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Diffstat (limited to 'winsup/mingw/mingwex/gdtoa/dtoa.c')
| -rwxr-xr-x | winsup/mingw/mingwex/gdtoa/dtoa.c | 753 |
1 files changed, 0 insertions, 753 deletions
diff --git a/winsup/mingw/mingwex/gdtoa/dtoa.c b/winsup/mingw/mingwex/gdtoa/dtoa.c deleted file mode 100755 index 9360e80a6..000000000 --- a/winsup/mingw/mingwex/gdtoa/dtoa.c +++ /dev/null @@ -1,753 +0,0 @@ -/**************************************************************** - -The author of this software is David M. Gay. - -Copyright (C) 1998, 1999 by Lucent Technologies -All Rights Reserved - -Permission to use, copy, modify, and distribute this software and -its documentation for any purpose and without fee is hereby -granted, provided that the above copyright notice appear in all -copies and that both that the copyright notice and this -permission notice and warranty disclaimer appear in supporting -documentation, and that the name of Lucent or any of its entities -not be used in advertising or publicity pertaining to -distribution of the software without specific, written prior -permission. - -LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, -INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. -IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY -SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES -WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER -IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, -ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF -THIS SOFTWARE. - -****************************************************************/ - -/* Please send bug reports to David M. Gay (dmg at acm dot org, - * with " at " changed at "@" and " dot " changed to "."). */ - -#include "gdtoaimp.h" - -/* dtoa for IEEE arithmetic (dmg): convert double to ASCII string. - * - * Inspired by "How to Print Floating-Point Numbers Accurately" by - * Guy L. Steele, Jr. and Jon L. White [Proc. ACM SIGPLAN '90, pp. 112-126]. - * - * Modifications: - * 1. Rather than iterating, we use a simple numeric overestimate - * to determine k = floor(log10(d)). We scale relevant - * quantities using O(log2(k)) rather than O(k) multiplications. - * 2. For some modes > 2 (corresponding to ecvt and fcvt), we don't - * try to generate digits strictly left to right. Instead, we - * compute with fewer bits and propagate the carry if necessary - * when rounding the final digit up. This is often faster. - * 3. Under the assumption that input will be rounded nearest, - * mode 0 renders 1e23 as 1e23 rather than 9.999999999999999e22. - * That is, we allow equality in stopping tests when the - * round-nearest rule will give the same floating-point value - * as would satisfaction of the stopping test with strict - * inequality. - * 4. We remove common factors of powers of 2 from relevant - * quantities. - * 5. When converting floating-point integers less than 1e16, - * we use floating-point arithmetic rather than resorting - * to multiple-precision integers. - * 6. When asked to produce fewer than 15 digits, we first try - * to get by with floating-point arithmetic; we resort to - * multiple-precision integer arithmetic only if we cannot - * guarantee that the floating-point calculation has given - * the correctly rounded result. For k requested digits and - * "uniformly" distributed input, the probability is - * something like 10^(k-15) that we must resort to the Long - * calculation. - */ - -#ifdef Honor_FLT_ROUNDS -#define Rounding rounding -#undef Check_FLT_ROUNDS -#define Check_FLT_ROUNDS -#else -#define Rounding Flt_Rounds -#endif - - char * -__dtoa -#ifdef KR_headers - (d, mode, ndigits, decpt, sign, rve) - double d; int mode, ndigits, *decpt, *sign; char **rve; -#else - (double d, int mode, int ndigits, int *decpt, int *sign, char **rve) -#endif -{ - /* Arguments ndigits, decpt, sign are similar to those - of ecvt and fcvt; trailing zeros are suppressed from - the returned string. If not null, *rve is set to point - to the end of the return value. If d is +-Infinity or NaN, - then *decpt is set to 9999. - - mode: - 0 ==> shortest string that yields d when read in - and rounded to nearest. - 1 ==> like 0, but with Steele & White stopping rule; - e.g. with IEEE P754 arithmetic , mode 0 gives - 1e23 whereas mode 1 gives 9.999999999999999e22. - 2 ==> max(1,ndigits) significant digits. This gives a - return value similar to that of ecvt, except - that trailing zeros are suppressed. - 3 ==> through ndigits past the decimal point. This - gives a return value similar to that from fcvt, - except that trailing zeros are suppressed, and - ndigits can be negative. - 4,5 ==> similar to 2 and 3, respectively, but (in - round-nearest mode) with the tests of mode 0 to - possibly return a shorter string that rounds to d. - With IEEE arithmetic and compilation with - -DHonor_FLT_ROUNDS, modes 4 and 5 behave the same - as modes 2 and 3 when FLT_ROUNDS != 1. - 6-9 ==> Debugging modes similar to mode - 4: don't try - fast floating-point estimate (if applicable). - - Values of mode other than 0-9 are treated as mode 0. - - Sufficient space is allocated to the return value - to hold the suppressed trailing zeros. - */ - - int bbits, b2, b5, be, dig, i, ieps, ilim = 0, ilim0, ilim1 = 0, - j, j1, k, k0, k_check, leftright, m2, m5, s2, s5, - spec_case, try_quick; - Long L; -#ifndef Sudden_Underflow - int denorm; - ULong x; -#endif - Bigint *b, *b1, *delta, *mlo, *mhi, *S; - double d2, ds, eps; - char *s, *s0; -#ifdef Honor_FLT_ROUNDS - int rounding; -#endif -#ifdef SET_INEXACT - int inexact, oldinexact; -#endif - -#ifndef MULTIPLE_THREADS - if (dtoa_result) { - __freedtoa(dtoa_result); - dtoa_result = 0; - } -#endif - - if (word0(d) & Sign_bit) { - /* set sign for everything, including 0's and NaNs */ - *sign = 1; - word0(d) &= ~Sign_bit; /* clear sign bit */ - } - else - *sign = 0; - -#if defined(IEEE_Arith) + defined(VAX) -#ifdef IEEE_Arith - if ((word0(d) & Exp_mask) == Exp_mask) -#else - if (word0(d) == 0x8000) -#endif - { - /* Infinity or NaN */ - *decpt = 9999; -#ifdef IEEE_Arith - if (!word1(d) && !(word0(d) & 0xfffff)) - return nrv_alloc("Infinity", rve, 8); -#endif - return nrv_alloc("NaN", rve, 3); - } -#endif -#ifdef IBM - dval(d) += 0; /* normalize */ -#endif - if (!dval(d)) { - *decpt = 1; - return nrv_alloc("0", rve, 1); - } - -#ifdef SET_INEXACT - try_quick = oldinexact = get_inexact(); - inexact = 1; -#endif -#ifdef Honor_FLT_ROUNDS - if ((rounding = Flt_Rounds) >= 2) { - if (*sign) - rounding = rounding == 2 ? 0 : 2; - else - if (rounding != 2) - rounding = 0; - } -#endif - - b = d2b(dval(d), &be, &bbits); -#ifdef Sudden_Underflow - i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1)); -#else - if (( i = (int)(word0(d) >> Exp_shift1 & (Exp_mask>>Exp_shift1)) )!=0) { -#endif - dval(d2) = dval(d); - word0(d2) &= Frac_mask1; - word0(d2) |= Exp_11; -#ifdef IBM - if (( j = 11 - hi0bits(word0(d2) & Frac_mask) )!=0) - dval(d2) /= 1 << j; -#endif - - /* log(x) ~=~ log(1.5) + (x-1.5)/1.5 - * log10(x) = log(x) / log(10) - * ~=~ log(1.5)/log(10) + (x-1.5)/(1.5*log(10)) - * log10(d) = (i-Bias)*log(2)/log(10) + log10(d2) - * - * This suggests computing an approximation k to log10(d) by - * - * k = (i - Bias)*0.301029995663981 - * + ( (d2-1.5)*0.289529654602168 + 0.176091259055681 ); - * - * We want k to be too large rather than too small. - * The error in the first-order Taylor series approximation - * is in our favor, so we just round up the constant enough - * to compensate for any error in the multiplication of - * (i - Bias) by 0.301029995663981; since |i - Bias| <= 1077, - * and 1077 * 0.30103 * 2^-52 ~=~ 7.2e-14, - * adding 1e-13 to the constant term more than suffices. - * Hence we adjust the constant term to 0.1760912590558. - * (We could get a more accurate k by invoking log10, - * but this is probably not worthwhile.) - */ - - i -= Bias; -#ifdef IBM - i <<= 2; - i += j; -#endif -#ifndef Sudden_Underflow - denorm = 0; - } - else { - /* d is denormalized */ - - i = bbits + be + (Bias + (P-1) - 1); - x = i > 32 ? word0(d) << (64 - i) | word1(d) >> (i - 32) - : word1(d) << (32 - i); - dval(d2) = x; - word0(d2) -= 31*Exp_msk1; /* adjust exponent */ - i -= (Bias + (P-1) - 1) + 1; - denorm = 1; - } -#endif - ds = (dval(d2)-1.5)*0.289529654602168 + 0.1760912590558 + i*0.301029995663981; - k = (int)ds; - if (ds < 0. && ds != k) - k--; /* want k = floor(ds) */ - k_check = 1; - if (k >= 0 && k <= Ten_pmax) { - if (dval(d) < tens[k]) - k--; - k_check = 0; - } - j = bbits - i - 1; - if (j >= 0) { - b2 = 0; - s2 = j; - } - else { - b2 = -j; - s2 = 0; - } - if (k >= 0) { - b5 = 0; - s5 = k; - s2 += k; - } - else { - b2 -= k; - b5 = -k; - s5 = 0; - } - if (mode < 0 || mode > 9) - mode = 0; - -#ifndef SET_INEXACT -#ifdef Check_FLT_ROUNDS - try_quick = Rounding == 1; -#else - try_quick = 1; -#endif -#endif /*SET_INEXACT*/ - - if (mode > 5) { - mode -= 4; - try_quick = 0; - } - leftright = 1; - switch(mode) { - case 0: - case 1: - ilim = ilim1 = -1; - i = 18; - ndigits = 0; - break; - case 2: - leftright = 0; - /* no break */ - case 4: - if (ndigits <= 0) - ndigits = 1; - ilim = ilim1 = i = ndigits; - break; - case 3: - leftright = 0; - /* no break */ - case 5: - i = ndigits + k + 1; - ilim = i; - ilim1 = i - 1; - if (i <= 0) - i = 1; - } - s = s0 = rv_alloc(i); - -#ifdef Honor_FLT_ROUNDS - if (mode > 1 && rounding != 1) - leftright = 0; -#endif - - if (ilim >= 0 && ilim <= Quick_max && try_quick) { - - /* Try to get by with floating-point arithmetic. */ - - i = 0; - dval(d2) = dval(d); - k0 = k; - ilim0 = ilim; - ieps = 2; /* conservative */ - if (k > 0) { - ds = tens[k&0xf]; - j = k >> 4; - if (j & Bletch) { - /* prevent overflows */ - j &= Bletch - 1; - dval(d) /= bigtens[n_bigtens-1]; - ieps++; - } - for(; j; j >>= 1, i++) - if (j & 1) { - ieps++; - ds *= bigtens[i]; - } - dval(d) /= ds; - } - else if (( j1 = -k )!=0) { - dval(d) *= tens[j1 & 0xf]; - for(j = j1 >> 4; j; j >>= 1, i++) - if (j & 1) { - ieps++; - dval(d) *= bigtens[i]; - } - } - if (k_check && dval(d) < 1. && ilim > 0) { - if (ilim1 <= 0) - goto fast_failed; - ilim = ilim1; - k--; - dval(d) *= 10.; - ieps++; - } - dval(eps) = ieps*dval(d) + 7.; - word0(eps) -= (P-1)*Exp_msk1; - if (ilim == 0) { - S = mhi = 0; - dval(d) -= 5.; - if (dval(d) > dval(eps)) - goto one_digit; - if (dval(d) < -dval(eps)) - goto no_digits; - goto fast_failed; - } -#ifndef No_leftright - if (leftright) { - /* Use Steele & White method of only - * generating digits needed. - */ - dval(eps) = 0.5/tens[ilim-1] - dval(eps); - for(i = 0;;) { - L = dval(d); - dval(d) -= L; - *s++ = '0' + (int)L; - if (dval(d) < dval(eps)) - goto ret1; - if (1. - dval(d) < dval(eps)) - goto bump_up; - if (++i >= ilim) - break; - dval(eps) *= 10.; - dval(d) *= 10.; - } - } - else { -#endif - /* Generate ilim digits, then fix them up. */ - dval(eps) *= tens[ilim-1]; - for(i = 1;; i++, dval(d) *= 10.) { - L = (Long)(dval(d)); - if (!(dval(d) -= L)) - ilim = i; - *s++ = '0' + (int)L; - if (i == ilim) { - if (dval(d) > 0.5 + dval(eps)) - goto bump_up; - else if (dval(d) < 0.5 - dval(eps)) { - while(*--s == '0'); - s++; - goto ret1; - } - break; - } - } -#ifndef No_leftright - } -#endif - fast_failed: - s = s0; - dval(d) = dval(d2); - k = k0; - ilim = ilim0; - } - - /* Do we have a "small" integer? */ - - if (be >= 0 && k <= Int_max) { - /* Yes. */ - ds = tens[k]; - if (ndigits < 0 && ilim <= 0) { - S = mhi = 0; - if (ilim < 0 || dval(d) <= 5*ds) - goto no_digits; - goto one_digit; - } - for(i = 1;; i++, dval(d) *= 10.) { - L = (Long)(dval(d) / ds); - dval(d) -= L*ds; -#ifdef Check_FLT_ROUNDS - /* If FLT_ROUNDS == 2, L will usually be high by 1 */ - if (dval(d) < 0) { - L--; - dval(d) += ds; - } -#endif - *s++ = '0' + (int)L; - if (!dval(d)) { -#ifdef SET_INEXACT - inexact = 0; -#endif - break; - } - if (i == ilim) { -#ifdef Honor_FLT_ROUNDS - if (mode > 1) - switch(rounding) { - case 0: goto ret1; - case 2: goto bump_up; - } -#endif - dval(d) += dval(d); - if (dval(d) > ds || (dval(d) == ds && L & 1)) { - bump_up: - while(*--s == '9') - if (s == s0) { - k++; - *s = '0'; - break; - } - ++*s++; - } - break; - } - } - goto ret1; - } - - m2 = b2; - m5 = b5; - mhi = mlo = 0; - if (leftright) { - i = -#ifndef Sudden_Underflow - denorm ? be + (Bias + (P-1) - 1 + 1) : -#endif -#ifdef IBM - 1 + 4*P - 3 - bbits + ((bbits + be - 1) & 3); -#else - 1 + P - bbits; -#endif - b2 += i; - s2 += i; - mhi = i2b(1); - } - if (m2 > 0 && s2 > 0) { - i = m2 < s2 ? m2 : s2; - b2 -= i; - m2 -= i; - s2 -= i; - } - if (b5 > 0) { - if (leftright) { - if (m5 > 0) { - mhi = pow5mult(mhi, m5); - b1 = mult(mhi, b); - Bfree(b); - b = b1; - } - if (( j = b5 - m5 )!=0) - b = pow5mult(b, j); - } - else - b = pow5mult(b, b5); - } - S = i2b(1); - if (s5 > 0) - S = pow5mult(S, s5); - - /* Check for special case that d is a normalized power of 2. */ - - spec_case = 0; - if ((mode < 2 || leftright) -#ifdef Honor_FLT_ROUNDS - && rounding == 1 -#endif - ) { - if (!word1(d) && !(word0(d) & Bndry_mask) -#ifndef Sudden_Underflow - && word0(d) & (Exp_mask & ~Exp_msk1) -#endif - ) { - /* The special case */ - b2 += Log2P; - s2 += Log2P; - spec_case = 1; - } - } - - /* Arrange for convenient computation of quotients: - * shift left if necessary so divisor has 4 leading 0 bits. - * - * Perhaps we should just compute leading 28 bits of S once - * and for all and pass them and a shift to quorem, so it - * can do shifts and ors to compute the numerator for q. - */ -#ifdef Pack_32 - if (( i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0x1f )!=0) - i = 32 - i; -#else - if (( i = ((s5 ? 32 - hi0bits(S->x[S->wds-1]) : 1) + s2) & 0xf )!=0) - i = 16 - i; -#endif - if (i > 4) { - i -= 4; - b2 += i; - m2 += i; - s2 += i; - } - else if (i < 4) { - i += 28; - b2 += i; - m2 += i; - s2 += i; - } - if (b2 > 0) - b = lshift(b, b2); - if (s2 > 0) - S = lshift(S, s2); - if (k_check) { - if (cmp(b,S) < 0) { - k--; - b = multadd(b, 10, 0); /* we botched the k estimate */ - if (leftright) - mhi = multadd(mhi, 10, 0); - ilim = ilim1; - } - } - if (ilim <= 0 && (mode == 3 || mode == 5)) { - if (ilim < 0 || cmp(b,S = multadd(S,5,0)) <= 0) { - /* no digits, fcvt style */ - no_digits: - k = -1 - ndigits; - goto ret; - } - one_digit: - *s++ = '1'; - k++; - goto ret; - } - if (leftright) { - if (m2 > 0) - mhi = lshift(mhi, m2); - - /* Compute mlo -- check for special case - * that d is a normalized power of 2. - */ - - mlo = mhi; - if (spec_case) { - mhi = Balloc(mhi->k); - Bcopy(mhi, mlo); - mhi = lshift(mhi, Log2P); - } - - for(i = 1;;i++) { - dig = quorem(b,S) + '0'; - /* Do we yet have the shortest decimal string - * that will round to d? - */ - j = cmp(b, mlo); - delta = diff(S, mhi); - j1 = delta->sign ? 1 : cmp(b, delta); - Bfree(delta); -#ifndef ROUND_BIASED - if (j1 == 0 && mode != 1 && !(word1(d) & 1) -#ifdef Honor_FLT_ROUNDS - && rounding >= 1 -#endif - ) { - if (dig == '9') - goto round_9_up; - if (j > 0) - dig++; -#ifdef SET_INEXACT - else if (!b->x[0] && b->wds <= 1) - inexact = 0; -#endif - *s++ = dig; - goto ret; - } -#endif - if (j < 0 || (j == 0 && mode != 1 -#ifndef ROUND_BIASED - && !(word1(d) & 1) -#endif - )) { - if (!b->x[0] && b->wds <= 1) { -#ifdef SET_INEXACT - inexact = 0; -#endif - goto accept_dig; - } -#ifdef Honor_FLT_ROUNDS - if (mode > 1) - switch(rounding) { - case 0: goto accept_dig; - case 2: goto keep_dig; - } -#endif /*Honor_FLT_ROUNDS*/ - if (j1 > 0) { - b = lshift(b, 1); - j1 = cmp(b, S); - if ((j1 > 0 || (j1 == 0 && dig & 1)) - && dig++ == '9') - goto round_9_up; - } - accept_dig: - *s++ = dig; - goto ret; - } - if (j1 > 0) { -#ifdef Honor_FLT_ROUNDS - if (!rounding) - goto accept_dig; -#endif - if (dig == '9') { /* possible if i == 1 */ - round_9_up: - *s++ = '9'; - goto roundoff; - } - *s++ = dig + 1; - goto ret; - } -#ifdef Honor_FLT_ROUNDS - keep_dig: -#endif - *s++ = dig; - if (i == ilim) - break; - b = multadd(b, 10, 0); - if (mlo == mhi) - mlo = mhi = multadd(mhi, 10, 0); - else { - mlo = multadd(mlo, 10, 0); - mhi = multadd(mhi, 10, 0); - } - } - } - else - for(i = 1;; i++) { - *s++ = dig = quorem(b,S) + '0'; - if (!b->x[0] && b->wds <= 1) { -#ifdef SET_INEXACT - inexact = 0; -#endif - goto ret; - } - if (i >= ilim) - break; - b = multadd(b, 10, 0); - } - - /* Round off last digit */ - -#ifdef Honor_FLT_ROUNDS - switch(rounding) { - case 0: goto trimzeros; - case 2: goto roundoff; - } -#endif - b = lshift(b, 1); - j = cmp(b, S); - if (j > 0 || (j == 0 && dig & 1)) { - roundoff: - while(*--s == '9') - if (s == s0) { - k++; - *s++ = '1'; - goto ret; - } - ++*s++; - } - else { - // trimzeros: - while(*--s == '0'); - s++; - } - ret: - Bfree(S); - if (mhi) { - if (mlo && mlo != mhi) - Bfree(mlo); - Bfree(mhi); - } - ret1: -#ifdef SET_INEXACT - if (inexact) { - if (!oldinexact) { - word0(d) = Exp_1 + (70 << Exp_shift); - word1(d) = 0; - dval(d) += 1.; - } - } - else if (!oldinexact) - clear_inexact(); -#endif - Bfree(b); - *s = 0; - *decpt = k + 1; - if (rve) - *rve = s; - return s0; - } |