URL
https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk
Subversion Repositories openrisc_me
[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [packages/] [language/] [c/] [libc/] [stdlib/] [v2_0/] [src/] [strtod.cxx] - Rev 174
Compare with Previous | Blame | View Log
//=========================================================================== // // strtod.cxx // // ISO String to double-precision floating point conversion // //=========================================================================== //####ECOSGPLCOPYRIGHTBEGIN#### // ------------------------------------------- // This file is part of eCos, the Embedded Configurable Operating System. // Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc. // // eCos is free software; you can redistribute it and/or modify it under // the terms of the GNU General Public License as published by the Free // Software Foundation; either version 2 or (at your option) any later version. // // eCos is distributed in the hope that it will be useful, but WITHOUT ANY // WARRANTY; without even the implied warranty of MERCHANTABILITY or // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // // You should have received a copy of the GNU General Public License along // with eCos; if not, write to the Free Software Foundation, Inc., // 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. // // As a special exception, if other files instantiate templates or use macros // or inline functions from this file, or you compile this file and link it // with other works to produce a work based on this file, this file does not // by itself cause the resulting work to be covered by the GNU General Public // License. However the source code for this file must still be made available // in accordance with section (3) of the GNU General Public License. // // This exception does not invalidate any other reasons why a work based on // this file might be covered by the GNU General Public License. // // Alternative licenses for eCos may be arranged by contacting Red Hat, Inc. // at http://sources.redhat.com/ecos/ecos-license/ // ------------------------------------------- //####ECOSGPLCOPYRIGHTEND#### //=========================================================================== //#####DESCRIPTIONBEGIN#### // // Author(s): jlarmour // Contributors: // Date: 2000-04-30 // Purpose: // Description: // Usage: // //####DESCRIPTIONEND#### // //=========================================================================== // CONFIGURATION #include <pkgconf/libc_stdlib.h> // Configuration header // Include strtod()? #if defined(CYGFUN_LIBC_strtod) // INCLUDES #include <cyg/infra/cyg_type.h> // Common type definitions and support #include <cyg/infra/cyg_trac.h> // Tracing support #include <cyg/infra/cyg_ass.h> // Assertion support #include <stddef.h> // NULL, wchar_t and size_t from compiler #include <stdlib.h> // Main header for stdlib functions #include <ctype.h> // isspace() and isdigit() #include <float.h> // DBL_MIN_10_EXP and DBL_MAX_10_EXP #include <math.h> // HUGE_VAL #include <errno.h> // errno // CONSTANTS #define MAXE (DBL_MAX_10_EXP) #define MINE (DBL_MIN_10_EXP) // flags #define SIGN 0x01 #define ESIGN 0x02 #define DECP 0x04 // MACROS #define Ise(c) ((c == 'e') || (c == 'E') || (c == 'd') || (c == 'D')) #define Issign(c) ((c == '-') || (c == '+')) #define Val(c) ((c - '0')) // FUNCTIONS /* * [atw] multiply 64 bit accumulator by 10 and add digit. * The KA/CA way to do this should be to use * a 64-bit integer internally and use "adjust" to * convert it to float at the end of processing. */ static int ten_mul(double *acc, int digit) { /* [atw] Crude, but effective (at least on a KB)... */ *acc *= 10; *acc += digit; return 0; /* no overflow */ } // ten_mul() /* * compute 10**x by successive squaring. */ static const double exp10(unsigned x) { static double powtab[] = {1.0, 10.0, 100.0, 1000.0, 10000.0}; if (x < (sizeof(powtab)/sizeof(double))) return powtab[x]; else if (x & 1) return 10.0 * exp10(x-1); else return exp10(x/2) * exp10(x/2); } // exp10() /* * return (*acc) scaled by 10**dexp. */ static double adjust(double *acc, int dexp, int sign) /* *acc the 64 bit accumulator */ /* dexp decimal exponent */ /* sign sign flag */ { double r; if (dexp > MAXE) { errno = ERANGE; return (sign) ? -HUGE_VAL : HUGE_VAL; } else if (dexp < MINE) { errno = ERANGE; return 0.0; } r = *acc; if (sign) r = -r; if (dexp==0) return r; if (dexp < 0) return r / exp10(abs(dexp)); else return r * exp10(dexp); } // adjust() externC double strtod( const char *nptr, char **endptr ) { const char *start=nptr; double accum = 0.0; int flags = 0; int texp = 0; int e = 0; int conv_done = 0; double retval; CYG_REPORT_FUNCNAMETYPE( "strtod", "returning %f" ); CYG_CHECK_DATA_PTR( nptr, "nptr is an invalid pointer!" ); // endptr is allowed to be NULL, but if it isn't, we check it if (endptr != NULL) CYG_CHECK_DATA_PTR( endptr, "endptr is an invalid pointer!" ); while(isspace(*nptr)) nptr++; if(*nptr == '\0') { /* just leading spaces */ if(endptr != NULL) *endptr = (char *)start; return 0.0; } if(Issign(*nptr)) { if(*nptr == '-') flags = SIGN; if(*++nptr == '\0') { /* "+|-" : should be an error ? */ if(endptr != NULL) *endptr = (char *)start; return 0.0; } } for(; (isdigit(*nptr) || (*nptr == '.')); nptr++) { conv_done = 1; if(*nptr == '.') flags |= DECP; else { if( ten_mul(&accum, Val(*nptr)) ) texp++; if(flags & DECP) texp--; } } if(Ise(*nptr)) { conv_done = 1; if(*++nptr != '\0') /* skip e|E|d|D */ { /* ! ([nptr]xxx[.[yyy]]e) */ while(isspace(*nptr)) nptr++; /* Ansi allows spaces after e */ if(*nptr != '\0') { /* ! ([nptr]xxx[.[yyy]]e[space]) */ if(Issign(*nptr)) if(*nptr++ == '-') flags |= ESIGN; if(*nptr != '\0') { /* ! ([nptr]xxx[.[yyy]]e[nptr]) -- error?? */ for(; isdigit(*nptr); nptr++) if (e < MAXE) /* prevent from grossly overflowing */ e = e*10 + Val(*nptr); /* dont care what comes after this */ if(flags & ESIGN) texp -= e; else texp += e; } } } } if(endptr != NULL) *endptr = (char *)((conv_done) ? nptr : start); retval = adjust(&accum, (int)texp, (int)(flags & SIGN)); CYG_REPORT_RETVAL( retval ); return retval; } // strtod() #endif // if defined(CYGFUN_LIBC_strtod) // EOF strtod.cxx