1 .\" Copyright (c) 1993 Andrew Moore, Talke Studio
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32 .\" @(#)fpgetround.3 1.0 (Berkeley) 9/23/93
47 .Nd IEEE floating point interface
49 .Fd #include <ieeefp.h>
53 .Li /* round to nearest */
56 .Li /* round to minus infinity */
59 .Li /* round to plus infinity */
69 .Fn fpsetround "fp_rnd_t direction"
75 .Li /* 24 bit (single-precision) */
81 .Li /* 53 bit (double-precision) */
84 .Li /* 64 bit (extended-precision) */
91 .Fn fpsetprec "fp_prec_t precision"
93 .Fd #define fp_except_t int
94 .Fd #define FP_X_INV 0x01 /* invalid */
95 .Fd #define FP_X_OFL 0x08 /* overflow */
96 .Fd #define FP_X_UFL 0x10 /* underflow */
97 .Fd #define FP_X_DZ 0x04 /* divide-by-zero */
98 .Fd #define FP_X_IMP 0x20 /* loss of precision */
99 .Fd #define FP_X_DNML 0x02 /* denormal */
103 .Fn fpsetmask "fp_except_t mask"
107 .Fn fpresetsticky "fp_except_t sticky"
109 When a floating point exception is detected, the exception sticky flag is
110 set and the exception mask is tested. If the mask is set, then a trap
111 occurs. These routines allow both setting the floating point exception
112 masks, and resetting the exception sticky flags after an exception is
113 detected. In addition, they allow setting the floating point rounding mode
119 returns the current floating point rounding mode.
124 sets the floating point rounding mode and returns
130 returns the current floating point precision.
135 sets the floating point precision and returns
136 the previous precision.
141 returns the current floating point exception masks.
146 sets the floating point exception masks and returns the
152 returns the current floating point sticky flags.
157 clears the floating point sticky flags and returns
160 Sample code which prevents a trap on divide-by-zero:
161 .Bd -literal -offset indent
166 fpresetsticky(FP_X_DZ);
172 After a floating point exception and before a mask is set, the sticky
173 flags must be reset. If another exception occurs before the sticky
174 flags are reset, then a wrong exception type may be signaled.
176 These routines are based on SysV/386 routines of the same name.