NAME

floatingpoint − IEEE floating point definitions

SYNOPSIS

#include <sys/ieeefp.h>
#include <floatingpoint.h>

DESCRIPTION

This file defines constants, types, variables, and functions used to implement standard floating point according to ANSI/IEEE Std 754-1985.  The variables and functions are implemented in libc.a.  The included file <sys/ieeefp.h> defines certain types of interest to the kernel. 

IEEE Rounding Modes:

fp_direction_type The type of the IEEE rounding direction mode.  Note: the order of enumeration varies according to hardware. 

fp_direction The IEEE rounding direction mode currently in force.  This is a global variable that is intended to reflect the hardware state, so it should only be written indirectly through a function like ieee_flags(set,direction,...)" " " " " " that also sets the hardware state. 

fp_precision_type The type of the IEEE rounding precision mode, which only applies on systems that support extended precision such as Sun-3 systems with 68881’s. 

fp_precision The IEEE rounding precision mode currently in force.  This is a global variable that is intended to reflect the hardware state on systems with extended precision, so it should only be written indirectly through a function like ieee_flags("set","precision",...). 

SIGFPE handling:

sigfpe_code_type The type of a SIGFPE code. 

sigfpe_handler_type
The type of a user-definable SIGFPE exception handler called to handle a particular SIGFPE code. 

SIGFPE_DEFAULT A macro indicating the default SIGFPE exception handling, namely to perform the exception handling specified by calls to ieee_handler(3M), if any, and otherwise to dump core using abort(3). 

SIGFPE_IGNORE A macro indicating an alternate SIGFPE exception handling, namely to ignore and continue execution. 

SIGFPE_ABORT A macro indicating an alternate SIGFPE exception handling, namely to abort with a core dump. 

IEEE Exception Handling:

N_IEEE_EXCEPTION
The number of distinct IEEE floating-point exceptions. 

fp_exception_type The type of the N_IEEE_EXCEPTION exceptions.  Each exception is given a bit number. 

fp_exception_field_type
The type intended to hold at least N_IEEE_EXCEPTION bits corresponding to the IEEE exceptions numbered by fp_exception_type.  Thus fp_inexact corresponds to the least significant bit and fp_invalid to the fifth least significant bit.  Note: some operations may set more than one exception. 

fp_accrued_exceptions
The IEEE exceptions between the time this global variable was last cleared, and the last time a function like ieee_flags("get","exception",...) was called to update the variable by obtaining the hardware state. 

ieee_handlers An array of user-specifiable signal handlers for use by the standard SIGFPE handler for IEEE arithmetic-related SIGFPE codes.  Since IEEE trapping modes correspond to hardware modes, elements of this array should only be modified with a function like ieee_handler(3M) that performs the appropriate hardware mode update.  If no sigfpe_handler has been declared for a particular IEEE-related SIGFPE code, then the related ieee_handlers will be invoked. 

IEEE Formats and Classification:

single;extended Definitions of IEEE formats. 

fp_class_type An enumeration of the various classes of IEEE values and symbols. 

IEEE Base Conversion:

The functions described under floating_to_decimal(3) and decimal_to_floating(3) not only satisfy the IEEE Standard, but also the stricter requirements of correct rounding for all arguments. 

DECIMAL_STRING_LENGTH
The length of a decimal_string. 

decimal_string The digit buffer in a decimal_record. 

decimal_record The canonical form for representing an unpacked decimal floating-point number. 

decimal_form The type used to specify fixed or floating binary to decimal conversion. 

decimal_mode A struct that contains specifications for conversion between binary and decimal. 

decimal_string_form
An enumeration of possible valid character strings representing floating-point numbers, infinities, or NaNs.

FILES

/usr/include/sys/ieeefp.h

/usr/include/floatingpoint.h

/usr/lib/libc.a

SEE ALSO

abort(3), decimal_to_floating(3), econvert(3), floating_to_decimal(3), ieee_flags(3M), ieee_handler(3M), sigfpe(3), string_to_decimal(3), strtod(3)

Sun Release 4.1  —  Last change: 21 October 1987