| /**************************************************************** |
| |
| 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 |
| { |
| static unsigned char hexdig[256]; /* assume 8-bit bytes */ |
| 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; |
| } |