc = xc0; carry = 0; do { z = (*x & 0xffff) * y + (*xc & 0xffff) + carry; carry = z >> 16; z2 = (*x++ >> 16) * y + (*xc >> 16) + carry; carry = z2 >> 16; Storeinc (xc, z2, z); } while (x < xae); *xc = carry; } if ((y = *xb >> 16) != 0) { x = xa; xc = xc0; carry = 0; z2 = *xc; do { z = (*x & 0xffff) * y + (*xc >> 16) + carry; carry = z >> 16; Storeinc (xc, z, z2); z2 = (*x++ >> 16) * y + (*xc & 0xffff) + carry; carry = z2 >> 16; } while (x < xae); *xc = z2; } } #else for (; xb < xbe; xc0++) { if (y = *xb++) { x = xa; xc = xc0; carry = 0; do { z = *x++ * y + *xc + carry; carry = z >> 16; *xc++ = z & 0xffff; } while (x < xae); *xc = carry; } } #endif for (xc0 = c->_x, xc = xc0 + wc; wc > 0 && !*--xc; --wc); c->_wds = wc; return c; } _Bigint * _DEFUN (pow5mult, (ptr, b, k), struct _reent * ptr _AND _Bigint * b _AND int k) { _Bigint *b1, *p5, *p51; int i; static _CONST int p05[3] = {5, 25, 125}; if ((i = k & 3) != 0) b = multadd (ptr, b, p05[i - 1], 0); if (!(k >>= 2)) return b; _REENT_CHECK_MP(ptr); if (!(p5 = _REENT_MP_P5S(ptr))) { /* first time */ p5 = _REENT_MP_P5S(ptr) = i2b (ptr, 625); p5->_next = 0; } for (;;) { if (k & 1) { b1 = mult (ptr, b, p5); Bfree (ptr, b); b = b1; } if (!(k >>= 1)) break; if (!(p51 = p5->_next)) { p51 = p5->_next = mult (ptr, p5, p5); p51->_next = 0; } p5 = p51; } return b; } _Bigint * _DEFUN (lshift, (ptr, b, k), struct _reent * ptr _AND _Bigint * b _AND int k) { int i, k1, n, n1; _Bigint *b1; __ULong *x, *x1, *xe, z; #ifdef Pack_32 n = k >> 5; #else n = k >> 4; #endif k1 = b->_k; n1 = n + b->_wds + 1; for (i = b->_maxwds; n1 > i; i <<= 1) k1++; b1 = Balloc (ptr, k1); x1 = b1->_x; for (i = 0; i < n; i++) *x1++ = 0; x = b->_x; xe = x + b->_wds; #ifdef Pack_32 if (k &= 0x1f) { k1 = 32 - k; z = 0; do { *x1++ = *x << k | z; z = *x++ >> k1; } while (x < xe); if ((*x1 = z) != 0) ++n1; } #else if (k &= 0xf) { k1 = 16 - k; z = 0; do { *x1++ = *x << k & 0xffff | z; z = *x++ >> k1; } while (x < xe); if (*x1 = z) ++n1; } #endif else do *x1++ = *x++; while (x < xe); b1->_wds = n1 - 1; Bfree (ptr, b); return b1; } int _DEFUN (cmp, (a, b), _Bigint * a _AND _Bigint * b) { __ULong *xa, *xa0, *xb, *xb0; int i, j; i = a->_wds; j = b->_wds; #ifdef DEBUG if (i > 1 && !a->_x[i - 1]) Bug ("cmp called with a->_x[a->_wds-1] == 0"); if (j > 1 && !b->_x[j - 1]) Bug ("cmp called with b->_x[b->_wds-1] == 0"); #endif if (i -= j) return i; xa0 = a->_x; xa = xa0 + j; xb0 = b->_x; xb = xb0 + j; for (;;) { if (*--xa != *--xb) return *xa < *xb ? -1 : 1; if (xa <= xa0) break; } return 0; } _Bigint * _DEFUN (diff, (ptr, a, b), struct _reent * ptr _AND _Bigint * a _AND _Bigint * b) { _Bigint *c; int i, wa, wb; __Long borrow, y; /* We need signed shifts here. */ __ULong *xa, *xae, *xb, *xbe, *xc; #ifdef Pack_32 __Long z; #endif i = cmp (a, b); if (!i) { c = Balloc (ptr, 0); c->_wds = 1; c->_x[0] = 0; return c; } if (i < 0) { c = a; a = b; b = c; i = 1; } else i = 0; c = Balloc (ptr, a->_k); c->_sign = i; wa = a->_wds; xa = a->_x; xae = xa + wa; wb = b->_wds; xb = b->_x; xbe = xb + wb; xc = c->_x; borrow = 0; #ifdef Pack_32 do { y = (*xa & 0xffff) - (*xb & 0xffff) + borrow; borrow = y >> 16; Sign_Extend (borrow, y); z = (*xa++ >> 16) - (*xb++ >> 16) + borrow; borrow = z >> 16; Sign_Extend (borrow, z); Storeinc (xc, z, y); } while (xb < xbe); while (xa < xae) { y = (*xa & 0xffff) + borrow; borrow = y >> 16; Sign_Extend (borrow, y); z = (*xa++ >> 16) + borrow; borrow = z >> 16; Sign_Extend (borrow, z); Storeinc (xc, z, y); } #else do { y = *xa++ - *xb++ + borrow; borrow = y >> 16; Sign_Extend (borrow, y); *xc++ = y & 0xffff; } while (xb < xbe); while (xa < xae) { y = *xa++ + borrow; borrow = y >> 16; Sign_Extend (borrow, y); *xc++ = y & 0xffff; } #endif while (!*--xc) wa--; c->_wds = wa; return c; } double _DEFUN (ulp, (_x), double _x) { union double_union x, a; register __Long L; x.d = _x; L = (word0 (x) & Exp_mask) - (P - 1) * Exp_msk1; #ifndef Sudden_Underflow if (L > 0) { #endif #ifdef IBM L |= Exp_msk1 >> 4; #endif word0 (a) = L; #ifndef _DOUBLE_IS_32BITS word1 (a) = 0; #endif #ifndef Sudden_Underflow } else { L = -L >> Exp_shift; if (L < Exp_shift) { word0 (a) = 0x80000 >> L; #ifndef _DOUBLE_IS_32BITS word1 (a) = 0; #endif } else { word0 (a) = 0; L -= Exp_shift; #ifndef _DOUBLE_IS_32BITS word1 (a) = L >= 31 ? 1 : 1 << (31 - L); #endif } } #endif return a.d; } double _DEFUN (b2d, (a, e), _Bigint * a _AND int *e) { __ULong *xa, *xa0, w, y, z; int k; union double_union d; #ifdef VAX __ULong d0, d1; #else #define d0 word0(d) #define d1 word1(d) #endif xa0 = a->_x; xa = xa0 + a->_wds; y = *--xa; #ifdef DEBUG if (!y) Bug ("zero y in b2d"); #endif k = hi0bits (y); *e = 32 - k; #ifdef Pack_32 if (k < Ebits) { d0 = Exp_1 | y >> (Ebits - k); w = xa > xa0 ? *--xa : 0; #ifndef _DOUBLE_IS_32BITS d1 = y << ((32 - Ebits) + k) | w >> (Ebits - k); #endif goto ret_d; } z = xa > xa0 ? *--xa : 0; if (k -= Ebits) { d0 = Exp_1 | y << k | z >> (32 - k); y = xa > xa0 ? *--xa : 0; #ifndef _DOUBLE_IS_32BITS d1 = z << k | y >> (32 - k); #endif } else { d0 = Exp_1 | y; #ifndef _DOUBLE_IS_32BITS d1 = z; #endif } #else if (k < Ebits + 16) { z = xa > xa0 ? *--xa : 0; d0 = Exp_1 | y << k - Ebits | z >> Ebits + 16 - k; w = xa > xa0 ? *--xa : 0; y = xa > xa0 ? *--xa : 0; d1 = z << k + 16 - Ebits | w << k - Ebits | y >> 16 + Ebits - k; goto ret_d; } z = xa > xa0 ? *--xa : 0; w = xa > xa0 ? *--xa : 0; k -= Ebits + 16; d0 = Exp_1 | y << k + 16 | z << k | w >> 16 - k; y = xa > xa0 ? *--xa : 0; d1 = w << k + 16 | y << k; #endif ret_d: #ifdef VAX word0 (d) = d0 >> 16 | d0 << 16; word1 (d) = d1 >> 16 | d1 << 16; #else #undef d0 #undef d1 #endif return d.d; } _Bigint * _DEFUN (d2b, (ptr, _d, e, bits), struct _reent * ptr _AND double _d _AND int *e _AND int *bits) { union double_union d; _Bigint *b; int de, i, k; __ULong *x, y, z; #ifdef VAX __ULong d0, d1; #endif d.d = _d; #ifdef VAX d0 = word0 (d) >> 16 | word0 (d) << 16; d1 = word1 (d) >> 16 | word1 (d) << 16; #else #define d0 word0(d) #define d1 word1(d) d.d = _d; #endif #ifdef Pack_32 b = Balloc (ptr, 1); #else b = Balloc (ptr, 2); #endif x = b->_x; z = d0 & Frac_mask; d0 &= 0x7fffffff; /* clear sign bit, which we ignore */ #ifdef Sudden_Underflow de = (int) (d0 >> Exp_shift); #ifndef IBM z |= Exp_msk11; #endif #else if ((de = (int) (d0 >> Exp_shift)) != 0) z |= Exp_msk1; #endif #ifdef Pack_32 #ifndef _DOUBLE_IS_32BITS if (d1) { y = d1; k = lo0bits (&y); if (k) { x[0] = y | z << (32 - k); z >>= k; } else x[0] = y; i = b->_wds = (x[1] = z) ? 2 : 1; } else #endif { #ifdef DEBUG if (!z) Bug ("Zero passed to d2b"); #endif k = lo0bits (&z); x[0] = z; i = b->_wds = 1; #ifndef _DOUBLE_IS_32BITS k += 32; #endif } #else if (d1) { y = d1; k = lo0bits (&y); if (k) if (k >= 16) { x[0] = y | z << 32 - k & 0xffff; x[1] = z >> k - 16 & 0xffff; x[2] = z >> k; i = 2; } else { x[0] = y & 0xffff; x[1] = y >> 16 | z << 16 - k & 0xffff; x[2] = z >> k & 0xffff; x[3] = z >> k + 16; i = 3; } else { x[0] = y & 0xffff; x[1] = y >> 16; x[2] = z & 0xffff; x[3] = z >> 16; i = 3; } } else { #ifdef DEBUG if (!z) Bug ("Zero passed to d2b"); #endif k = lo0bits (&z); if (k >= 16) { x[0] = z; i = 0; } else { x[0] = z & 0xffff; x[1] = z >> 16; i = 1; } k += 32; } while (!x[i]) --i; b->_wds = i + 1; #endif #ifndef Sudden_Underflow if (de) { #endif #ifdef IBM *e = (de - Bias - (P - 1) << 2) + k; *bits = 4 * P + 8 - k - hi0bits (word0 (d) & Frac_mask); #else *e = de - Bias - (P - 1) + k; *bits = P - k; #endif #ifndef Sudden_Underflow } else { *e = de - Bias - (P - 1) + 1 + k; #ifdef Pack_32 *bits = 32 * i - hi0bits (x[i - 1]); #else *bits = (i + 2) * 16 - hi0bits (x[i]); #endif } #endif return b; } #undef d0 #undef d1 double _DEFUN (ratio, (a, b), _Bigint * a _AND _Bigint * b) { union double_union da, db; int k, ka, kb; da.d = b2d (a, &ka); db.d = b2d (b, &kb); #ifdef Pack_32 k = ka - kb + 32 * (a->_wds - b->_wds); #else k = ka - kb + 16 * (a->_wds - b->_wds); #endif #ifdef IBM if (k > 0) { word0 (da) += (k >> 2) * Exp_msk1; if (k &= 3) da.d *= 1 << k; } else { k = -k; word0 (db) += (k >> 2) * Exp_msk1; if (k &= 3) db.d *= 1 << k; } #else if (k > 0) word0 (da) += k * Exp_msk1; else { k = -k; word0 (db) += k * Exp_msk1; } #endif return da.d / db.d; } _CONST double tens[] = { 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, 1e20, 1e21, 1e22, 1e23, 1e24 }; #if !defined(_DOUBLE_IS_32BITS) && !defined(__v800) _CONST double bigtens[] = {1e16, 1e32, 1e64, 1e128, 1e256}; _CONST double tinytens[] = {1e-16, 1e-32, 1e-64, 1e-128, 1e-256}; #else _CONST double bigtens[] = {1e16, 1e32}; _CONST double tinytens[] = {1e-16, 1e-32}; #endif double _DEFUN (_mprec_log10, (dig), int dig) { double v = 1.0; if (dig < 24) return tens[dig]; while (dig > 0) { v *= 10; dig--; } return v; } void _DEFUN (copybits, (c, n, b), __ULong *c _AND int n _AND _Bigint *b) { __ULong *ce, *x, *xe; #ifdef Pack_16 int nw, nw1; #endif ce = c + ((n-1) >> kshift) + 1; x = b->_x; #ifdef Pack_32 xe = x + b->_wds; while(x < xe) *c++ = *x++; #else nw = b->_wds; nw1 = nw & 1; for(xe = x + (nw - nw1); x < xe; x += 2) Storeinc(c, x[1], x[0]); if (nw1) *c++ = *x; #endif while(c < ce) *c++ = 0; } __ULong _DEFUN (any_on, (b, k), _Bigint *b _AND int k) { int n, nwds; __ULong *x, *x0, x1, x2; x = b->_x; nwds = b->_wds; n = k >> kshift; if (n > nwds) n = nwds; else if (n < nwds && (k &= kmask)) { x1 = x2 = x[n]; x1 >>= k; x1 <<= k; if (x1 != x2) return 1; } x0 = x; x += n; while(x > x0) if (*--x) return 1; return 0; }