diff options
Diffstat (limited to 'gdb/target-float.c')
| -rw-r--r-- | gdb/target-float.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/gdb/target-float.c b/gdb/target-float.c index 8f1b9f6..32237ec 100644 --- a/gdb/target-float.c +++ b/gdb/target-float.c @@ -1142,6 +1142,569 @@ host_float_ops<T>::compare (const gdb_byte *x, const struct type *type_x, } +/* Implementation of target_float_ops using the MPFR library + mpfr_t as intermediate type. */ + +#ifdef HAVE_LIBMPFR + +#include <mpfr.h> + +class mpfr_float_ops : public target_float_ops +{ +public: + std::string to_string (const gdb_byte *addr, const struct type *type, + const char *format) const override; + bool from_string (gdb_byte *addr, const struct type *type, + const std::string &string) const override; + + LONGEST to_longest (const gdb_byte *addr, + const struct type *type) const override; + void from_longest (gdb_byte *addr, const struct type *type, + LONGEST val) const override; + void from_ulongest (gdb_byte *addr, const struct type *type, + ULONGEST val) const override; + double to_host_double (const gdb_byte *addr, + const struct type *type) const override; + void from_host_double (gdb_byte *addr, const struct type *type, + double val) const override; + void convert (const gdb_byte *from, const struct type *from_type, + gdb_byte *to, const struct type *to_type) const override; + + void binop (enum exp_opcode opcode, + const gdb_byte *x, const struct type *type_x, + const gdb_byte *y, const struct type *type_y, + gdb_byte *res, const struct type *type_res) const override; + int compare (const gdb_byte *x, const struct type *type_x, + const gdb_byte *y, const struct type *type_y) const override; + +private: + /* Local wrapper class to handle mpfr_t initalization and cleanup. */ + class gdb_mpfr + { + public: + mpfr_t val; + + gdb_mpfr (const struct type *type) + { + const struct floatformat *fmt = floatformat_from_type (type); + mpfr_init2 (val, floatformat_precision (fmt)); + } + + gdb_mpfr (const gdb_mpfr &source) + { + mpfr_init2 (val, mpfr_get_prec (source.val)); + } + + ~gdb_mpfr () + { + mpfr_clear (val); + } + }; + + void from_target (const struct floatformat *fmt, + const gdb_byte *from, gdb_mpfr &to) const; + void from_target (const struct type *type, + const gdb_byte *from, gdb_mpfr &to) const; + + void to_target (const struct type *type, + const gdb_mpfr &from, gdb_byte *to) const; + void to_target (const struct floatformat *fmt, + const gdb_mpfr &from, gdb_byte *to) const; +}; + + +/* Convert TO/FROM target floating-point format to mpfr_t. */ + +void +mpfr_float_ops::from_target (const struct floatformat *fmt, + const gdb_byte *orig_from, gdb_mpfr &to) const +{ + const gdb_byte *from = orig_from; + mpfr_exp_t exponent; + unsigned long mant; + unsigned int mant_bits, mant_off; + int mant_bits_left; + int special_exponent; /* It's a NaN, denorm or zero. */ + enum floatformat_byteorders order; + unsigned char newfrom[FLOATFORMAT_LARGEST_BYTES]; + enum float_kind kind; + + gdb_assert (fmt->totalsize + <= FLOATFORMAT_LARGEST_BYTES * FLOATFORMAT_CHAR_BIT); + + /* Handle non-numbers. */ + kind = floatformat_classify (fmt, from); + if (kind == float_infinite) + { + mpfr_set_inf (to.val, floatformat_is_negative (fmt, from) ? -1 : 1); + return; + } + if (kind == float_nan) + { + mpfr_set_nan (to.val); + return; + } + + order = floatformat_normalize_byteorder (fmt, from, newfrom); + + if (order != fmt->byteorder) + from = newfrom; + + if (fmt->split_half) + { + gdb_mpfr top (to), bot (to); + + from_target (fmt->split_half, from, top); + /* Preserve the sign of 0, which is the sign of the top half. */ + if (mpfr_zero_p (top.val)) + { + mpfr_set (to.val, top.val, MPFR_RNDN); + return; + } + from_target (fmt->split_half, + from + fmt->totalsize / FLOATFORMAT_CHAR_BIT / 2, bot); + mpfr_add (to.val, top.val, bot.val, MPFR_RNDN); + return; + } + + exponent = get_field (from, order, 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; + mpfr_set_zero (to.val, 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. + Note the cast to int; exp_bias is unsigned, so it's important to + make sure the operation is done in signed arithmetic. */ + 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) + mpfr_set_ui_2exp (to.val, 1, exponent, MPFR_RNDN); + else + exponent++; + } + + gdb_mpfr tmp (to); + + while (mant_bits_left > 0) + { + mant_bits = std::min (mant_bits_left, 32); + + mant = get_field (from, order, fmt->totalsize, mant_off, mant_bits); + + mpfr_set_si (tmp.val, mant, MPFR_RNDN); + mpfr_mul_2si (tmp.val, tmp.val, exponent - mant_bits, MPFR_RNDN); + mpfr_add (to.val, to.val, tmp.val, MPFR_RNDN); + exponent -= mant_bits; + mant_off += mant_bits; + mant_bits_left -= mant_bits; + } + + /* Negate it if negative. */ + if (get_field (from, order, fmt->totalsize, fmt->sign_start, 1)) + mpfr_neg (to.val, to.val, MPFR_RNDN); +} + +void +mpfr_float_ops::from_target (const struct type *type, + const gdb_byte *from, gdb_mpfr &to) const +{ + from_target (floatformat_from_type (type), from, to); +} + +void +mpfr_float_ops::to_target (const struct floatformat *fmt, + const gdb_mpfr &from, gdb_byte *orig_to) const +{ + unsigned char *to = orig_to; + mpfr_exp_t exponent; + unsigned int mant_bits, mant_off; + int mant_bits_left; + enum floatformat_byteorders order = fmt->byteorder; + unsigned char newto[FLOATFORMAT_LARGEST_BYTES]; + + if (order != floatformat_little) + order = floatformat_big; + + if (order != fmt->byteorder) + to = newto; + + memset (to, 0, floatformat_totalsize_bytes (fmt)); + + if (fmt->split_half) + { + gdb_mpfr top (from), bot (from); + + mpfr_set (top.val, from.val, MPFR_RNDN); + /* If the rounded top half is Inf, the bottom must be 0 not NaN + or Inf. */ + if (mpfr_inf_p (top.val)) + mpfr_set_zero (bot.val, 0); + else + mpfr_sub (bot.val, from.val, top.val, MPFR_RNDN); + + to_target (fmt->split_half, top, to); + to_target (fmt->split_half, bot, + to + fmt->totalsize / FLOATFORMAT_CHAR_BIT / 2); + return; + } + + gdb_mpfr tmp (from); + + if (mpfr_zero_p (from.val)) + goto finalize_byteorder; /* Result is zero */ + + mpfr_set (tmp.val, from.val, MPFR_RNDN); + + if (mpfr_nan_p (tmp.val)) /* Result is NaN */ + { + /* From is NaN */ + put_field (to, order, fmt->totalsize, fmt->exp_start, + fmt->exp_len, fmt->exp_nan); + /* Be sure it's not infinity, but NaN value is irrel. */ + put_field (to, order, fmt->totalsize, fmt->man_start, + fmt->man_len, 1); + goto finalize_byteorder; + } + + /* If negative, set the sign bit. */ + if (mpfr_sgn (tmp.val) < 0) + { + put_field (to, order, fmt->totalsize, fmt->sign_start, 1, 1); + mpfr_neg (tmp.val, tmp.val, MPFR_RNDN); + } + + if (mpfr_inf_p (tmp.val)) /* Result is Infinity. */ + { + /* Infinity exponent is same as NaN's. */ + put_field (to, order, fmt->totalsize, fmt->exp_start, + fmt->exp_len, fmt->exp_nan); + /* Infinity mantissa is all zeroes. */ + put_field (to, order, fmt->totalsize, fmt->man_start, + fmt->man_len, 0); + goto finalize_byteorder; + } + + mpfr_frexp (&exponent, tmp.val, tmp.val, MPFR_RNDN); + + if (exponent + fmt->exp_bias <= 0) + { + /* The value is too small to be expressed in the destination + type (not enough bits in the exponent. Treat as 0. */ + put_field (to, order, fmt->totalsize, fmt->exp_start, + fmt->exp_len, 0); + put_field (to, order, fmt->totalsize, fmt->man_start, + fmt->man_len, 0); + goto finalize_byteorder; + } + + if (exponent + fmt->exp_bias >= (1 << fmt->exp_len)) + { + /* The value is too large to fit into the destination. + Treat as infinity. */ + put_field (to, order, fmt->totalsize, fmt->exp_start, + fmt->exp_len, fmt->exp_nan); + put_field (to, order, fmt->totalsize, fmt->man_start, + fmt->man_len, 0); + goto finalize_byteorder; + } + + put_field (to, order, 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; + + mpfr_mul_2ui (tmp.val, tmp.val, 32, MPFR_RNDN); + mant_long = mpfr_get_ui (tmp.val, MPFR_RNDZ) & 0xffffffffL; + mpfr_sub_ui (tmp.val, tmp.val, mant_long, MPFR_RNDZ); + + /* 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; + /* If we are processing the top 32 mantissa bits of a doublest + so as to convert to a float value with implied integer bit, + we will only be putting 31 of those 32 bits into the + final value due to the discarding of the top bit. In the + case of a small float value where the number of mantissa + bits is less than 32, discarding the top bit does not alter + the number of bits we will be adding to the result. */ + if (mant_bits == 32) + 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 (to, order, fmt->totalsize, + mant_off, mant_bits, mant_long); + mant_off += mant_bits; + mant_bits_left -= mant_bits; + } + + finalize_byteorder: + /* Do we need to byte-swap the words in the result? */ + if (order != fmt->byteorder) + floatformat_normalize_byteorder (fmt, newto, orig_to); +} + +void +mpfr_float_ops::to_target (const struct type *type, + const gdb_mpfr &from, gdb_byte *to) const +{ + /* Ensure possible padding bytes in the target buffer are zeroed out. */ + memset (to, 0, TYPE_LENGTH (type)); + + to_target (floatformat_from_type (type), from, to); +} + +/* Convert the byte-stream ADDR, interpreted as floating-point type TYPE, + to a string, optionally using the print format FORMAT. */ +std::string +mpfr_float_ops::to_string (const gdb_byte *addr, + const struct type *type, + const char *format) const +{ + const struct floatformat *fmt = floatformat_from_type (type); + + /* Unless we need to adhere to a specific format, provide special + output for certain cases. */ + if (format == nullptr) + { + /* Detect invalid representations. */ + if (!floatformat_is_valid (fmt, addr)) + return "<invalid float value>"; + + /* Handle NaN and Inf. */ + enum float_kind kind = floatformat_classify (fmt, addr); + if (kind == float_nan) + { + const char *sign = floatformat_is_negative (fmt, addr)? "-" : ""; + const char *mantissa = floatformat_mantissa (fmt, addr); + return string_printf ("%snan(0x%s)", sign, mantissa); + } + else if (kind == float_infinite) + { + const char *sign = floatformat_is_negative (fmt, addr)? "-" : ""; + return string_printf ("%sinf", sign); + } + } + + /* Determine the format string to use on the host side. */ + std::string host_format = floatformat_printf_format (fmt, format, 'R'); + + gdb_mpfr tmp (type); + from_target (type, addr, tmp); + + int size = mpfr_snprintf (NULL, 0, host_format.c_str (), tmp.val); + std::string str (size, '\0'); + mpfr_sprintf (&str[0], host_format.c_str (), tmp.val); + + return str; +} + +/* Parse string STRING into a target floating-number of type TYPE and + store it as byte-stream ADDR. Return whether parsing succeeded. */ +bool +mpfr_float_ops::from_string (gdb_byte *addr, + const struct type *type, + const std::string &in) const +{ + gdb_mpfr tmp (type); + + char *endptr; + mpfr_strtofr (tmp.val, in.c_str (), &endptr, 0, MPFR_RNDN); + + /* We only accept the whole string. */ + if (*endptr) + return false; + + to_target (type, tmp, addr); + return true; +} + +/* Convert the byte-stream ADDR, interpreted as floating-point type TYPE, + to an integer value (rounding towards zero). */ +LONGEST +mpfr_float_ops::to_longest (const gdb_byte *addr, + const struct type *type) const +{ + gdb_mpfr tmp (type); + from_target (type, addr, tmp); + return mpfr_get_sj (tmp.val, MPFR_RNDZ); +} + +/* Convert signed integer VAL to a target floating-number of type TYPE + and store it as byte-stream ADDR. */ +void +mpfr_float_ops::from_longest (gdb_byte *addr, + const struct type *type, + LONGEST val) const +{ + gdb_mpfr tmp (type); + mpfr_set_sj (tmp.val, val, MPFR_RNDN); + to_target (type, tmp, addr); +} + +/* Convert unsigned integer VAL to a target floating-number of type TYPE + and store it as byte-stream ADDR. */ +void +mpfr_float_ops::from_ulongest (gdb_byte *addr, + const struct type *type, + ULONGEST val) const +{ + gdb_mpfr tmp (type); + mpfr_set_uj (tmp.val, val, MPFR_RNDN); + to_target (type, tmp, addr); +} + +/* Convert the byte-stream ADDR, interpreted as floating-point type TYPE, + to a floating-point value in the host "double" format. */ +double +mpfr_float_ops::to_host_double (const gdb_byte *addr, + const struct type *type) const +{ + gdb_mpfr tmp (type); + from_target (type, addr, tmp); + return mpfr_get_d (tmp.val, MPFR_RNDN); +} + +/* Convert floating-point value VAL in the host "double" format to a target + floating-number of type TYPE and store it as byte-stream ADDR. */ +void +mpfr_float_ops::from_host_double (gdb_byte *addr, + const struct type *type, + double val) const +{ + gdb_mpfr tmp (type); + mpfr_set_d (tmp.val, val, MPFR_RNDN); + to_target (type, tmp, addr); +} + +/* Convert a floating-point number of type FROM_TYPE from the target + byte-stream FROM to a floating-point number of type TO_TYPE, and + store it to the target byte-stream TO. */ +void +mpfr_float_ops::convert (const gdb_byte *from, + const struct type *from_type, + gdb_byte *to, + const struct type *to_type) const +{ + gdb_mpfr from_tmp (from_type), to_tmp (to_type); + from_target (from_type, from, from_tmp); + mpfr_set (to_tmp.val, from_tmp.val, MPFR_RNDN); + to_target (to_type, to_tmp, to); +} + +/* Perform the binary operation indicated by OPCODE, using as operands the + target byte streams X and Y, interpreted as floating-point numbers of + types TYPE_X and TYPE_Y, respectively. Convert the result to type + TYPE_RES and store it into the byte-stream RES. */ +void +mpfr_float_ops::binop (enum exp_opcode op, + const gdb_byte *x, const struct type *type_x, + const gdb_byte *y, const struct type *type_y, + gdb_byte *res, const struct type *type_res) const +{ + gdb_mpfr x_tmp (type_x), y_tmp (type_y), tmp (type_res); + + from_target (type_x, x, x_tmp); + from_target (type_y, y, y_tmp); + + switch (op) + { + case BINOP_ADD: + mpfr_add (tmp.val, x_tmp.val, y_tmp.val, MPFR_RNDN); + break; + + case BINOP_SUB: + mpfr_sub (tmp.val, x_tmp.val, y_tmp.val, MPFR_RNDN); + break; + + case BINOP_MUL: + mpfr_mul (tmp.val, x_tmp.val, y_tmp.val, MPFR_RNDN); + break; + + case BINOP_DIV: + mpfr_div (tmp.val, x_tmp.val, y_tmp.val, MPFR_RNDN); + break; + + case BINOP_EXP: + mpfr_pow (tmp.val, x_tmp.val, y_tmp.val, MPFR_RNDN); + break; + + case BINOP_MIN: + mpfr_min (tmp.val, x_tmp.val, y_tmp.val, MPFR_RNDN); + break; + + case BINOP_MAX: + mpfr_max (tmp.val, x_tmp.val, y_tmp.val, MPFR_RNDN); + break; + + default: + error (_("Integer-only operation on floating point number.")); + break; + } + + to_target (type_res, tmp, res); +} + +/* Compare the two target byte streams X and Y, interpreted as floating-point + numbers of types TYPE_X and TYPE_Y, respectively. Return zero if X and Y + are equal, -1 if X is less than Y, and 1 otherwise. */ +int +mpfr_float_ops::compare (const gdb_byte *x, const struct type *type_x, + const gdb_byte *y, const struct type *type_y) const +{ + gdb_mpfr x_tmp (type_x), y_tmp (type_y); + + from_target (type_x, x, x_tmp); + from_target (type_y, y, y_tmp); + + if (mpfr_equal_p (x_tmp.val, y_tmp.val)) + return 0; + else if (mpfr_less_p (x_tmp.val, y_tmp.val)) + return -1; + else + return 1; +} + +#endif + + /* Helper routines operating on decimal floating-point data. */ /* Decimal floating point is one of the extension to IEEE 754, which is @@ -1685,10 +2248,16 @@ get_target_float_ops (enum target_float_ops_kind kind) } /* For binary floating-point formats that do not match any host format, + use mpfr_t as intermediate format to provide precise target-floating + point emulation. However, if the MPFR library is not availabe, use the largest host floating-point type as intermediate format. */ case target_float_ops_kind::binary: { +#ifdef HAVE_LIBMPFR + static mpfr_float_ops binary_float_ops; +#else static host_float_ops<long double> binary_float_ops; +#endif return &binary_float_ops; } |