| /* IEEE floating point support routines, for GDB, the GNU Debugger. |
| Copyright (C) 1991-2021 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., 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 <math.h> |
| |
| #ifdef HAVE_STRING_H |
| #include <string.h> |
| #endif |
| |
| /* On some platforms, <float.h> provides DBL_QNAN. */ |
| #ifdef STDC_HEADERS |
| #include <float.h> |
| #endif |
| |
| #include "ansidecl.h" |
| #include "libiberty.h" |
| #include "floatformat.h" |
| |
| #ifndef INFINITY |
| #ifdef HUGE_VAL |
| #define INFINITY HUGE_VAL |
| #else |
| #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 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_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_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_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_always_valid, |
| NULL |
| }; |
| |
| /* 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_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_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_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_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_always_valid, |
| NULL |
| }; |
| const struct floatformat floatformat_m88110_harris_ext = |
| { |
| /* 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", |
| 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_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_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_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_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_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_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 |
| }; |
| |
| const struct floatformat floatformat_bfloat16_big = |
| { |
| floatformat_big, 16, 0, 1, 8, 127, 255, 9, 7, |
| floatformat_intbit_no, |
| "floatformat_bfloat16_big", |
| floatformat_always_valid, |
| NULL |
| }; |
| |
| const struct floatformat floatformat_bfloat16_little = |
| { |
| floatformat_little, 16, 0, 1, 8, 127, 255, 9, 7, |
| floatformat_intbit_no, |
| "floatformat_bfloat16_little", |
| floatformat_always_valid, |
| NULL |
| }; |
| |
| #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 (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 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. */ |
| if (order == floatformat_little) |
| cur_byte = start / FLOATFORMAT_CHAR_BIT; |
| else |
| cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; |
| |
| lo_bit = start % FLOATFORMAT_CHAR_BIT; |
| hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); |
| |
| do |
| { |
| 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; |
| } |
| |
| /* Convert from FMT to a double. |
| FROM is the address of the extended float. |
| Store the double in *TO. */ |
| |
| void |
| floatformat_to_double (const struct floatformat *fmt, |
| const void *from, double *to) |
| { |
| 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; |
| |
| /* 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); |
| |
| /* 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; |
| |
| /* Build the result algebraically. Might go infinite, underflow, etc; |
| who cares. */ |
| |
| /* 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 |
| 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 bits 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 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. */ |
| if (order == floatformat_little) |
| cur_byte = start / FLOATFORMAT_CHAR_BIT; |
| else |
| cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; |
| |
| lo_bit = start % FLOATFORMAT_CHAR_BIT; |
| hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); |
| |
| do |
| { |
| 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 |
| and store where TO points. Neither FROM nor TO have any alignment |
| restrictions. */ |
| |
| void |
| 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; |
| |
| 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) |
| { |
| /* 0.0. */ |
| return; |
| } |
| |
| if (dfrom != dfrom) |
| { |
| /* 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 irrelevant. */ |
| put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, |
| 32, 1); |
| return; |
| } |
| |
| if (dfrom + 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; |
| } |
| |
| mant = frexp (dfrom, &exponent); |
| 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; |
| 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, 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 |
| && exponent + fmt->exp_bias - 1 > 0) |
| { |
| 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; |
| } |
| } |
| |
| /* Return non-zero iff the data at FROM is a valid number in format FMT. */ |
| |
| int |
| floatformat_is_valid (const struct floatformat *fmt, const void *from) |
| { |
| return fmt->is_valid (fmt, from); |
| } |
| |
| |
| #ifdef IEEE_DEBUG |
| |
| #include <stdio.h> |
| |
| /* This is to be run on a host which uses IEEE floating point. */ |
| |
| void |
| ieee_test (double n) |
| { |
| double 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_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); |
| |
| #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. */ |
| { |
| long double ex = *(long double *)exten; |
| if (ex != n) |
| printf ("Differ(from vs. extended): %.20g\n", n); |
| } |
| #endif |
| } |
| |
| int |
| 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 |