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Diffstat (limited to 'ports/sysdeps/m68k/fpu_control.h')
| -rw-r--r-- | ports/sysdeps/m68k/fpu_control.h | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/ports/sysdeps/m68k/fpu_control.h b/ports/sysdeps/m68k/fpu_control.h new file mode 100644 index 0000000000..98eb80ec49 --- /dev/null +++ b/ports/sysdeps/m68k/fpu_control.h @@ -0,0 +1,108 @@ +/* 68k FPU control word definitions. + Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + 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, see + <http://www.gnu.org/licenses/>. */ + +#ifndef _FPU_CONTROL_H +#define _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 (INEX on Coldfire) + * 8 -> enable trap for INEX1 exception (IDE on Coldfire) + * 7-6 -> Precision Control (only bit 6 is used on Coldfire) + * 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 */ +#ifdef __mcoldfire__ +#define _FPU_DOUBLE 0x00 +#else +#define _FPU_EXTENDED 0x00 /* RECOMMENDED */ +#define _FPU_DOUBLE 0x80 +#endif +#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 + +#ifdef __mcoldfire__ +#define _FPU_RESERVED 0xFFFF800F +#else +#define _FPU_RESERVED 0xFFFF000F /* Reserved bits in fpucr */ +#endif + + +/* Now two recommended fpucr */ + +/* The fdlibm code requires no interrupts for exceptions. Don't + change the rounding mode, it would break long double I/O! */ +#define _FPU_DEFAULT 0x00000000 + +/* 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 + +/* Type of the control word. */ +typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__))); + +/* Macros for accessing the hardware control word. */ +#define _FPU_GETCW(cw) __asm__ ("fmove%.l %!, %0" : "=dm" (cw)) +#define _FPU_SETCW(cw) __asm__ volatile ("fmove%.l %0, %!" : : "dm" (cw)) + +/* Default control word set at startup. */ +extern fpu_control_t __fpu_control; + +#endif /* _M68K_FPU_CONTROL_H */ |