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[/] [or1k/] [trunk/] [uclinux/] [uC-libc/] [include/] [m68k/] [fpu_control.h] - Rev 1765
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/* Copyright (C) 1993 Olaf Flebbe This file is part of the Linux C Library. The Linux C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The Linux C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. */ #ifndef _M68K_FPU_CONTROL_H #define _M68K_FPU_CONTROL_H /* * Motorola floating point control register bits. * * 31-16 -> reserved (read as 0, ignored on write) * 15 -> enable trap for BSUN exception * 14 -> enable trap for SNAN exception * 13 -> enable trap for OPERR exception * 12 -> enable trap for OVFL exception * 11 -> enable trap for UNFL exception * 10 -> enable trap for DZ exception * 9 -> enable trap for INEX2 exception * 8 -> enable trap for INEX1 exception * 7-6 -> Precision Control * 5-4 -> Rounding Control * 3-0 -> zero (read as 0, write as 0) * * * Precision Control: * 00 - round to extended precision * 01 - round to single precision * 10 - round to double precision * 11 - undefined * * Rounding Control: * 00 - rounding to nearest (RN) * 01 - rounding toward zero (RZ) * 10 - rounding (down)toward minus infinity (RM) * 11 - rounding (up) toward plus infinity (RP) * * The hardware default is 0x0000. I choose 0x5400. */ #include <features.h> /* masking of interrupts */ #define _FPU_MASK_BSUN 0x8000 #define _FPU_MASK_SNAN 0x4000 #define _FPU_MASK_OPERR 0x2000 #define _FPU_MASK_OVFL 0x1000 #define _FPU_MASK_UNFL 0x0800 #define _FPU_MASK_DZ 0x0400 #define _FPU_MASK_INEX1 0x0200 #define _FPU_MASK_INEX2 0x0100 /* precision control */ #define _FPU_EXTENDED 0x00 /* RECOMMENDED */ #define _FPU_DOUBLE 0x80 #define _FPU_SINGLE 0x40 /* DO NOT USE */ /* rounding control */ #define _FPU_RC_NEAREST 0x00 /* RECOMMENDED */ #define _FPU_RC_ZERO 0x10 #define _FPU_RC_DOWN 0x20 #define _FPU_RC_UP 0x30 #define _FPU_RESERVED 0xFFFF000F /* Reserved bits in cw */ /* Now two recommended cw */ /* Linux default: - extended precision - rounding to nearest - exceptions on overflow, zero divide and NaN */ #if 0 #define _FPU_DEFAULT 0x00005400 #else /* Don't enable execptions any more. It caused too much grief. */ #define _FPU_DEFAULT 0x00000000 #endif /* IEEE: same as above, but exceptions. We must make it non-zero so that __setfpucw works. This bit will be ignored. */ #define _FPU_IEEE 0x00000001 /* private namespace. It should only be used by crt0.o. */ extern unsigned long __fpu_control; __BEGIN_DECLS /* called by crt0.o. It can be used to manipulate fpu control register. */ extern void __setfpucw __P ((unsigned long)); __END_DECLS #endif /* _M68K_FPU_CONTROL_H */