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glibc  2.9
fpu_control.h
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00001 /* FPU control word definitions.  PowerPC version.
00002    Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #ifndef _FPU_CONTROL_H
00021 #define _FPU_CONTROL_H
00022 
00023 /* rounding control */
00024 #define _FPU_RC_NEAREST 0x00   /* RECOMMENDED */
00025 #define _FPU_RC_DOWN    0x03
00026 #define _FPU_RC_UP      0x02
00027 #define _FPU_RC_ZERO    0x01
00028 
00029 #define _FPU_MASK_NI  0x04 /* non-ieee mode */
00030 
00031 /* masking of interrupts */
00032 #define _FPU_MASK_ZM  0x10 /* zero divide */
00033 #define _FPU_MASK_OM  0x40 /* overflow */
00034 #define _FPU_MASK_UM  0x20 /* underflow */
00035 #define _FPU_MASK_XM  0x08 /* inexact */
00036 #define _FPU_MASK_IM  0x80 /* invalid operation */
00037 
00038 #define _FPU_RESERVED 0xffffff00 /* These bits are reserved are not changed. */
00039 
00040 /* The fdlibm code requires no interrupts for exceptions.  */
00041 #define _FPU_DEFAULT  0x00000000 /* Default value.  */
00042 
00043 /* IEEE:  same as above, but (some) exceptions;
00044    we leave the 'inexact' exception off.
00045  */
00046 #define _FPU_IEEE     0x000000f0
00047 
00048 /* Type of the control word.  */
00049 typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
00050 
00051 /* Macros for accessing the hardware control word.  */
00052 #define _FPU_GETCW(__cw) ( { \
00053   union { double d; fpu_control_t cw[2]; } \
00054     tmp __attribute__ ((__aligned__(8))); \
00055   __asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0"); \
00056   (__cw)=tmp.cw[1]; \
00057   tmp.cw[1]; } )
00058 #define _FPU_SETCW(__cw) { \
00059   union { double d; fpu_control_t cw[2]; } \
00060     tmp __attribute__ ((__aligned__(8))); \
00061   tmp.cw[0] = 0xFFF80000; /* More-or-less arbitrary; this is a QNaN. */ \
00062   tmp.cw[1] = __cw; \
00063   __asm__ ("lfd%U0 0,%0; mtfsf 255,0" : : "m" (tmp.d) : "fr0"); \
00064 }
00065 
00066 /* Default control word set at startup.  */
00067 extern fpu_control_t __fpu_control;
00068 
00069 #endif /* _FPU_CONTROL_H */