diff options
Diffstat (limited to 'libc/sysdeps/linux/m68k')
| -rw-r--r-- | libc/sysdeps/linux/m68k/fpu_control.h | 100 |
1 files changed, 67 insertions, 33 deletions
diff --git a/libc/sysdeps/linux/m68k/fpu_control.h b/libc/sysdeps/linux/m68k/fpu_control.h index 1b2ba87c9..484bad3b9 100644 --- a/libc/sysdeps/linux/m68k/fpu_control.h +++ b/libc/sysdeps/linux/m68k/fpu_control.h @@ -1,4 +1,4 @@ -/* FPU control word definitions. PowerPC version. +/* 68k FPU control word definitions. Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc. This file is part of the GNU C Library. @@ -20,50 +20,84 @@ #ifndef _FPU_CONTROL_H #define _FPU_CONTROL_H -/* rounding control */ -#define _FPU_RC_NEAREST 0x00 /* RECOMMENDED */ -#define _FPU_RC_DOWN 0x03 -#define _FPU_RC_UP 0x02 -#define _FPU_RC_ZERO 0x01 +/* + * 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. + */ -#define _FPU_MASK_NI 0x04 /* non-ieee mode */ +#include <features.h> /* masking of interrupts */ -#define _FPU_MASK_ZM 0x10 /* zero divide */ -#define _FPU_MASK_OM 0x40 /* overflow */ -#define _FPU_MASK_UM 0x20 /* underflow */ -#define _FPU_MASK_XM 0x08 /* inexact */ -#define _FPU_MASK_IM 0x80 /* invalid operation */ +#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 -#define _FPU_RESERVED 0xffffff00 /* These bits are reserved are not changed. */ +/* precision control */ +#define _FPU_EXTENDED 0x00 /* RECOMMENDED */ +#define _FPU_DOUBLE 0x80 +#define _FPU_SINGLE 0x40 /* DO NOT USE */ -/* The fdlibm code requires no interrupts for exceptions. */ -#define _FPU_DEFAULT 0x00000000 /* Default value. */ +/* rounding control */ +#define _FPU_RC_NEAREST 0x00 /* RECOMMENDED */ +#define _FPU_RC_ZERO 0x10 +#define _FPU_RC_DOWN 0x20 +#define _FPU_RC_UP 0x30 -/* IEEE: same as above, but (some) exceptions; - we leave the 'inexact' exception off. - */ -#define _FPU_IEEE 0x000000f0 +#define _FPU_RESERVED 0xFFFF000F /* Reserved bits in fpucr */ + + +/* 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) ( { \ - union { double d; fpu_control_t cw[2]; } \ - tmp __attribute__ ((__aligned__(8))); \ - __asm__ ("mffs 0; stfd%U0 0,%0" : "=m" (tmp.d) : : "fr0"); \ - (__cw)=tmp.cw[1]; \ - tmp.cw[1]; } ) -#define _FPU_SETCW(__cw) { \ - union { double d; fpu_control_t cw[2]; } \ - tmp __attribute__ ((__aligned__(8))); \ - tmp.cw[0] = 0xFFF80000; /* More-or-less arbitrary; this is a QNaN. */ \ - tmp.cw[1] = __cw; \ - __asm__ ("lfd%U0 0,%0; mtfsf 255,0" : : "m" (tmp.d) : "fr0"); \ -} +#define _FPU_GETCW(cw) __asm__ ("fmove%.l %!, %0" : "=dm" (cw)) +#define _FPU_SETCW(cw) __asm__ volatile ("fmove%.l %0, %!" : : "dm" (cw)) +#if 0 /* Default control word set at startup. */ extern fpu_control_t __fpu_control; +#endif -#endif /* _FPU_CONTROL_H */ +#endif /* _M68K_FPU_CONTROL_H */ |