diff options
| -rw-r--r-- | gas/ChangeLog | 6 | ||||
| -rw-r--r-- | gas/atof-generic.c | 938 |
2 files changed, 503 insertions, 441 deletions
diff --git a/gas/ChangeLog b/gas/ChangeLog index 2a209b6..268ccfd 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,9 @@ +Thu Jan 27 18:14:19 1994 Ken Raeburn (raeburn@cujo.cygnus.com) + + * atof-generic.c: Some reformatting. + (atof_generic): Be careful when mixing signed/unsigned values of + different sizes. + Thu Jan 27 16:43:51 1994 Ian Lance Taylor (ian@tweedledumb.cygnus.com) * read.c (lex_type): No longer make '{' a valid character for diff --git a/gas/atof-generic.c b/gas/atof-generic.c index 198e980..b55945a 100644 --- a/gas/atof-generic.c +++ b/gas/atof-generic.c @@ -1,18 +1,18 @@ /* atof_generic.c - turn a string of digits into a Flonum Copyright (C) 1987, 1990, 1991, 1992 Free Software Foundation, Inc. - + This file is part of GAS, the GNU Assembler. - + GAS 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. - + GAS 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 GAS; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ @@ -30,12 +30,12 @@ #endif #endif -#ifdef USG -#define bzero(s,n) memset(s,0,n) +#ifndef FALSE +#define FALSE (0) +#endif +#ifndef TRUE +#define TRUE (1) #endif - -/* #define FALSE (0) */ -/* #define TRUE (1) */ /***********************************************************************\ * * @@ -49,19 +49,19 @@ * uses base (radix) 2 * * this machine uses 2's complement binary integers * * target flonums use " " " " * - * target flonums exponents fit in a long * + * target flonums exponents fit in a long * * * \***********************************************************************/ /* - + Syntax: - + <flonum> ::= <optional-sign> <decimal-number> <optional-exponent> <optional-sign> ::= '+' | '-' | {empty} <decimal-number> ::= <integer> - | <integer> <radix-character> - | <integer> <radix-character> <integer> + | <integer> <radix-character> + | <integer> <radix-character> <integer> | <radix-character> <integer> <optional-exponent> ::= {empty} @@ -71,450 +71,506 @@ <digit> ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' <exponent-character> ::= {one character from "string_of_decimal_exponent_marks"} <radix-character> ::= {one character from "string_of_decimal_marks"} - + */ -int /* 0 if OK */ - atof_generic ( - address_of_string_pointer, /* return pointer to just - AFTER number we read. */ - string_of_decimal_marks, /* At most one per number. */ - string_of_decimal_exponent_marks, - address_of_generic_floating_point_number) -char **address_of_string_pointer; -const char *string_of_decimal_marks; -const char *string_of_decimal_exponent_marks; -FLONUM_TYPE *address_of_generic_floating_point_number; +int +atof_generic (address_of_string_pointer, + string_of_decimal_marks, + string_of_decimal_exponent_marks, + address_of_generic_floating_point_number) + /* return pointer to just AFTER number we read. */ + char **address_of_string_pointer; + /* At most one per number. */ + const char *string_of_decimal_marks; + const char *string_of_decimal_exponent_marks; + FLONUM_TYPE *address_of_generic_floating_point_number; { - int return_value; /* 0 means OK. */ - char * first_digit; - /* char *last_digit; JF unused */ - int number_of_digits_before_decimal; - int number_of_digits_after_decimal; - long decimal_exponent; - int number_of_digits_available; - char digits_sign_char; - - /* - * Scan the input string, abstracting (1)digits (2)decimal mark (3) exponent. - * It would be simpler to modify the string, but we don't; just to be nice - * to caller. - * We need to know how many digits we have, so we can allocate space for - * the digits' value. - */ - - char *p; - char c; - int seen_significant_digit; - - first_digit = *address_of_string_pointer; - c = *first_digit; - - if (c == '-' || c == '+') { - digits_sign_char = c; - first_digit++; - } else - digits_sign_char = '+'; - - if ((first_digit[0] == 'n' || first_digit[0] == 'N') - && (first_digit[1] == 'a' || first_digit[1] == 'A') - && (first_digit[2] == 'n' || first_digit[2] == 'N')) { - address_of_generic_floating_point_number->sign = 0; - address_of_generic_floating_point_number->exponent = 0; - address_of_generic_floating_point_number->leader = - address_of_generic_floating_point_number->low; - *address_of_string_pointer = first_digit + 3; - return(0); + int return_value; /* 0 means OK. */ + char *first_digit; + /* char *last_digit; JF unused */ + int number_of_digits_before_decimal; + int number_of_digits_after_decimal; + long decimal_exponent; + int number_of_digits_available; + char digits_sign_char; + + /* + * Scan the input string, abstracting (1)digits (2)decimal mark (3) exponent. + * It would be simpler to modify the string, but we don't; just to be nice + * to caller. + * We need to know how many digits we have, so we can allocate space for + * the digits' value. + */ + + char *p; + char c; + int seen_significant_digit; + + first_digit = *address_of_string_pointer; + c = *first_digit; + + if (c == '-' || c == '+') + { + digits_sign_char = c; + first_digit++; + } + else + digits_sign_char = '+'; + + if ((first_digit[0] == 'n' || first_digit[0] == 'N') + && (first_digit[1] == 'a' || first_digit[1] == 'A') + && (first_digit[2] == 'n' || first_digit[2] == 'N')) + { + address_of_generic_floating_point_number->sign = 0; + address_of_generic_floating_point_number->exponent = 0; + address_of_generic_floating_point_number->leader = + address_of_generic_floating_point_number->low; + *address_of_string_pointer = first_digit + 3; + return 0; + } + + if ((first_digit[0] == 'i' || first_digit[0] == 'I') + && (first_digit[1] == 'n' || first_digit[1] == 'N') + && (first_digit[2] == 'f' || first_digit[2] == 'F')) + { + address_of_generic_floating_point_number->sign = + digits_sign_char == '+' ? 'P' : 'N'; + address_of_generic_floating_point_number->exponent = 0; + address_of_generic_floating_point_number->leader = + address_of_generic_floating_point_number->low; + + if ((first_digit[3] == 'i' + || first_digit[3] == 'I') + && (first_digit[4] == 'n' + || first_digit[4] == 'N') + && (first_digit[5] == 'i' + || first_digit[5] == 'I') + && (first_digit[6] == 't' + || first_digit[6] == 'T') + && (first_digit[7] == 'y' + || first_digit[7] == 'Y')) + { + *address_of_string_pointer = first_digit + 8; } - - if ((first_digit[0] == 'i' || first_digit[0] == 'I') - && (first_digit[1] == 'n' || first_digit[1] == 'N') - && (first_digit[2] == 'f' || first_digit[2] == 'F')) { - address_of_generic_floating_point_number->sign = - digits_sign_char == '+' ? 'P' : 'N'; - address_of_generic_floating_point_number->exponent = 0; - address_of_generic_floating_point_number->leader = - address_of_generic_floating_point_number->low; - - if ((first_digit[3] == 'i' - || first_digit[3] == 'I') - && (first_digit[4] == 'n' - || first_digit[4] == 'N') - && (first_digit[5] == 'i' - || first_digit[5] == 'I') - && (first_digit[6] == 't' - || first_digit[6] == 'T') - && (first_digit[7] == 'y' - || first_digit[7] == 'Y')) { - *address_of_string_pointer = first_digit + 8; - } else { - *address_of_string_pointer = first_digit + 3; - } - return(0); + else + { + *address_of_string_pointer = first_digit + 3; } - - number_of_digits_before_decimal = 0; - number_of_digits_after_decimal = 0; - decimal_exponent = 0; - seen_significant_digit = 0; - for (p = first_digit; (((c = * p) != '\0') - && (!c || ! strchr(string_of_decimal_marks, c)) - && (!c || !strchr(string_of_decimal_exponent_marks, c))); - p++) { - if (isdigit(c)) { - if (seen_significant_digit || c > '0') { - ++number_of_digits_before_decimal; - seen_significant_digit = 1; - } else { - first_digit++; - } - } else { - break; /* p -> char after pre-decimal digits. */ - } - } /* For each digit before decimal mark. */ - + return 0; + } + + number_of_digits_before_decimal = 0; + number_of_digits_after_decimal = 0; + decimal_exponent = 0; + seen_significant_digit = 0; + for (p = first_digit; + (((c = *p) != '\0') + && (!c || !strchr (string_of_decimal_marks, c)) + && (!c || !strchr (string_of_decimal_exponent_marks, c))); + p++) + { + if (isdigit (c)) + { + if (seen_significant_digit || c > '0') + { + ++number_of_digits_before_decimal; + seen_significant_digit = 1; + } + else + { + first_digit++; + } + } + else + { + break; /* p -> char after pre-decimal digits. */ + } + } /* For each digit before decimal mark. */ + #ifndef OLD_FLOAT_READS - /* Ignore trailing 0's after the decimal point. The original code here - * (ifdef'd out) does not do this, and numbers like - * 4.29496729600000000000e+09 (2**31) - * come out inexact for some reason related to length of the digit - * string. - */ - if (c && strchr(string_of_decimal_marks, c)) { - int zeros = 0; /* Length of current string of zeros */ - - for (p++; (c = *p) && isdigit(c); p++) { - if (c == '0') { - zeros++; - } else { - number_of_digits_after_decimal += 1 + zeros; - zeros = 0; - } - } + /* Ignore trailing 0's after the decimal point. The original code here + * (ifdef'd out) does not do this, and numbers like + * 4.29496729600000000000e+09 (2**31) + * come out inexact for some reason related to length of the digit + * string. + */ + if (c && strchr (string_of_decimal_marks, c)) + { + int zeros = 0; /* Length of current string of zeros */ + + for (p++; (c = *p) && isdigit (c); p++) + { + if (c == '0') + { + zeros++; + } + else + { + number_of_digits_after_decimal += 1 + zeros; + zeros = 0; + } } + } #else - if (c && strchr(string_of_decimal_marks, c)) { - for (p++; (((c = *p) != '\0') - && (!c || !strchr(string_of_decimal_exponent_marks, c))); - p++) { - if (isdigit(c)) { - number_of_digits_after_decimal++; /* This may be retracted below. */ - if (/* seen_significant_digit || */ c > '0') { - seen_significant_digit = TRUE; - } - } else { - if (!seen_significant_digit) { - number_of_digits_after_decimal = 0; - } - break; - } - } /* For each digit after decimal mark. */ - } - - while (number_of_digits_after_decimal && first_digit[number_of_digits_before_decimal - + number_of_digits_after_decimal] == '0') - --number_of_digits_after_decimal; - /* last_digit = p; JF unused */ -#endif - - if (c && strchr(string_of_decimal_exponent_marks, c) ) { - char digits_exponent_sign_char; - - c = *++p; - if (c && strchr ("+-",c)) { - digits_exponent_sign_char = c; - c = *++p; - } else { - digits_exponent_sign_char = '+'; - } - - for ( ; (c); c = *++p) { - if (isdigit(c)) { - decimal_exponent = decimal_exponent * 10 + c - '0'; - /* - * BUG! If we overflow here, we lose! - */ - } else { - break; - } + if (c && strchr (string_of_decimal_marks, c)) + { + for (p++; + (((c = *p) != '\0') + && (!c || !strchr (string_of_decimal_exponent_marks, c))); + p++) + { + if (isdigit (c)) + { + /* This may be retracted below. */ + number_of_digits_after_decimal++; + + if ( /* seen_significant_digit || */ c > '0') + { + seen_significant_digit = TRUE; } - - if (digits_exponent_sign_char == '-') { - decimal_exponent = -decimal_exponent; + } + else + { + if (!seen_significant_digit) + { + number_of_digits_after_decimal = 0; } + break; + } + } /* For each digit after decimal mark. */ + } + + while (number_of_digits_after_decimal + && first_digit[number_of_digits_before_decimal + + number_of_digits_after_decimal] == '0') + --number_of_digits_after_decimal; +#endif + + if (c && strchr (string_of_decimal_exponent_marks, c)) + { + char digits_exponent_sign_char; + + c = *++p; + if (c && strchr ("+-", c)) + { + digits_exponent_sign_char = c; + c = *++p; + } + else + { + digits_exponent_sign_char = '+'; } - - *address_of_string_pointer = p; - - - - number_of_digits_available = - number_of_digits_before_decimal + number_of_digits_after_decimal; - return_value = 0; - if (number_of_digits_available == 0) { - address_of_generic_floating_point_number->exponent = 0; /* Not strictly necessary */ - address_of_generic_floating_point_number->leader - = -1 + address_of_generic_floating_point_number->low; - address_of_generic_floating_point_number->sign = digits_sign_char; - /* We have just concocted (+/-)0.0E0 */ - - } else { - int count; /* Number of useful digits left to scan. */ - - LITTLENUM_TYPE *digits_binary_low; - int precision; - int maximum_useful_digits; - int number_of_digits_to_use; - int more_than_enough_bits_for_digits; - int more_than_enough_littlenums_for_digits; - int size_of_digits_in_littlenums; - int size_of_digits_in_chars; - FLONUM_TYPE power_of_10_flonum; - FLONUM_TYPE digits_flonum; - - precision = (address_of_generic_floating_point_number->high - - address_of_generic_floating_point_number->low - + 1); /* Number of destination littlenums. */ - - /* Includes guard bits (two littlenums worth) */ - maximum_useful_digits = (((double) (precision - 2)) - * ((double) (LITTLENUM_NUMBER_OF_BITS)) - / (LOG_TO_BASE_2_OF_10)) - + 2; /* 2 :: guard digits. */ - - if (number_of_digits_available > maximum_useful_digits) { - number_of_digits_to_use = maximum_useful_digits; - } else { - number_of_digits_to_use = number_of_digits_available; + + for (; (c); c = *++p) + { + if (isdigit (c)) + { + decimal_exponent = decimal_exponent * 10 + c - '0'; + /* + * BUG! If we overflow here, we lose! + */ + } + else + { + break; + } + } + + if (digits_exponent_sign_char == '-') + { + decimal_exponent = -decimal_exponent; + } + } + + *address_of_string_pointer = p; + + + + number_of_digits_available = + number_of_digits_before_decimal + number_of_digits_after_decimal; + return_value = 0; + if (number_of_digits_available == 0) + { + address_of_generic_floating_point_number->exponent = 0; /* Not strictly necessary */ + address_of_generic_floating_point_number->leader + = -1 + address_of_generic_floating_point_number->low; + address_of_generic_floating_point_number->sign = digits_sign_char; + /* We have just concocted (+/-)0.0E0 */ + + } + else + { + int count; /* Number of useful digits left to scan. */ + + LITTLENUM_TYPE *digits_binary_low; + unsigned int precision; + unsigned int maximum_useful_digits; + unsigned int number_of_digits_to_use; + unsigned int more_than_enough_bits_for_digits; + unsigned int more_than_enough_littlenums_for_digits; + unsigned int size_of_digits_in_littlenums; + unsigned int size_of_digits_in_chars; + FLONUM_TYPE power_of_10_flonum; + FLONUM_TYPE digits_flonum; + + precision = (address_of_generic_floating_point_number->high + - address_of_generic_floating_point_number->low + + 1); /* Number of destination littlenums. */ + + /* Includes guard bits (two littlenums worth) */ + maximum_useful_digits = (((double) (precision - 2)) + * ((double) (LITTLENUM_NUMBER_OF_BITS)) + / (LOG_TO_BASE_2_OF_10)) + + 2; /* 2 :: guard digits. */ + + if (number_of_digits_available > maximum_useful_digits) + { + number_of_digits_to_use = maximum_useful_digits; + } + else + { + number_of_digits_to_use = number_of_digits_available; + } + + /* Cast these to SIGNED LONG first, otherwise, on systems with + LONG wider than INT (such as Alpha OSF/1), unsignedness may + cause unexpected results. */ + decimal_exponent += ((long) number_of_digits_before_decimal + - (long) number_of_digits_to_use); + + more_than_enough_bits_for_digits + = ((((double) number_of_digits_to_use) * LOG_TO_BASE_2_OF_10) + 1); + + more_than_enough_littlenums_for_digits + = (more_than_enough_bits_for_digits + / LITTLENUM_NUMBER_OF_BITS) + + 2; + + /* Compute (digits) part. In "12.34E56" this is the "1234" part. + Arithmetic is exact here. If no digits are supplied then this + part is a 0 valued binary integer. Allocate room to build up + the binary number as littlenums. We want this memory to + disappear when we leave this function. Assume no alignment + problems => (room for n objects) == n * (room for 1 + object). */ + + size_of_digits_in_littlenums = more_than_enough_littlenums_for_digits; + size_of_digits_in_chars = size_of_digits_in_littlenums + * sizeof (LITTLENUM_TYPE); + + digits_binary_low = (LITTLENUM_TYPE *) + alloca (size_of_digits_in_chars); + + memset ((char *) digits_binary_low, '\0', size_of_digits_in_chars); + + /* Digits_binary_low[] is allocated and zeroed. */ + + /* + * Parse the decimal digits as if * digits_low was in the units position. + * Emit a binary number into digits_binary_low[]. + * + * Use a large-precision version of: + * (((1st-digit) * 10 + 2nd-digit) * 10 + 3rd-digit ...) * 10 + last-digit + */ + + for (p = first_digit, count = number_of_digits_to_use; count; p++, --count) + { + c = *p; + if (isdigit (c)) + { + /* + * Multiply by 10. Assume can never overflow. + * Add this digit to digits_binary_low[]. + */ + + long carry; + LITTLENUM_TYPE *littlenum_pointer; + LITTLENUM_TYPE *littlenum_limit; + + littlenum_limit = digits_binary_low + + more_than_enough_littlenums_for_digits + - 1; + + carry = c - '0'; /* char -> binary */ + + for (littlenum_pointer = digits_binary_low; + littlenum_pointer <= littlenum_limit; + littlenum_pointer++) + { + long work; + + work = carry + 10 * (long) (*littlenum_pointer); + *littlenum_pointer = work & LITTLENUM_MASK; + carry = work >> LITTLENUM_NUMBER_OF_BITS; } - - decimal_exponent += number_of_digits_before_decimal - number_of_digits_to_use; - - more_than_enough_bits_for_digits - = ((((double)number_of_digits_to_use) * LOG_TO_BASE_2_OF_10) + 1); - - more_than_enough_littlenums_for_digits - = (more_than_enough_bits_for_digits - / LITTLENUM_NUMBER_OF_BITS) - + 2; - - /* - * Compute (digits) part. In "12.34E56" this is the "1234" part. - * Arithmetic is exact here. If no digits are supplied then - * this part is a 0 valued binary integer. - * Allocate room to build up the binary number as littlenums. - * We want this memory to disappear when we leave this function. - * Assume no alignment problems => (room for n objects) == - * n * (room for 1 object). - */ - - size_of_digits_in_littlenums = more_than_enough_littlenums_for_digits; - size_of_digits_in_chars = size_of_digits_in_littlenums - * sizeof(LITTLENUM_TYPE); - - digits_binary_low = (LITTLENUM_TYPE *) - alloca(size_of_digits_in_chars); - - bzero((char *)digits_binary_low, size_of_digits_in_chars); - - /* Digits_binary_low[] is allocated and zeroed. */ - - /* - * Parse the decimal digits as if * digits_low was in the units position. - * Emit a binary number into digits_binary_low[]. - * - * Use a large-precision version of: - * (((1st-digit) * 10 + 2nd-digit) * 10 + 3rd-digit ...) * 10 + last-digit - */ - - for (p = first_digit, count = number_of_digits_to_use; count; p++, --count) { - c = *p; - if (isdigit(c)) { - /* - * Multiply by 10. Assume can never overflow. - * Add this digit to digits_binary_low[]. - */ - - long carry; - LITTLENUM_TYPE *littlenum_pointer; - LITTLENUM_TYPE *littlenum_limit; - - littlenum_limit = digits_binary_low - + more_than_enough_littlenums_for_digits - - 1; - - carry = c - '0'; /* char -> binary */ - - for (littlenum_pointer = digits_binary_low; - littlenum_pointer <= littlenum_limit; - littlenum_pointer++) { - long work; - - work = carry + 10 * (long) (*littlenum_pointer); - *littlenum_pointer = work & LITTLENUM_MASK; - carry = work >> LITTLENUM_NUMBER_OF_BITS; - } - - if (carry != 0) { - /* - * We have a GROSS internal error. - * This should never happen. - */ - as_fatal("failed sanity check."); /* RMS prefers abort() to any message. */ - } - } else { - ++ count; /* '.' doesn't alter digits used count. */ - } /* if valid digit */ - } /* for each digit */ - - - /* - * Digits_binary_low[] properly encodes the value of the digits. - * Forget about any high-order littlenums that are 0. - */ - while (digits_binary_low[size_of_digits_in_littlenums - 1] == 0 - && size_of_digits_in_littlenums >= 2) - size_of_digits_in_littlenums--; - - digits_flonum.low = digits_binary_low; - digits_flonum.high = digits_binary_low + size_of_digits_in_littlenums - 1; - digits_flonum.leader = digits_flonum.high; - digits_flonum.exponent = 0; - /* - * The value of digits_flonum . sign should not be important. - * We have already decided the output's sign. - * We trust that the sign won't influence the other parts of the number! - * So we give it a value for these reasons: - * (1) courtesy to humans reading/debugging - * these numbers so they don't get excited about strange values - * (2) in future there may be more meaning attached to sign, - * and what was - * harmless noise may become disruptive, ill-conditioned (or worse) - * input. - */ - digits_flonum.sign = '+'; - + + if (carry != 0) { - /* - * Compute the mantssa (& exponent) of the power of 10. - * If sucessful, then multiply the power of 10 by the digits - * giving return_binary_mantissa and return_binary_exponent. - */ - - LITTLENUM_TYPE *power_binary_low; - int decimal_exponent_is_negative; - /* This refers to the "-56" in "12.34E-56". */ - /* FALSE: decimal_exponent is positive (or 0) */ - /* TRUE: decimal_exponent is negative */ - FLONUM_TYPE temporary_flonum; - LITTLENUM_TYPE *temporary_binary_low; - int size_of_power_in_littlenums; - int size_of_power_in_chars; - - size_of_power_in_littlenums = precision; - /* Precision has a built-in fudge factor so we get a few guard bits. */ - - decimal_exponent_is_negative = decimal_exponent < 0; - if (decimal_exponent_is_negative) { - decimal_exponent = -decimal_exponent; - } - - /* From now on: the decimal exponent is > 0. Its sign is seperate. */ - - size_of_power_in_chars = size_of_power_in_littlenums - * sizeof(LITTLENUM_TYPE) + 2; - - power_binary_low = (LITTLENUM_TYPE *) alloca(size_of_power_in_chars); - temporary_binary_low = (LITTLENUM_TYPE *) alloca(size_of_power_in_chars); - bzero((char *)power_binary_low, size_of_power_in_chars); - * power_binary_low = 1; - power_of_10_flonum.exponent = 0; - power_of_10_flonum.low = power_binary_low; - power_of_10_flonum.leader = power_binary_low; - power_of_10_flonum.high = power_binary_low + size_of_power_in_littlenums - 1; - power_of_10_flonum.sign = '+'; - temporary_flonum.low = temporary_binary_low; - temporary_flonum.high = temporary_binary_low + size_of_power_in_littlenums - 1; - /* - * (power) == 1. - * Space for temporary_flonum allocated. - */ - - /* - * ... - * - * WHILE more bits - * DO find next bit (with place value) - * multiply into power mantissa - * OD - */ - { - int place_number_limit; - /* Any 10^(2^n) whose "n" exceeds this */ - /* value will fall off the end of */ - /* flonum_XXXX_powers_of_ten[]. */ - int place_number; - const FLONUM_TYPE *multiplicand; /* -> 10^(2^n) */ - - place_number_limit = table_size_of_flonum_powers_of_ten; - - multiplicand = (decimal_exponent_is_negative - ? flonum_negative_powers_of_ten - : flonum_positive_powers_of_ten); - - for (place_number = 1; /* Place value of this bit of exponent. */ - decimal_exponent; /* Quit when no more 1 bits in exponent. */ - decimal_exponent >>= 1, place_number++) { - if (decimal_exponent & 1) { - if (place_number > place_number_limit) { - /* - * The decimal exponent has a magnitude so great that - * our tables can't help us fragment it. Although this - * routine is in error because it can't imagine a - * number that big, signal an error as if it is the - * user's fault for presenting such a big number. - */ - return_value = ERROR_EXPONENT_OVERFLOW; - /* - * quit out of loop gracefully - */ - decimal_exponent = 0; - } else { + /* + * We have a GROSS internal error. + * This should never happen. + */ + as_fatal ("failed sanity check."); + } + } + else + { + ++count; /* '.' doesn't alter digits used count. */ + } + } + + + /* + * Digits_binary_low[] properly encodes the value of the digits. + * Forget about any high-order littlenums that are 0. + */ + while (digits_binary_low[size_of_digits_in_littlenums - 1] == 0 + && size_of_digits_in_littlenums >= 2) + size_of_digits_in_littlenums--; + + digits_flonum.low = digits_binary_low; + digits_flonum.high = digits_binary_low + size_of_digits_in_littlenums - 1; + digits_flonum.leader = digits_flonum.high; + digits_flonum.exponent = 0; + /* + * The value of digits_flonum . sign should not be important. + * We have already decided the output's sign. + * We trust that the sign won't influence the other parts of the number! + * So we give it a value for these reasons: + * (1) courtesy to humans reading/debugging + * these numbers so they don't get excited about strange values + * (2) in future there may be more meaning attached to sign, + * and what was + * harmless noise may become disruptive, ill-conditioned (or worse) + * input. + */ + digits_flonum.sign = '+'; + + { + /* + * Compute the mantssa (& exponent) of the power of 10. + * If sucessful, then multiply the power of 10 by the digits + * giving return_binary_mantissa and return_binary_exponent. + */ + + LITTLENUM_TYPE *power_binary_low; + int decimal_exponent_is_negative; + /* This refers to the "-56" in "12.34E-56". */ + /* FALSE: decimal_exponent is positive (or 0) */ + /* TRUE: decimal_exponent is negative */ + FLONUM_TYPE temporary_flonum; + LITTLENUM_TYPE *temporary_binary_low; + unsigned int size_of_power_in_littlenums; + unsigned int size_of_power_in_chars; + + size_of_power_in_littlenums = precision; + /* Precision has a built-in fudge factor so we get a few guard bits. */ + + decimal_exponent_is_negative = decimal_exponent < 0; + if (decimal_exponent_is_negative) + { + decimal_exponent = -decimal_exponent; + } + + /* From now on: the decimal exponent is > 0. Its sign is seperate. */ + + size_of_power_in_chars = size_of_power_in_littlenums + * sizeof (LITTLENUM_TYPE) + 2; + + power_binary_low = (LITTLENUM_TYPE *) alloca (size_of_power_in_chars); + temporary_binary_low = (LITTLENUM_TYPE *) alloca (size_of_power_in_chars); + memset ((char *) power_binary_low, '\0', size_of_power_in_chars); + *power_binary_low = 1; + power_of_10_flonum.exponent = 0; + power_of_10_flonum.low = power_binary_low; + power_of_10_flonum.leader = power_binary_low; + power_of_10_flonum.high = power_binary_low + size_of_power_in_littlenums - 1; + power_of_10_flonum.sign = '+'; + temporary_flonum.low = temporary_binary_low; + temporary_flonum.high = temporary_binary_low + size_of_power_in_littlenums - 1; + /* + * (power) == 1. + * Space for temporary_flonum allocated. + */ + + /* + * ... + * + * WHILE more bits + * DO find next bit (with place value) + * multiply into power mantissa + * OD + */ + { + int place_number_limit; + /* Any 10^(2^n) whose "n" exceeds this */ + /* value will fall off the end of */ + /* flonum_XXXX_powers_of_ten[]. */ + int place_number; + const FLONUM_TYPE *multiplicand; /* -> 10^(2^n) */ + + place_number_limit = table_size_of_flonum_powers_of_ten; + + multiplicand = (decimal_exponent_is_negative + ? flonum_negative_powers_of_ten + : flonum_positive_powers_of_ten); + + for (place_number = 1;/* Place value of this bit of exponent. */ + decimal_exponent;/* Quit when no more 1 bits in exponent. */ + decimal_exponent >>= 1, place_number++) + { + if (decimal_exponent & 1) + { + if (place_number > place_number_limit) + { + /* The decimal exponent has a magnitude so great + that our tables can't help us fragment it. + Although this routine is in error because it + can't imagine a number that big, signal an + error as if it is the user's fault for + presenting such a big number. */ + return_value = ERROR_EXPONENT_OVERFLOW; + /* quit out of loop gracefully */ + decimal_exponent = 0; + } + else + { #ifdef TRACE - printf("before multiply, place_number = %d., power_of_10_flonum:\n", - place_number); + printf ("before multiply, place_number = %d., power_of_10_flonum:\n", + place_number); - flonum_print(&power_of_10_flonum); - (void)putchar('\n'); + flonum_print (&power_of_10_flonum); + (void) putchar ('\n'); #endif - flonum_multip(multiplicand + place_number, - &power_of_10_flonum, &temporary_flonum); - flonum_copy(&temporary_flonum, &power_of_10_flonum); - } /* If this bit of decimal_exponent was computable.*/ - } /* If this bit of decimal_exponent was set. */ - } /* For each bit of binary representation of exponent */ + flonum_multip (multiplicand + place_number, + &power_of_10_flonum, &temporary_flonum); + flonum_copy (&temporary_flonum, &power_of_10_flonum); + } /* If this bit of decimal_exponent was computable.*/ + } /* If this bit of decimal_exponent was set. */ + } /* For each bit of binary representation of exponent */ #ifdef TRACE - printf(" after computing power_of_10_flonum: "); - flonum_print(&power_of_10_flonum ); - (void) putchar('\n'); + printf (" after computing power_of_10_flonum: "); + flonum_print (&power_of_10_flonum); + (void) putchar ('\n'); #endif - } - - } - - /* - * power_of_10_flonum is power of ten in binary (mantissa) , (exponent). - * It may be the number 1, in which case we don't NEED to multiply. - * - * Multiply (decimal digits) by power_of_10_flonum. - */ - - flonum_multip(&power_of_10_flonum, &digits_flonum, address_of_generic_floating_point_number); - /* Assert sign of the number we made is '+'. */ - address_of_generic_floating_point_number->sign = digits_sign_char; - - } /* If we had any significant digits. */ - return(return_value); -} /* atof_generic () */ + } + + } + + /* + * power_of_10_flonum is power of ten in binary (mantissa) , (exponent). + * It may be the number 1, in which case we don't NEED to multiply. + * + * Multiply (decimal digits) by power_of_10_flonum. + */ + + flonum_multip (&power_of_10_flonum, &digits_flonum, address_of_generic_floating_point_number); + /* Assert sign of the number we made is '+'. */ + address_of_generic_floating_point_number->sign = digits_sign_char; + + } + return return_value; +} /* end of atof_generic.c */ |