/* FPU control word bits. Alpha-mapped-to-Intel version. Copyright (C) 1996, 1998, 2000, 2002 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Olaf Flebbe. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. */ #ifndef _ALPHA_FPU_CONTROL_H #define _ALPHA_FPU_CONTROL_H /* * Since many programs seem to hardcode the values passed to __setfpucw() * (rather than using the manifest constants) we emulate the x87 interface * here (at least where this makes sense). * * 15-13 12 11-10 9-8 7-6 5 4 3 2 1 0 * | reserved | IC | RC | PC | reserved | PM | UM | OM | ZM | DM | IM * * IM: Invalid operation mask * DM: Denormalized operand mask * ZM: Zero-divide mask * OM: Overflow mask * UM: Underflow mask * PM: Precision (inexact result) mask * * Mask bit is 1 means no interrupt. * * PC: Precision control * 11 - round to extended precision * 10 - round to double precision * 00 - round to single precision * * RC: Rounding control * 00 - rounding to nearest * 01 - rounding down (toward - infinity) * 10 - rounding up (toward + infinity) * 11 - rounding toward zero * * IC: Infinity control * That is for 8087 and 80287 only. * * The hardware default is 0x037f. I choose 0x1372. */ #include <features.h> /* masking of interrupts */ #define _FPU_MASK_IM 0x01 #define _FPU_MASK_DM 0x02 #define _FPU_MASK_ZM 0x04 #define _FPU_MASK_OM 0x08 #define _FPU_MASK_UM 0x10 #define _FPU_MASK_PM 0x20 /* precision control -- without effect on Alpha */ #define _FPU_EXTENDED 0x300 /* RECOMMENDED */ #define _FPU_DOUBLE 0x200 #define _FPU_SINGLE 0x0 /* DO NOT USE */ /* * rounding control---notice that on the Alpha this affects only * instructions with the dynamic rounding mode qualifier (/d). */ #define _FPU_RC_NEAREST 0x000 /* RECOMMENDED */ #define _FPU_RC_DOWN 0x400 #define _FPU_RC_UP 0x800 #define _FPU_RC_ZERO 0xC00 #define _FPU_RESERVED 0xF0C0 /* Reserved bits in cw */ /* Now two recommended cw */ /* Linux default: - extended precision - rounding to positive infinity. There is no /p instruction qualifier. By setting the dynamic rounding mode to +infinity, one can use /d to get round to +infinity with no extra overhead (so long as the default isn't changed, of course...) - no exceptions enabled. */ #define _FPU_DEFAULT 0x137f /* IEEE: same as above. */ #define _FPU_IEEE 0x137f /* Type of the control word. */ typedef unsigned int fpu_control_t; #if 0 /* Default control word set at startup. */ extern fpu_control_t __fpu_control; #endif #endif /* _ALPHA_FPU_CONTROL */