diff options
Diffstat (limited to 'sysdeps/arm')
| -rw-r--r-- | sysdeps/arm/fpu/fpu_control.h | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/sysdeps/arm/fpu/fpu_control.h b/sysdeps/arm/fpu/fpu_control.h index b5338c5755..dfcfaabfcd 100644 --- a/sysdeps/arm/fpu/fpu_control.h +++ b/sysdeps/arm/fpu/fpu_control.h @@ -1,5 +1,5 @@ /* FPU control word definitions. ARM version. - Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc. + Copyright (C) 1996, 1997, 1998, 2000 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 @@ -23,12 +23,12 @@ /* We have a slight terminology confusion here. On the ARM, the register * we're interested in is actually the FPU status word - the FPU control * word is something different (which is implementation-defined and only - * accessible from supervisor mode.) + * accessible from supervisor mode.) * * The FPSR looks like this: * * 31-24 23-16 15-8 7-0 - * | system ID | trap enable | system control | exception flags | + * | system ID | trap enable | system control | exception flags | * * We ignore the system ID bits; for interest's sake they are: * @@ -40,7 +40,7 @@ * The trap enable and exception flags are both structured like this: * * 7 - 5 4 3 2 1 0 - * | reserved | INX | UFL | OFL | DVZ | IVO | + * | reserved | INX | UFL | OFL | DVZ | IVO | * * where a `1' bit in the enable byte means that the trap can occur, and * a `1' bit in the flags byte means the exception has occurred. @@ -57,7 +57,7 @@ * * 7-5 4 3 2 1 0 * | reserved | AC | EP | SO | NE | ND | - * + * * where the bits mean * * ND - no denormalised numbers (force them all to zero) @@ -67,11 +67,27 @@ * AC - use alternate definition for C flag on compare operations */ -#define _FPU_RESERVED 0xfff0e0f0 /* These bits are reserved. */ +/* masking of interrupts */ +#define _FPU_MASK_IM 0x00010000 /* invalid operation */ +#define _FPU_MASK_ZM 0x00020000 /* divide by zero */ +#define _FPU_MASK_OM 0x00040000 /* overflow */ +#define _FPU_MASK_UM 0x00080000 /* underflow */ +#define _FPU_MASK_PM 0x00100000 /* inexact */ +#define _FPU_MASK_DM 0x00000000 /* denormalized operation */ + +/* The system id bytes cannot be changed. + Only the bottom 5 bits in the trap enable byte can be changed. + Only the bottom 5 bits in the system control byte can be changed. + Only the bottom 5 bits in the exception flags are used. + The exception flags are set by the fpu, but can be zeroed by the user. */ +#define _FPU_RESERVED 0xffe0e0e0 /* These bits are reserved. */ -/* The fdlibm code requires no interrupts for exceptions. Don't - change the rounding mode, it would break long double I/O! */ -#define _FPU_DEFAULT 0x00001000 /* Default value. */ +/* The fdlibm code requires strict IEEE double precision arithmetic, + no interrupts for exceptions, rounding to nearest. Changing the + rounding mode will break long double I/O. Turn on the AC bit, + the compiler generates code that assumes it is on. */ +#define _FPU_DEFAULT 0x00001000 /* Default value. */ +#define _FPU_IEEE 0x001f1000 /* Default + exceptions enabled. */ /* Type of the control word. */ typedef unsigned int fpu_control_t; |