1 .\" Copyright (c) 1993 Andrew Moore, Talke Studio
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28 .\" @(#)fpgetround.3 1.0 (Berkeley) 9/23/93
29 .\" $FreeBSD: src/share/man/man3/fpgetround.3,v 1.20 2013/04/12 00:37:30 svnexp Exp $
42 .Nd IEEE floating point interface
49 FP_RN, /* round to nearest */
50 FP_RM, /* round down to minus infinity */
51 FP_RP, /* round up to plus infinity */
58 .Fn fpsetround "fp_rnd_t direction"
61 FP_PS, /* 24 bit (single-precision) */
62 FP_PRS, /* reserved */
63 FP_PD, /* 53 bit (double-precision) */
64 FP_PE /* 64 bit (extended-precision) */
70 .Fn fpsetprec "fp_prec_t precision"
72 #define fp_except_t int
73 #define FP_X_INV 0x01 /* invalid operation */
74 #define FP_X_DNML 0x02 /* denormal */
75 #define FP_X_DZ 0x04 /* zero divide */
76 #define FP_X_OFL 0x08 /* overflow */
77 #define FP_X_UFL 0x10 /* underflow */
78 #define FP_X_IMP 0x20 /* (im)precision */
79 #define FP_X_STK 0x40 /* stack fault */
84 .Fn fpsetmask "fp_except_t mask"
88 The routines described herein are deprecated.
89 New code should use the functionality provided by
92 When a floating point exception is detected, the exception sticky flag is
93 set and the exception mask is tested.
94 If the mask is set, then a trap occurs.
95 These routines allow both setting the floating point exception
96 masks, and resetting the exception sticky flags after an exception is
98 In addition, they allow setting the floating point rounding mode
104 returns the current floating point rounding mode.
109 sets the floating point rounding mode and returns
115 returns the current floating point precision.
120 sets the floating point precision and returns
121 the previous precision.
126 returns the current floating point exception masks.
131 sets the floating point exception masks and returns the
137 returns the current floating point sticky flags.
138 .Sh IMPLEMENTATION NOTES
143 functions provide functionality unavailable on many platforms.
144 At present, they are implemented only on the x86_64 platform.
145 Changing precision is not a supported feature:
146 it may be ineffective when code is compiled to take advantage of SSE,
147 and many library functions and compiler optimizations depend upon the
148 default precision for correct behavior.
153 These routines are based on SysV/386 routines of the same name.
155 After a floating point exception and before a mask is set, the sticky
157 If another exception occurs before the sticky
158 flags are reset, then a wrong exception type may be signaled.