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author | David Schultz <das@FreeBSD.org> | 2003-03-12 20:18:32 +0000 |
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committer | David Schultz <das@FreeBSD.org> | 2003-03-12 20:18:32 +0000 |
commit | cc36ccd13b36b705dfb09d90e8de63e49734f8d4 (patch) | |
tree | 632bc138392cfc4c37a7e12065afe443d31145eb /contrib/gdtoa/gethex.c | |
download | src-cc36ccd13b36b705dfb09d90e8de63e49734f8d4.tar.gz src-cc36ccd13b36b705dfb09d90e8de63e49734f8d4.zip |
Initial import of David Gay's gdtoa library for conversion betweenvendor/gdtoa/20030305
strings and floating point.
Notes
Notes:
svn path=/vendor/gdtoa/dist/; revision=112158
svn path=/vendor/gdtoa/20030305/; revision=112160; tag=vendor/gdtoa/20030305
Diffstat (limited to 'contrib/gdtoa/gethex.c')
-rw-r--r-- | contrib/gdtoa/gethex.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/contrib/gdtoa/gethex.c b/contrib/gdtoa/gethex.c new file mode 100644 index 000000000000..333f075932c9 --- /dev/null +++ b/contrib/gdtoa/gethex.c @@ -0,0 +1,242 @@ +/**************************************************************** + +The author of this software is David M. Gay. + +Copyright (C) 1998 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 + Bell Laboratories, Room 2C-463 + 600 Mountain Avenue + Murray Hill, NJ 07974-0636 + U.S.A. + dmg@bell-labs.com + */ + +#include "gdtoaimp.h" + + int +#ifdef KR_headers +gethex(sp, fpi, exp, bp, sign) + CONST char **sp; FPI *fpi; Long *exp; Bigint **bp; int sign; +#else +gethex( CONST char **sp, FPI *fpi, Long *exp, Bigint **bp, int sign) +#endif +{ + Bigint *b; + CONST unsigned char *decpt, *s0, *s, *s1; + int esign, havedig, irv, k, n, nbits, up; + ULong L, lostbits, *x; + Long e, e1; + + if (!hexdig['0']) + hexdig_init_D2A(); + havedig = 0; + s0 = *(CONST unsigned char **)sp + 2; + while(s0[havedig] == '0') + havedig++; + s0 += havedig; + s = s0; + decpt = 0; + if (!hexdig[*s]) { + if (*s == '.') { + decpt = ++s; + if (!hexdig[*s]) + goto ret0; + } + else { + ret0: + *sp = (char*)s; + return havedig ? STRTOG_Zero : STRTOG_NoNumber; + } + while(*s == '0') + s++; + havedig = 1; + if (!hexdig[*s]) + goto ret0; + s0 = s; + } + while(hexdig[*s]) + s++; + if (*s == '.' && !decpt) { + decpt = ++s; + while(hexdig[*s]) + s++; + } + e = 0; + if (decpt) + e = -(((Long)(s-decpt)) << 2); + s1 = s; + switch(*s) { + case 'p': + case 'P': + esign = 0; + switch(*++s) { + case '-': + esign = 1; + /* no break */ + case '+': + s++; + } + if ((n = hexdig[*s]) == 0 || n > 0x19) { + s = s1; + break; + } + e1 = n - 0x10; + while((n = hexdig[*++s]) !=0 && n <= 0x19) + e1 = 10*e1 + n - 0x10; + if (esign) + e1 = -e1; + e += e1; + } + *sp = (char*)s; + n = s1 - s0 - 1; + for(k = 0; n > 7; n >>= 1) + k++; + b = Balloc(k); + x = b->x; + n = 0; + L = 0; + while(s1 > s0) { + if (*--s1 == '.') + continue; + if (n == 32) { + *x++ = L; + L = 0; + n = 0; + } + L |= (hexdig[*s1] & 0x0f) << n; + n += 4; + } + *x++ = L; + b->wds = n = x - b->x; + n = 32*n - hi0bits(L); + nbits = fpi->nbits; + lostbits = 0; + x = b->x; + if (n > nbits) { + n -= nbits; + if (any_on(b,n)) { + lostbits = 1; + k = n - 1; + if (x[k>>kshift] & 1 << (k & kmask)) { + lostbits = 2; + if (k > 1 && any_on(b,k-1)) + lostbits = 3; + } + } + rshift(b, n); + e += n; + } + else if (n < nbits) { + n = nbits - n; + b = lshift(b, n); + e -= n; + x = b->x; + } + if (e > fpi->emax) { + ovfl: + Bfree(b); + return STRTOG_Infinite | STRTOG_Overflow | STRTOG_Inexhi; + } + irv = STRTOG_Normal; + if (e < fpi->emin) { + irv = STRTOG_Denormal; + n = fpi->emin - e; + if (n >= nbits) { + switch (fpi->rounding) { + case FPI_Round_near: + if (n == nbits && n < 2 || any_on(b,n-1)) + goto one_bit; + break; + case FPI_Round_up: + if (!sign) + goto one_bit; + break; + case FPI_Round_down: + if (sign) { + one_bit: + *exp = fpi->emin; + x[0] = b->wds = 1; + *bp = b; + return STRTOG_Denormal | STRTOG_Inexhi + | STRTOG_Underflow; + } + } + Bfree(b); + return STRTOG_Zero | STRTOG_Inexlo | STRTOG_Underflow; + } + k = n - 1; + if (lostbits) + lostbits = 1; + else if (k > 0) + lostbits = any_on(b,k); + if (x[k>>kshift] & 1 << (k & kmask)) + lostbits |= 2; + nbits -= n; + rshift(b,n); + e = fpi->emin; + } + if (lostbits) { + up = 0; + switch(fpi->rounding) { + case FPI_Round_zero: + break; + case FPI_Round_near: + if (lostbits & 2 + && (lostbits & 1) | x[0] & 1) + up = 1; + break; + case FPI_Round_up: + up = 1 - sign; + break; + case FPI_Round_down: + up = sign; + } + if (up) { + k = b->wds; + b = increment(b); + x = b->x; + if (b->wds > k + || (n = nbits & kmask) !=0 + && hi0bits(x[k-1]) < 32-n) { + rshift(b,1); + if (++e > fpi->emax) + goto ovfl; + } + else if (irv == STRTOG_Denormal) { + k = nbits - 1; + if (x[k >> kshift] & 1 << (k & kmask)) + irv = STRTOG_Normal; + } + irv |= STRTOG_Inexhi; + } + else + irv |= STRTOG_Inexlo; + } + *bp = b; + *exp = e; + return irv; + } |