X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=libiberty%2Ffloatformat.c;h=2fd5e688ec4177ca91cdf2cd4d92b3ac34ffe409;hb=refs%2Fheads%2Fconcurrent-displaced-stepping-2020-04-01;hp=b892dbea40ef89cc57a2c67aacc3819d585a48ad;hpb=3f2aacafdc2e8172de64e7aa47f7e9cec631b53c;p=deliverable%2Fbinutils-gdb.git diff --git a/libiberty/floatformat.c b/libiberty/floatformat.c index b892dbea40..2fd5e688ec 100644 --- a/libiberty/floatformat.c +++ b/libiberty/floatformat.c @@ -1,5 +1,5 @@ /* IEEE floating point support routines, for GDB, the GNU Debugger. - Copyright (C) 1991, 1994, 1999, 2000, 2003 Free Software Foundation, Inc. + Copyright (C) 1991-2020 Free Software Foundation, Inc. This file is part of GDB. @@ -15,49 +15,117 @@ 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. */ +Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* This is needed to pick up the NAN macro on some systems. */ +#ifndef _GNU_SOURCE +#define _GNU_SOURCE +#endif + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include + +#ifdef HAVE_STRING_H +#include +#endif + +/* On some platforms, provides DBL_QNAN. */ +#ifdef STDC_HEADERS +#include +#endif #include "ansidecl.h" +#include "libiberty.h" #include "floatformat.h" -#include /* ldexp */ -#ifdef ANSI_PROTOTYPES -#include -extern void *memcpy (void *s1, const void *s2, size_t n); -extern void *memset (void *s, int c, size_t n); + +#ifndef INFINITY +#ifdef HUGE_VAL +#define INFINITY HUGE_VAL #else -extern char *memcpy (); -extern char *memset (); +#define INFINITY (1.0 / 0.0) +#endif #endif +#ifndef NAN +#ifdef DBL_QNAN +#define NAN DBL_QNAN +#else +#define NAN (0.0 / 0.0) +#endif +#endif + +static int mant_bits_set (const struct floatformat *, const unsigned char *); +static unsigned long get_field (const unsigned char *, + enum floatformat_byteorders, + unsigned int, + unsigned int, + unsigned int); +static int floatformat_always_valid (const struct floatformat *fmt, + const void *from); + +static int +floatformat_always_valid (const struct floatformat *fmt ATTRIBUTE_UNUSED, + const void *from ATTRIBUTE_UNUSED) +{ + return 1; +} + /* 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. */ +/* floatformats for IEEE half, single and double, big and little endian. */ +const struct floatformat floatformat_ieee_half_big = +{ + floatformat_big, 16, 0, 1, 5, 15, 31, 6, 10, + floatformat_intbit_no, + "floatformat_ieee_half_big", + floatformat_always_valid, + NULL +}; +const struct floatformat floatformat_ieee_half_little = +{ + floatformat_little, 16, 0, 1, 5, 15, 31, 6, 10, + floatformat_intbit_no, + "floatformat_ieee_half_little", + floatformat_always_valid, + NULL +}; const struct floatformat floatformat_ieee_single_big = { floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23, floatformat_intbit_no, - "floatformat_ieee_single_big" + "floatformat_ieee_single_big", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_ieee_single_little = { floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23, floatformat_intbit_no, - "floatformat_ieee_single_little" + "floatformat_ieee_single_little", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_ieee_double_big = { floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52, floatformat_intbit_no, - "floatformat_ieee_double_big" + "floatformat_ieee_double_big", + floatformat_always_valid, + NULL }; 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_ieee_double_little", + floatformat_always_valid, + NULL }; /* floatformat for IEEE double, little endian byte order, with big endian word @@ -67,34 +135,95 @@ 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_littlebyte_bigword" + "floatformat_ieee_double_littlebyte_bigword", + floatformat_always_valid, + NULL +}; + +/* floatformat for VAX. Not quite IEEE, but close enough. */ + +const struct floatformat floatformat_vax_f = +{ + floatformat_vax, 32, 0, 1, 8, 129, 0, 9, 23, + floatformat_intbit_no, + "floatformat_vax_f", + floatformat_always_valid, + NULL +}; +const struct floatformat floatformat_vax_d = +{ + floatformat_vax, 64, 0, 1, 8, 129, 0, 9, 55, + floatformat_intbit_no, + "floatformat_vax_d", + floatformat_always_valid, + NULL +}; +const struct floatformat floatformat_vax_g = +{ + floatformat_vax, 64, 0, 1, 11, 1025, 0, 12, 52, + floatformat_intbit_no, + "floatformat_vax_g", + floatformat_always_valid, + NULL }; +static int floatformat_i387_ext_is_valid (const struct floatformat *fmt, + const void *from); + +static int +floatformat_i387_ext_is_valid (const struct floatformat *fmt, const void *from) +{ + /* In the i387 double-extended format, if the exponent is all ones, + then the integer bit must be set. If the exponent is neither 0 + nor ~0, the intbit must also be set. Only if the exponent is + zero can it be zero, and then it must be zero. */ + unsigned long exponent, int_bit; + const unsigned char *ufrom = (const unsigned char *) from; + + exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, + fmt->exp_start, fmt->exp_len); + int_bit = get_field (ufrom, fmt->byteorder, fmt->totalsize, + fmt->man_start, 1); + + if ((exponent == 0) != (int_bit == 0)) + return 0; + else + return 1; +} + const struct floatformat floatformat_i387_ext = { floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64, floatformat_intbit_yes, - "floatformat_i387_ext" + "floatformat_i387_ext", + floatformat_i387_ext_is_valid, + NULL }; 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" + "floatformat_m68881_ext", + floatformat_always_valid, + NULL }; 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" + "floatformat_i960_ext", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_m88110_ext = { floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64, floatformat_intbit_yes, - "floatformat_m88110_ext" + "floatformat_m88110_ext", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_m88110_harris_ext = { @@ -102,146 +231,301 @@ const struct floatformat floatformat_m88110_harris_ext = 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" + "floatformat_m88110_ext_harris", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_arm_ext_big = { /* Bits 1 to 16 are unused. */ floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64, floatformat_intbit_yes, - "floatformat_arm_ext_big" + "floatformat_arm_ext_big", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_arm_ext_littlebyte_bigword = { /* Bits 1 to 16 are unused. */ floatformat_littlebyte_bigword, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64, floatformat_intbit_yes, - "floatformat_arm_ext_littlebyte_bigword" + "floatformat_arm_ext_littlebyte_bigword", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_ia64_spill_big = { floatformat_big, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64, floatformat_intbit_yes, - "floatformat_ia64_spill_big" + "floatformat_ia64_spill_big", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_ia64_spill_little = { floatformat_little, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64, floatformat_intbit_yes, - "floatformat_ia64_spill_little" + "floatformat_ia64_spill_little", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_ia64_quad_big = { floatformat_big, 128, 0, 1, 15, 16383, 0x7fff, 16, 112, floatformat_intbit_no, - "floatformat_ia64_quad_big" + "floatformat_ia64_quad_big", + floatformat_always_valid, + NULL }; const struct floatformat floatformat_ia64_quad_little = { floatformat_little, 128, 0, 1, 15, 16383, 0x7fff, 16, 112, floatformat_intbit_no, - "floatformat_ia64_quad_little" + "floatformat_ia64_quad_little", + floatformat_always_valid, + NULL +}; + +static int +floatformat_ibm_long_double_is_valid (const struct floatformat *fmt, + const void *from) +{ + const unsigned char *ufrom = (const unsigned char *) from; + const struct floatformat *hfmt = fmt->split_half; + long top_exp, bot_exp; + int top_nan = 0; + + top_exp = get_field (ufrom, hfmt->byteorder, hfmt->totalsize, + hfmt->exp_start, hfmt->exp_len); + bot_exp = get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize, + hfmt->exp_start, hfmt->exp_len); + + if ((unsigned long) top_exp == hfmt->exp_nan) + top_nan = mant_bits_set (hfmt, ufrom); + + /* A NaN is valid with any low part. */ + if (top_nan) + return 1; + + /* An infinity, zero or denormal requires low part 0 (positive or + negative). */ + if ((unsigned long) top_exp == hfmt->exp_nan || top_exp == 0) + { + if (bot_exp != 0) + return 0; + + return !mant_bits_set (hfmt, ufrom + 8); + } + + /* The top part is now a finite normal value. The long double value + is the sum of the two parts, and the top part must equal the + result of rounding the long double value to nearest double. Thus + the bottom part must be <= 0.5ulp of the top part in absolute + value, and if it is < 0.5ulp then the long double is definitely + valid. */ + if (bot_exp < top_exp - 53) + return 1; + if (bot_exp > top_exp - 53 && bot_exp != 0) + return 0; + if (bot_exp == 0) + { + /* The bottom part is 0 or denormal. Determine which, and if + denormal the first two set bits. */ + int first_bit = -1, second_bit = -1, cur_bit; + for (cur_bit = 0; (unsigned int) cur_bit < hfmt->man_len; cur_bit++) + if (get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize, + hfmt->man_start + cur_bit, 1)) + { + if (first_bit == -1) + first_bit = cur_bit; + else + { + second_bit = cur_bit; + break; + } + } + /* Bottom part 0 is OK. */ + if (first_bit == -1) + return 1; + /* The real exponent of the bottom part is -first_bit. */ + if (-first_bit < top_exp - 53) + return 1; + if (-first_bit > top_exp - 53) + return 0; + /* The bottom part is at least 0.5ulp of the top part. For this + to be OK, the bottom part must be exactly 0.5ulp (i.e. no + more bits set) and the top part must have last bit 0. */ + if (second_bit != -1) + return 0; + return !get_field (ufrom, hfmt->byteorder, hfmt->totalsize, + hfmt->man_start + hfmt->man_len - 1, 1); + } + else + { + /* The bottom part is at least 0.5ulp of the top part. For this + to be OK, it must be exactly 0.5ulp (i.e. no explicit bits + set) and the top part must have last bit 0. */ + if (get_field (ufrom, hfmt->byteorder, hfmt->totalsize, + hfmt->man_start + hfmt->man_len - 1, 1)) + return 0; + return !mant_bits_set (hfmt, ufrom + 8); + } +} + +const struct floatformat floatformat_ibm_long_double_big = +{ + floatformat_big, 128, 0, 1, 11, 1023, 2047, 12, 52, + floatformat_intbit_no, + "floatformat_ibm_long_double_big", + floatformat_ibm_long_double_is_valid, + &floatformat_ieee_double_big +}; + +const struct floatformat floatformat_ibm_long_double_little = +{ + floatformat_little, 128, 0, 1, 11, 1023, 2047, 12, 52, + floatformat_intbit_no, + "floatformat_ibm_long_double_little", + floatformat_ibm_long_double_is_valid, + &floatformat_ieee_double_little }; -static unsigned long get_field PARAMS ((unsigned char *, - enum floatformat_byteorders, - unsigned int, - unsigned int, - unsigned int)); + +#ifndef min +#define min(a, b) ((a) < (b) ? (a) : (b)) +#endif + +/* Return 1 if any bits are explicitly set in the mantissa of UFROM, + format FMT, 0 otherwise. */ +static int +mant_bits_set (const struct floatformat *fmt, const unsigned char *ufrom) +{ + unsigned int mant_bits, mant_off; + int mant_bits_left; + + mant_off = fmt->man_start; + mant_bits_left = fmt->man_len; + while (mant_bits_left > 0) + { + mant_bits = min (mant_bits_left, 32); + + if (get_field (ufrom, fmt->byteorder, fmt->totalsize, + mant_off, mant_bits) != 0) + return 1; + + mant_off += mant_bits; + mant_bits_left -= mant_bits; + } + return 0; +} /* Extract a field which starts at START and is LEN bits 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; +get_field (const unsigned char *data, enum floatformat_byteorders order, + unsigned int total_len, unsigned int start, unsigned int len) +{ + unsigned long result = 0; unsigned int cur_byte; - int cur_bitshift; + int lo_bit, hi_bit, cur_bitshift = 0; + int nextbyte = (order == floatformat_little) ? 1 : -1; + + /* Start is in big-endian bit order! Fix that first. */ + start = total_len - (start + len); /* 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; + cur_byte = start / FLOATFORMAT_CHAR_BIT; else - --cur_byte; + cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; - /* Move towards the most significant part of the field. */ - while ((unsigned int) cur_bitshift < len) + lo_bit = start % FLOATFORMAT_CHAR_BIT; + hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); + + do { - 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; + unsigned int shifted = *(data + cur_byte) >> lo_bit; + unsigned int bits = hi_bit - lo_bit; + unsigned int mask = (1 << bits) - 1; + result |= (shifted & mask) << cur_bitshift; + len -= bits; + cur_bitshift += bits; + cur_byte += nextbyte; + lo_bit = 0; + hi_bit = min (len, FLOATFORMAT_CHAR_BIT); } + while (len != 0); + 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; +floatformat_to_double (const struct floatformat *fmt, + const void *from, double *to) { - unsigned char *ufrom = (unsigned char *)from; + const unsigned char *ufrom = (const 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 */ + + /* Split values are not handled specially, since the top half has + the correctly rounded double value (in the only supported case of + split values). */ 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. */ + + /* If the exponent indicates a NaN, we don't have information to + decide what to do. So we handle it like IEEE, except that we + don't try to preserve the type of NaN. FIXME. */ + if ((unsigned long) exponent == fmt->exp_nan) + { + int nan = mant_bits_set (fmt, ufrom); + + /* On certain systems (such as GNU/Linux), the use of the + INFINITY macro below may generate a warning that cannot be + silenced due to a bug in GCC (PR preprocessor/11931). The + preprocessor fails to recognise the __extension__ keyword in + conjunction with the GNU/C99 extension for hexadecimal + floating point constants and will issue a warning when + compiling with -pedantic. */ + if (nan) + dto = NAN; + else + dto = INFINITY; + + if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) + dto = -dto; + + *to = dto; + + return; + } 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) + /* For denorms use minimum exponent. */ + if (exponent == 0) + exponent = 1 - fmt->exp_bias; + else { + exponent -= fmt->exp_bias; + + /* 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 (fmt->intbit == floatformat_intbit_no) dto = ldexp (1.0, exponent); else @@ -255,7 +539,7 @@ floatformat_to_double (fmt, from, to) mant = get_field (ufrom, fmt->byteorder, fmt->totalsize, mant_off, mant_bits); - dto += ldexp ((double)mant, exponent - mant_bits); + dto += ldexp ((double) mant, exponent - mant_bits); exponent -= mant_bits; mant_off += mant_bits; mant_bits_left -= mant_bits; @@ -267,61 +551,48 @@ floatformat_to_double (fmt, from, to) *to = dto; } -static void put_field PARAMS ((unsigned char *, enum floatformat_byteorders, - unsigned int, - unsigned int, - unsigned int, - unsigned long)); +static void put_field (unsigned char *, enum floatformat_byteorders, + unsigned int, + unsigned int, + unsigned int, + unsigned long); /* Set a field which starts at START and is LEN bits 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; +put_field (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; + int lo_bit, hi_bit; + int nextbyte = (order == floatformat_little) ? 1 : -1; + + /* Start is in big-endian bit order! Fix that first. */ + start = total_len - (start + len); /* 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; + cur_byte = start / FLOATFORMAT_CHAR_BIT; else - --cur_byte; + cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; - /* Move towards the most significant part of the field. */ - while ((unsigned int) cur_bitshift < len) + lo_bit = start % FLOATFORMAT_CHAR_BIT; + hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); + + do { - 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; + unsigned char *byte_ptr = data + cur_byte; + unsigned int bits = hi_bit - lo_bit; + unsigned int mask = ((1 << bits) - 1) << lo_bit; + *byte_ptr = (*byte_ptr & ~mask) | ((stuff_to_put << lo_bit) & mask); + stuff_to_put >>= bits; + len -= bits; + cur_byte += nextbyte; + lo_bit = 0; + hi_bit = min (len, FLOATFORMAT_CHAR_BIT); } + while (len != 0); } /* The converse: convert the double *FROM to an extended float @@ -329,45 +600,68 @@ put_field (data, order, total_len, start, len, stuff_to_put) restrictions. */ void -floatformat_from_double (fmt, from, to) - const struct floatformat *fmt; - double *from; - char *to; +floatformat_from_double (const struct floatformat *fmt, + const double *from, void *to) { double dfrom; int exponent; double mant; unsigned int mant_bits, mant_off; int mant_bits_left; - unsigned char *uto = (unsigned char *)to; + unsigned char *uto = (unsigned char *) to; - memcpy (&dfrom, from, sizeof (dfrom)); + dfrom = *from; memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT); + + /* Split values are not handled specially, since a bottom half of + zero is correct for any value representable as double (in the + only supported case of split values). */ + + /* If negative, set the sign bit. */ + if (dfrom < 0) + { + put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1); + dfrom = -dfrom; + } + if (dfrom == 0) - return; /* Result is zero */ + { + /* 0.0. */ + return; + } + if (dfrom != dfrom) { - /* From is NaN */ + /* 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 */ + /* Be sure it's not infinity, but NaN value is irrelevant. */ put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, 32, 1); return; } - /* If negative, set the sign bit. */ - if (dfrom < 0) + if (dfrom + dfrom == dfrom) { - put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1); - dfrom = -dfrom; + /* This can only happen for an infinite value (or zero, which we + already handled above). */ + put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, + fmt->exp_len, fmt->exp_nan); + return; } - /* 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); + if (exponent + fmt->exp_bias - 1 > 0) + put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, + fmt->exp_len, exponent + fmt->exp_bias - 1); + else + { + /* Handle a denormalized number. FIXME: What should we do for + non-IEEE formats? */ + put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, + fmt->exp_len, 0); + mant = ldexp (mant, exponent + fmt->exp_bias - 1); + } mant_bits_left = fmt->man_len; mant_off = fmt->man_start; @@ -380,12 +674,11 @@ floatformat_from_double (fmt, from, to) 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 the integer bit is implicit, and we are not creating a + denormalized number, then we need to discard it. */ if ((unsigned int) mant_bits_left == fmt->man_len - && fmt->intbit == floatformat_intbit_no) + && fmt->intbit == floatformat_intbit_no + && exponent + fmt->exp_bias - 1 > 0) { mant_long &= 0x7fffffff; mant_bits -= 1; @@ -407,59 +700,45 @@ floatformat_from_double (fmt, from, to) /* Return non-zero iff the data at FROM is a valid number in format FMT. */ int -floatformat_is_valid (fmt, from) - const struct floatformat *fmt; - char *from; +floatformat_is_valid (const struct floatformat *fmt, const void *from) { - if (fmt == &floatformat_i387_ext) - { - /* In the i387 double-extended format, if the exponent is all - ones, then the integer bit must be set. If the exponent - is neither 0 nor ~0, the intbit must also be set. Only - if the exponent is zero can it be zero, and then it must - be zero. */ - unsigned long exponent, int_bit; - unsigned char *ufrom = (unsigned char *) from; - - exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, - fmt->exp_start, fmt->exp_len); - int_bit = get_field (ufrom, fmt->byteorder, fmt->totalsize, - fmt->man_start, 1); - - if ((exponent == 0) != (int_bit == 0)) - return 0; - else - return 1; - } - - /* Other formats with invalid representations should be added - here. */ - return 1; + return fmt->is_valid (fmt, from); } #ifdef IEEE_DEBUG +#include + /* This is to be run on a host which uses IEEE floating point. */ void -ieee_test (n) - double n; +ieee_test (double n) { double result; - char exten[16]; - floatformat_to_double (&floatformat_ieee_double_big, &n, &result); - if (n != result) + floatformat_to_double (&floatformat_ieee_double_little, &n, &result); + if ((n != result && (! isnan (n) || ! isnan (result))) + || (n < 0 && result >= 0) + || (n >= 0 && result < 0)) printf ("Differ(to): %.20g -> %.20g\n", n, result); - floatformat_from_double (&floatformat_ieee_double_big, &n, &result); - if (n != result) + + floatformat_from_double (&floatformat_ieee_double_little, &n, &result); + if ((n != result && (! isnan (n) || ! isnan (result))) + || (n < 0 && result >= 0) + || (n >= 0 && result < 0)) 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 0 + { + char exten[16]; + + 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); + } +#endif #if IEEE_DEBUG > 1 /* This is to be run on a host which uses 68881 format. */ @@ -472,14 +751,25 @@ ieee_test (n) } int -main () +main (void) { + ieee_test (0.0); ieee_test (0.5); + ieee_test (1.1); ieee_test (256.0); ieee_test (0.12345); ieee_test (234235.78907234); ieee_test (-512.0); ieee_test (-0.004321); + ieee_test (1.2E-70); + ieee_test (1.2E-316); + ieee_test (4.9406564584124654E-324); + ieee_test (- 4.9406564584124654E-324); + ieee_test (- 0.0); + ieee_test (- INFINITY); + ieee_test (- NAN); + ieee_test (INFINITY); + ieee_test (NAN); return 0; } #endif