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Diffstat (limited to 'contrib/gdb/gdb/doublest.c')
-rw-r--r-- | contrib/gdb/gdb/doublest.c | 788 |
1 files changed, 788 insertions, 0 deletions
diff --git a/contrib/gdb/gdb/doublest.c b/contrib/gdb/gdb/doublest.c new file mode 100644 index 0000000..a4b4b76 --- /dev/null +++ b/contrib/gdb/gdb/doublest.c @@ -0,0 +1,788 @@ +/* Floating point routines for GDB, the GNU debugger. + Copyright 1986, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, + 1997, 1998, 1999, 2000, 2001 + 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. */ + +/* Support for converting target fp numbers into host DOUBLEST format. */ + +/* XXX - This code should really be in libiberty/floatformat.c, + however configuration issues with libiberty made this very + difficult to do in the available time. */ + +#include "defs.h" +#include "doublest.h" +#include "floatformat.h" +#include "gdb_assert.h" +#include "gdb_string.h" +#include "gdbtypes.h" +#include <math.h> /* ldexp */ + +/* 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 + +static unsigned long get_field (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 (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. */ + if (order == floatformat_little || order == floatformat_littlebyte_bigword) + { + /* We start counting from the other end (i.e, from the high bytes + rather than the low bytes). As such, we need to be concerned + with what happens if bit 0 doesn't start on a byte boundary. + I.e, we need to properly handle the case where total_len is + not evenly divisible by 8. So we compute ``excess'' which + represents the number of bits from the end of our starting + byte needed to get to bit 0. */ + int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); + cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) + - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); + cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) + - FLOATFORMAT_CHAR_BIT; + } + else + { + cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; + cur_bitshift = + ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; + } + if (cur_bitshift > -FLOATFORMAT_CHAR_BIT) + result = *(data + cur_byte) >> (-cur_bitshift); + else + result = 0; + cur_bitshift += FLOATFORMAT_CHAR_BIT; + if (order == floatformat_little || order == floatformat_littlebyte_bigword) + ++cur_byte; + else + --cur_byte; + + /* Move towards the most significant part of the field. */ + while (cur_bitshift < len) + { + result |= (unsigned long)*(data + cur_byte) << cur_bitshift; + cur_bitshift += FLOATFORMAT_CHAR_BIT; + if (order == floatformat_little || order == floatformat_littlebyte_bigword) + ++cur_byte; + else + --cur_byte; + } + if (len < sizeof(result) * FLOATFORMAT_CHAR_BIT) + /* Mask out bits which are not part of the field */ + result &= ((1UL << len) - 1); + return result; +} + +/* Convert from FMT to a DOUBLEST. + FROM is the address of the extended float. + Store the DOUBLEST in *TO. */ + +static void +convert_floatformat_to_doublest (const struct floatformat *fmt, + const void *from, + DOUBLEST *to) +{ + unsigned char *ufrom = (unsigned char *) from; + DOUBLEST 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 */ + + /* If the mantissa bits are not contiguous from one end of the + mantissa to the other, we need to make a private copy of the + source bytes that is in the right order since the unpacking + algorithm assumes that the bits are contiguous. + + Swap the bytes individually rather than accessing them through + "long *" since we have no guarantee that they start on a long + alignment, and also sizeof(long) for the host could be different + than sizeof(long) for the target. FIXME: Assumes sizeof(long) + for the target is 4. */ + + if (fmt->byteorder == floatformat_littlebyte_bigword) + { + static unsigned char *newfrom; + unsigned char *swapin, *swapout; + int longswaps; + + longswaps = fmt->totalsize / FLOATFORMAT_CHAR_BIT; + longswaps >>= 3; + + if (newfrom == NULL) + { + newfrom = (unsigned char *) xmalloc (fmt->totalsize); + } + swapout = newfrom; + swapin = ufrom; + ufrom = newfrom; + while (longswaps-- > 0) + { + /* This is ugly, but efficient */ + *swapout++ = swapin[4]; + *swapout++ = swapin[5]; + *swapout++ = swapin[6]; + *swapout++ = swapin[7]; + *swapout++ = swapin[0]; + *swapout++ = swapin[1]; + *swapout++ = swapin[2]; + *swapout++ = swapin[3]; + swapin += 8; + } + } + + 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 || exponent == fmt->exp_nan; + +/* Don't bias NaNs. Use minimum exponent for denorms. For simplicity, + we don't check for zero as the exponent doesn't matter. */ + if (!special_exponent) + exponent -= fmt->exp_bias; + else if (exponent == 0) + exponent = 1 - 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 (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 (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. */ + if (order == floatformat_little || order == floatformat_littlebyte_bigword) + { + int excess = FLOATFORMAT_CHAR_BIT - (total_len % FLOATFORMAT_CHAR_BIT); + cur_byte = (total_len / FLOATFORMAT_CHAR_BIT) + - ((start + len + excess) / FLOATFORMAT_CHAR_BIT); + cur_bitshift = ((start + len + excess) % FLOATFORMAT_CHAR_BIT) + - FLOATFORMAT_CHAR_BIT; + } + else + { + cur_byte = (start + len) / FLOATFORMAT_CHAR_BIT; + cur_bitshift = + ((start + len) % FLOATFORMAT_CHAR_BIT) - FLOATFORMAT_CHAR_BIT; + } + if (cur_bitshift > -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 || order == floatformat_littlebyte_bigword) + ++cur_byte; + else + --cur_byte; + + /* Move towards the most significant part of the field. */ + while (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 || order == floatformat_littlebyte_bigword) + ++cur_byte; + else + --cur_byte; + } +} + +#ifdef HAVE_LONG_DOUBLE +/* Return the fractional part of VALUE, and put the exponent of VALUE in *EPTR. + The range of the returned value is >= 0.5 and < 1.0. This is equivalent to + frexp, but operates on the long double data type. */ + +static long double ldfrexp (long double value, int *eptr); + +static long double +ldfrexp (long double value, int *eptr) +{ + long double tmp; + int exp; + + /* Unfortunately, there are no portable functions for extracting the exponent + of a long double, so we have to do it iteratively by multiplying or dividing + by two until the fraction is between 0.5 and 1.0. */ + + if (value < 0.0l) + value = -value; + + tmp = 1.0l; + exp = 0; + + if (value >= tmp) /* Value >= 1.0 */ + while (value >= tmp) + { + tmp *= 2.0l; + exp++; + } + else if (value != 0.0l) /* Value < 1.0 and > 0.0 */ + { + while (value < tmp) + { + tmp /= 2.0l; + exp--; + } + tmp *= 2.0l; + exp++; + } + + *eptr = exp; + return value / tmp; +} +#endif /* HAVE_LONG_DOUBLE */ + + +/* The converse: convert the DOUBLEST *FROM to an extended float + and store where TO points. Neither FROM nor TO have any alignment + restrictions. */ + +static void +convert_doublest_to_floatformat (CONST struct floatformat *fmt, + const DOUBLEST *from, + void *to) +{ + DOUBLEST dfrom; + int exponent; + DOUBLEST 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 - 1) + / FLOATFORMAT_CHAR_BIT); + if (dfrom == 0) + return; /* Result is zero */ + if (dfrom != dfrom) /* Result is NaN */ + { + /* 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; + } + + if (dfrom + dfrom == dfrom && dfrom != 0.0) /* Result is Infinity */ + { + /* Infinity exponent is same as NaN's. */ + put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, + fmt->exp_len, fmt->exp_nan); + /* Infinity mantissa is all zeroes. */ + put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, + fmt->man_len, 0); + return; + } + +#ifdef HAVE_LONG_DOUBLE + mant = ldfrexp (dfrom, &exponent); +#else + mant = frexp (dfrom, &exponent); +#endif + + 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) & 0xffffffffL; + 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 (mant_bits_left == fmt->man_len + && fmt->intbit == floatformat_intbit_no) + { + mant_long <<= 1; + mant_long &= 0xffffffffL; + mant_bits -= 1; + } + + 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; + } + if (fmt->byteorder == floatformat_littlebyte_bigword) + { + int count; + unsigned char *swaplow = uto; + unsigned char *swaphigh = uto + 4; + unsigned char tmp; + + for (count = 0; count < 4; count++) + { + tmp = *swaplow; + *swaplow++ = *swaphigh; + *swaphigh++ = tmp; + } + } +} + +/* Check if VAL (which is assumed to be a floating point number whose + format is described by FMT) is negative. */ + +int +floatformat_is_negative (const struct floatformat *fmt, char *val) +{ + unsigned char *uval = (unsigned char *) val; + gdb_assert (fmt != NULL); + return get_field (uval, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1); +} + +/* Check if VAL is "not a number" (NaN) for FMT. */ + +int +floatformat_is_nan (const struct floatformat *fmt, char *val) +{ + unsigned char *uval = (unsigned char *) val; + long exponent; + unsigned long mant; + unsigned int mant_bits, mant_off; + int mant_bits_left; + + gdb_assert (fmt != NULL); + + if (! fmt->exp_nan) + return 0; + + exponent = get_field (uval, fmt->byteorder, fmt->totalsize, + fmt->exp_start, fmt->exp_len); + + if (exponent != fmt->exp_nan) + return 0; + + mant_bits_left = fmt->man_len; + mant_off = fmt->man_start; + + while (mant_bits_left > 0) + { + mant_bits = min (mant_bits_left, 32); + + mant = get_field (uval, fmt->byteorder, fmt->totalsize, + mant_off, mant_bits); + + /* If there is an explicit integer bit, mask it off. */ + if (mant_off == fmt->man_start + && fmt->intbit == floatformat_intbit_yes) + mant &= ~(1 << (mant_bits - 1)); + + if (mant) + return 1; + + mant_off += mant_bits; + mant_bits_left -= mant_bits; + } + + return 0; +} + +/* Convert the mantissa of VAL (which is assumed to be a floating + point number whose format is described by FMT) into a hexadecimal + and store it in a static string. Return a pointer to that string. */ + +char * +floatformat_mantissa (const struct floatformat *fmt, char *val) +{ + unsigned char *uval = (unsigned char *) val; + unsigned long mant; + unsigned int mant_bits, mant_off; + int mant_bits_left; + static char res[50]; + char buf[9]; + + /* Make sure we have enough room to store the mantissa. */ + gdb_assert (fmt != NULL); + gdb_assert (sizeof res > ((fmt->man_len + 7) / 8) * 2); + + mant_off = fmt->man_start; + mant_bits_left = fmt->man_len; + mant_bits = (mant_bits_left % 32) > 0 ? mant_bits_left % 32 : 32; + + mant = get_field (uval, fmt->byteorder, fmt->totalsize, + mant_off, mant_bits); + + sprintf (res, "%lx", mant); + + mant_off += mant_bits; + mant_bits_left -= mant_bits; + + while (mant_bits_left > 0) + { + mant = get_field (uval, fmt->byteorder, fmt->totalsize, + mant_off, 32); + + sprintf (buf, "%08lx", mant); + strcat (res, buf); + + mant_off += 32; + mant_bits_left -= 32; + } + + return res; +} + + +/* Convert TO/FROM target to the hosts DOUBLEST floating-point format. + + If the host and target formats agree, we just copy the raw data + into the appropriate type of variable and return, letting the host + increase precision as necessary. Otherwise, we call the conversion + routine and let it do the dirty work. */ + +#ifndef HOST_FLOAT_FORMAT +#define HOST_FLOAT_FORMAT 0 +#endif +#ifndef HOST_DOUBLE_FORMAT +#define HOST_DOUBLE_FORMAT 0 +#endif +#ifndef HOST_LONG_DOUBLE_FORMAT +#define HOST_LONG_DOUBLE_FORMAT 0 +#endif + +static const struct floatformat *host_float_format = HOST_FLOAT_FORMAT; +static const struct floatformat *host_double_format = HOST_DOUBLE_FORMAT; +static const struct floatformat *host_long_double_format = HOST_LONG_DOUBLE_FORMAT; + +void +floatformat_to_doublest (const struct floatformat *fmt, + const void *in, DOUBLEST *out) +{ + gdb_assert (fmt != NULL); + if (fmt == host_float_format) + { + float val; + memcpy (&val, in, sizeof (val)); + *out = val; + } + else if (fmt == host_double_format) + { + double val; + memcpy (&val, in, sizeof (val)); + *out = val; + } + else if (fmt == host_long_double_format) + { + long double val; + memcpy (&val, in, sizeof (val)); + *out = val; + } + else + convert_floatformat_to_doublest (fmt, in, out); +} + +void +floatformat_from_doublest (const struct floatformat *fmt, + const DOUBLEST *in, void *out) +{ + gdb_assert (fmt != NULL); + if (fmt == host_float_format) + { + float val = *in; + memcpy (out, &val, sizeof (val)); + } + else if (fmt == host_double_format) + { + double val = *in; + memcpy (out, &val, sizeof (val)); + } + else if (fmt == host_long_double_format) + { + long double val = *in; + memcpy (out, &val, sizeof (val)); + } + else + convert_doublest_to_floatformat (fmt, in, out); +} + + +/* Return a floating-point format for a floating-point variable of + length LEN. Return NULL, if no suitable floating-point format + could be found. + + We need this functionality since information about the + floating-point format of a type is not always available to GDB; the + debug information typically only tells us the size of a + floating-point type. + + FIXME: kettenis/2001-10-28: In many places, particularly in + target-dependent code, the format of floating-point types is known, + but not passed on by GDB. This should be fixed. */ + +const struct floatformat * +floatformat_from_length (int len) +{ + if (len * TARGET_CHAR_BIT == TARGET_FLOAT_BIT) + return TARGET_FLOAT_FORMAT; + else if (len * TARGET_CHAR_BIT == TARGET_DOUBLE_BIT) + return TARGET_DOUBLE_FORMAT; + else if (len * TARGET_CHAR_BIT == TARGET_LONG_DOUBLE_BIT) + return TARGET_LONG_DOUBLE_FORMAT; + + return NULL; +} + +const struct floatformat * +floatformat_from_type (const struct type *type) +{ + gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); + if (TYPE_FLOATFORMAT (type) != NULL) + return TYPE_FLOATFORMAT (type); + else + return floatformat_from_length (TYPE_LENGTH (type)); +} + +/* If the host doesn't define NAN, use zero instead. */ +#ifndef NAN +#define NAN 0.0 +#endif + +/* Extract a floating-point number of length LEN from a target-order + byte-stream at ADDR. Returns the value as type DOUBLEST. */ + +DOUBLEST +extract_floating (const void *addr, int len) +{ + const struct floatformat *fmt = floatformat_from_length (len); + DOUBLEST val; + + if (fmt == NULL) + { + warning ("Can't store a floating-point number of %d bytes.", len); + return NAN; + } + + floatformat_to_doublest (fmt, addr, &val); + return val; +} + +/* Store VAL as a floating-point number of length LEN to a + target-order byte-stream at ADDR. */ + +void +store_floating (void *addr, int len, DOUBLEST val) +{ + const struct floatformat *fmt = floatformat_from_length (len); + + if (fmt == NULL) + { + warning ("Can't store a floating-point number of %d bytes.", len); + memset (addr, 0, len); + } + + floatformat_from_doublest (fmt, &val, addr); +} + +/* Extract a floating-point number of type TYPE from a target-order + byte-stream at ADDR. Returns the value as type DOUBLEST. */ + +DOUBLEST +extract_typed_floating (const void *addr, const struct type *type) +{ + DOUBLEST retval; + + gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); + + if (TYPE_FLOATFORMAT (type) == NULL) + return extract_floating (addr, TYPE_LENGTH (type)); + + floatformat_to_doublest (TYPE_FLOATFORMAT (type), addr, &retval); + return retval; +} + +/* Store VAL as a floating-point number of type TYPE to a target-order + byte-stream at ADDR. */ + +void +store_typed_floating (void *addr, const struct type *type, DOUBLEST val) +{ + gdb_assert (TYPE_CODE (type) == TYPE_CODE_FLT); + + /* FIXME: kettenis/2001-10-28: It is debatable whether we should + zero out any remaining bytes in the target buffer when TYPE is + longer than the actual underlying floating-point format. Perhaps + we should store a fixed bitpattern in those remaining bytes, + instead of zero, or perhaps we shouldn't touch those remaining + bytes at all. + + NOTE: cagney/2001-10-28: With the way things currently work, it + isn't a good idea to leave the end bits undefined. This is + because GDB writes out the entire sizeof(<floating>) bits of the + floating-point type even though the value might only be stored + in, and the target processor may only refer to, the first N < + TYPE_LENGTH (type) bits. If the end of the buffer wasn't + initialized, GDB would write undefined data to the target. An + errant program, refering to that undefined data, would then + become non-deterministic. + + See also the function convert_typed_floating below. */ + memset (addr, 0, TYPE_LENGTH (type)); + + if (TYPE_FLOATFORMAT (type) == NULL) + store_floating (addr, TYPE_LENGTH (type), val); + else + floatformat_from_doublest (TYPE_FLOATFORMAT (type), &val, addr); +} + +/* Convert a floating-point number of type FROM_TYPE from a + target-order byte-stream at FROM to a floating-point number of type + TO_TYPE, and store it to a target-order byte-stream at TO. */ + +void +convert_typed_floating (const void *from, const struct type *from_type, + void *to, const struct type *to_type) +{ + const struct floatformat *from_fmt = floatformat_from_type (from_type); + const struct floatformat *to_fmt = floatformat_from_type (to_type); + + gdb_assert (TYPE_CODE (from_type) == TYPE_CODE_FLT); + gdb_assert (TYPE_CODE (to_type) == TYPE_CODE_FLT); + + if (from_fmt == NULL || to_fmt == NULL) + { + /* If we don't know the floating-point format of FROM_TYPE or + TO_TYPE, there's not much we can do. We might make the + assumption that if the length of FROM_TYPE and TO_TYPE match, + their floating-point format would match too, but that + assumption might be wrong on targets that support + floating-point types that only differ in endianness for + example. So we warn instead, and zero out the target buffer. */ + warning ("Can't convert floating-point number to desired type."); + memset (to, 0, TYPE_LENGTH (to_type)); + } + else if (from_fmt == to_fmt) + { + /* We're in business. The floating-point format of FROM_TYPE + and TO_TYPE match. However, even though the floating-point + format matches, the length of the type might still be + different. Make sure we don't overrun any buffers. See + comment in store_typed_floating for a discussion about + zeroing out remaining bytes in the target buffer. */ + memset (to, 0, TYPE_LENGTH (to_type)); + memcpy (to, from, min (TYPE_LENGTH (from_type), TYPE_LENGTH (to_type))); + } + else + { + /* The floating-point types don't match. The best we can do + (aport from simulating the target FPU) is converting to the + widest floating-point type supported by the host, and then + again to the desired type. */ + DOUBLEST d; + + floatformat_to_doublest (from_fmt, from, &d); + floatformat_from_doublest (to_fmt, &d, to); + } +} |