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Diffstat (limited to 'libiberty/floatformat.c')
| -rw-r--r-- | libiberty/floatformat.c | 420 |
1 files changed, 0 insertions, 420 deletions
diff --git a/libiberty/floatformat.c b/libiberty/floatformat.c deleted file mode 100644 index 3cb78f51dde..00000000000 --- a/libiberty/floatformat.c +++ /dev/null @@ -1,420 +0,0 @@ -/* IEEE floating point support routines, for GDB, the GNU Debugger. - Copyright (C) 1991, 1994, 1999, 2000 Free Software Foundation, Inc. - -This file is part of GDB. - -This program 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 of the License, or -(at your option) any later version. - -This program 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 this program; if not, write to the Free Software -Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ - -#include "floatformat.h" -#include <math.h> /* ldexp */ -#ifdef __STDC__ -#include <stddef.h> -extern void *memcpy (void *s1, const void *s2, size_t n); -extern void *memset (void *s, int c, size_t n); -#else -extern char *memcpy (); -extern char *memset (); -#endif - -/* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not - going to bother with trying to muck around with whether it is defined in - a system header, what we do if not, etc. */ -#define FLOATFORMAT_CHAR_BIT 8 - -/* floatformats for IEEE single and double, big and little endian. */ -const struct floatformat floatformat_ieee_single_big = -{ - floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23, - floatformat_intbit_no, - "floatformat_ieee_single_big" -}; -const struct floatformat floatformat_ieee_single_little = -{ - floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23, - floatformat_intbit_no, - "floatformat_ieee_single_little" -}; -const struct floatformat floatformat_ieee_double_big = -{ - floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52, - floatformat_intbit_no, - "floatformat_ieee_double_big" -}; -const struct floatformat floatformat_ieee_double_little = -{ - floatformat_little, 64, 0, 1, 11, 1023, 2047, 12, 52, - floatformat_intbit_no, - "floatformat_ieee_double_little" -}; - -/* floatformat for IEEE double, little endian byte order, with big endian word - ordering, as on the ARM. */ - -const struct floatformat floatformat_ieee_double_littlebyte_bigword = -{ - floatformat_littlebyte_bigword, 64, 0, 1, 11, 1023, 2047, 12, 52, - floatformat_intbit_no, - "floatformat_ieee_double_little" -}; - -const struct floatformat floatformat_i387_ext = -{ - floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64, - floatformat_intbit_yes, - "floatformat_i387_ext" -}; -const struct floatformat floatformat_m68881_ext = -{ - /* Note that the bits from 16 to 31 are unused. */ - floatformat_big, 96, 0, 1, 15, 0x3fff, 0x7fff, 32, 64, - floatformat_intbit_yes, - "floatformat_m68881_ext" -}; -const struct floatformat floatformat_i960_ext = -{ - /* Note that the bits from 0 to 15 are unused. */ - floatformat_little, 96, 16, 17, 15, 0x3fff, 0x7fff, 32, 64, - floatformat_intbit_yes, - "floatformat_i960_ext" -}; -const struct floatformat floatformat_m88110_ext = -{ -#ifdef HARRIS_FLOAT_FORMAT - /* Harris uses raw format 128 bytes long, but the number is just an ieee - double, and the last 64 bits are wasted. */ - floatformat_big,128, 0, 1, 11, 0x3ff, 0x7ff, 12, 52, - floatformat_intbit_no, - "floatformat_m88110_ext(harris)" -#else - floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64, - floatformat_intbit_yes, - "floatformat_m88110_ext" -#endif /* HARRIS_FLOAT_FORMAT */ -}; -const struct floatformat floatformat_arm_ext = -{ - /* Bits 1 to 16 are unused. */ - floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64, - floatformat_intbit_yes, - "floatformat_arm_ext" -}; - -static unsigned long get_field PARAMS ((unsigned char *, - enum floatformat_byteorders, - unsigned int, - unsigned int, - unsigned int)); - -/* Extract a field which starts at START and is LEN bytes long. DATA and - TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ -static unsigned long -get_field (data, order, total_len, start, len) - unsigned char *data; - enum floatformat_byteorders order; - unsigned int total_len; - unsigned int start; - unsigned int len; -{ - unsigned long result; - unsigned int cur_byte; - int cur_bitshift; - - /* Start at the least significant part of the field. */ - cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1; - cur_bitshift = - ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; - result = *(data + cur_byte) >> (-cur_bitshift); - cur_bitshift += FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - ++cur_byte; - else - --cur_byte; - - /* Move towards the most significant part of the field. */ - while ((unsigned int) cur_bitshift < len) - { - if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) - /* This is the last byte; zero out the bits which are not part of - this field. */ - result |= - (*(data + cur_byte) & ((1 << (len - cur_bitshift)) - 1)) - << cur_bitshift; - else - result |= *(data + cur_byte) << cur_bitshift; - cur_bitshift += FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - ++cur_byte; - else - --cur_byte; - } - return result; -} - -#ifndef min -#define min(a, b) ((a) < (b) ? (a) : (b)) -#endif - -/* Convert from FMT to a double. - FROM is the address of the extended float. - Store the double in *TO. */ - -void -floatformat_to_double (fmt, from, to) - const struct floatformat *fmt; - char *from; - double *to; -{ - unsigned char *ufrom = (unsigned char *)from; - double dto; - long exponent; - unsigned long mant; - unsigned int mant_bits, mant_off; - int mant_bits_left; - int special_exponent; /* It's a NaN, denorm or zero */ - - exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, - fmt->exp_start, fmt->exp_len); - /* Note that if exponent indicates a NaN, we can't really do anything useful - (not knowing if the host has NaN's, or how to build one). So it will - end up as an infinity or something close; that is OK. */ - - mant_bits_left = fmt->man_len; - mant_off = fmt->man_start; - dto = 0.0; - - special_exponent = exponent == 0 || (unsigned long) exponent == fmt->exp_nan; - - /* Don't bias zero's, denorms or NaNs. */ - if (!special_exponent) - exponent -= fmt->exp_bias; - - /* Build the result algebraically. Might go infinite, underflow, etc; - who cares. */ - - /* If this format uses a hidden bit, explicitly add it in now. Otherwise, - increment the exponent by one to account for the integer bit. */ - - if (!special_exponent) - { - if (fmt->intbit == floatformat_intbit_no) - dto = ldexp (1.0, exponent); - else - exponent++; - } - - while (mant_bits_left > 0) - { - mant_bits = min (mant_bits_left, 32); - - mant = get_field (ufrom, fmt->byteorder, fmt->totalsize, - mant_off, mant_bits); - - dto += ldexp ((double)mant, exponent - mant_bits); - exponent -= mant_bits; - mant_off += mant_bits; - mant_bits_left -= mant_bits; - } - - /* Negate it if negative. */ - if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) - dto = -dto; - *to = dto; -} - -static void put_field PARAMS ((unsigned char *, enum floatformat_byteorders, - unsigned int, - unsigned int, - unsigned int, - unsigned long)); - -/* Set a field which starts at START and is LEN bytes long. DATA and - TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ -static void -put_field (data, order, total_len, start, len, stuff_to_put) - unsigned char *data; - enum floatformat_byteorders order; - unsigned int total_len; - unsigned int start; - unsigned int len; - unsigned long stuff_to_put; -{ - unsigned int cur_byte; - int cur_bitshift; - - /* Start at the least significant part of the field. */ - cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) - cur_byte - 1; - cur_bitshift = - ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; - *(data + cur_byte) &= - ~(((1 << ((start + len) % FLOATFORMAT_CHAR_BIT)) - 1) << (-cur_bitshift)); - *(data + cur_byte) |= - (stuff_to_put & ((1 << FLOATFORMAT_CHAR_BIT) - 1)) << (-cur_bitshift); - cur_bitshift += FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - ++cur_byte; - else - --cur_byte; - - /* Move towards the most significant part of the field. */ - while ((unsigned int) cur_bitshift < len) - { - if (len - cur_bitshift < FLOATFORMAT_CHAR_BIT) - { - /* This is the last byte. */ - *(data + cur_byte) &= - ~((1 << (len - cur_bitshift)) - 1); - *(data + cur_byte) |= (stuff_to_put >> cur_bitshift); - } - else - *(data + cur_byte) = ((stuff_to_put >> cur_bitshift) - & ((1 << FLOATFORMAT_CHAR_BIT) - 1)); - cur_bitshift += FLOATFORMAT_CHAR_BIT; - if (order == floatformat_little) - ++cur_byte; - else - --cur_byte; - } -} - -/* The converse: convert the double *FROM to an extended float - and store where TO points. Neither FROM nor TO have any alignment - restrictions. */ - -void -floatformat_from_double (fmt, from, to) - const struct floatformat *fmt; - double *from; - char *to; -{ - double dfrom; - int exponent; - double mant; - unsigned int mant_bits, mant_off; - int mant_bits_left; - unsigned char *uto = (unsigned char *)to; - - memcpy (&dfrom, from, sizeof (dfrom)); - memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT); - if (dfrom == 0) - return; /* Result is zero */ - if (dfrom != dfrom) - { - /* From is NaN */ - put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, - fmt->exp_len, fmt->exp_nan); - /* Be sure it's not infinity, but NaN value is irrel */ - put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, - 32, 1); - return; - } - - /* If negative, set the sign bit. */ - if (dfrom < 0) - { - put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1); - dfrom = -dfrom; - } - - /* How to tell an infinity from an ordinary number? FIXME-someday */ - - mant = frexp (dfrom, &exponent); - put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, fmt->exp_len, - exponent + fmt->exp_bias - 1); - - mant_bits_left = fmt->man_len; - mant_off = fmt->man_start; - while (mant_bits_left > 0) - { - unsigned long mant_long; - mant_bits = mant_bits_left < 32 ? mant_bits_left : 32; - - mant *= 4294967296.0; - mant_long = (unsigned long)mant; - mant -= mant_long; - - /* If the integer bit is implicit, then we need to discard it. - If we are discarding a zero, we should be (but are not) creating - a denormalized number which means adjusting the exponent - (I think). */ - if ((unsigned int) mant_bits_left == fmt->man_len - && fmt->intbit == floatformat_intbit_no) - { - mant_long &= 0x7fffffff; - mant_bits -= 1; - } - else if (mant_bits < 32) - { - /* The bits we want are in the most significant MANT_BITS bits of - mant_long. Move them to the least significant. */ - mant_long >>= 32 - mant_bits; - } - - put_field (uto, fmt->byteorder, fmt->totalsize, - mant_off, mant_bits, mant_long); - mant_off += mant_bits; - mant_bits_left -= mant_bits; - } -} - - -#ifdef IEEE_DEBUG - -/* This is to be run on a host which uses IEEE floating point. */ - -void -ieee_test (n) - double n; -{ - double result; - char exten[16]; - - floatformat_to_double (&floatformat_ieee_double_big, &n, &result); - if (n != result) - printf ("Differ(to): %.20g -> %.20g\n", n, result); - floatformat_from_double (&floatformat_ieee_double_big, &n, &result); - if (n != result) - printf ("Differ(from): %.20g -> %.20g\n", n, result); - - floatformat_from_double (&floatformat_m68881_ext, &n, exten); - floatformat_to_double (&floatformat_m68881_ext, exten, &result); - if (n != result) - printf ("Differ(to+from): %.20g -> %.20g\n", n, result); - -#if IEEE_DEBUG > 1 - /* This is to be run on a host which uses 68881 format. */ - { - long double ex = *(long double *)exten; - if (ex != n) - printf ("Differ(from vs. extended): %.20g\n", n); - } -#endif -} - -int -main () -{ - ieee_test (0.5); - ieee_test (256.0); - ieee_test (0.12345); - ieee_test (234235.78907234); - ieee_test (-512.0); - ieee_test (-0.004321); - return 0; -} -#endif |