Differential D26292 Diff 76576 sys/i386/include/ieeefp.h

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sys/i386/include/ieeefp.h

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	*			*
	* from: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93			* from: @(#) ieeefp.h 1.0 (Berkeley) 9/23/93
	* $FreeBSD$			* $FreeBSD$
	*/			*/

	#ifndef _MACHINE_IEEEFP_H_			#ifndef _MACHINE_IEEEFP_H_
	#define _MACHINE_IEEEFP_H_			#define _MACHINE_IEEEFP_H_

	/*			#include <x86/x86_ieeefp.h>
	* Deprecated historical FPU control interface
	*
	* IEEE floating point type, constant and function definitions.
	* XXX: FPFLD and FPOFF are undocumented pollution.
	*/

	#ifndef _SYS_CDEFS_H_
	#error this file needs sys/cdefs.h as a prerequisite
	#endif

	/*
	* Rounding modes.
	*/
	typedef enum {
	FP_RN=0, /* round to nearest */
	FP_RM, /* round down towards minus infinity */
	FP_RP, /* round up towards plus infinity */
	FP_RZ /* truncate */
	} fp_rnd_t;

	/*
	* Precision (i.e., rounding precision) modes.
	*/
	typedef enum {
	FP_PS=0, /* 24 bit (single-precision) */
	FP_PRS, /* reserved */
	FP_PD, /* 53 bit (double-precision) */
	FP_PE /* 64 bit (extended-precision) */
	} fp_prec_t;

	#define fp_except_t int

	/*
	* Exception bit masks.
	*/
	#define FP_X_INV 0x01 /* invalid operation */
	#define FP_X_DNML 0x02 /* denormal */
	#define FP_X_DZ 0x04 /* zero divide */
	#define FP_X_OFL 0x08 /* overflow */
	#define FP_X_UFL 0x10 /* underflow */
	#define FP_X_IMP 0x20 /* (im)precision */
	#define FP_X_STK 0x40 /* stack fault */

	/*
	* FPU control word bit-field masks.
	*/
	#define FP_MSKS_FLD 0x3f /* exception masks field */
	#define FP_PRC_FLD 0x300 /* precision control field */
	#define FP_RND_FLD 0xc00 /* rounding control field */

	/*
	* FPU status word bit-field masks.
	*/
	#define FP_STKY_FLD 0x3f /* sticky flags field */

	/*
	* FPU control word bit-field offsets (shift counts).
	*/
	#define FP_MSKS_OFF 0 /* exception masks offset */
	#define FP_PRC_OFF 8 /* precision control offset */
	#define FP_RND_OFF 10 /* rounding control offset */

	/*
	* FPU status word bit-field offsets (shift counts).
	*/
	#define FP_STKY_OFF 0 /* sticky flags offset */

	#ifdef __GNUCLIKE_ASM			#ifdef __GNUCLIKE_ASM

	#define __fldcw(addr) __asm __volatile("fldcw %0" : : "m" (*(addr)))
	#define __fldenv(addr) __asm __volatile("fldenv %0" : : "m" (*(addr)))
	#define __fnclex() __asm __volatile("fnclex")
	#define __fnstcw(addr) __asm __volatile("fnstcw %0" : "=m" (*(addr)))
	#define __fnstenv(addr) __asm __volatile("fnstenv %0" : "=m" (*(addr)))
	#define __fnstsw(addr) __asm __volatile("fnstsw %0" : "=m" (*(addr)))
	#define __ldmxcsr(addr) __asm __volatile("ldmxcsr %0" : : "m" (*(addr)))
	#define __stmxcsr(addr) __asm __volatile("stmxcsr %0" : "=m" (*(addr)))

	/*
	* Load the control word. Be careful not to trap if there is a currently
	* unmasked exception (ones that will become freshly unmasked are not a
	* problem). This case must be handled by a save/restore of the
	* environment or even of the full x87 state. Accessing the environment
	* is very inefficient, so only do it when necessary.
	*/
	static __inline void
	__fnldcw(unsigned short _cw, unsigned short _newcw)
	{
	struct {
	unsigned _cw;
	unsigned _other[6];
	} _env;
	unsigned short _sw;

	if ((_cw & FP_MSKS_FLD) != FP_MSKS_FLD) {
	__fnstsw(&_sw);
	if (((_sw & ~_cw) & FP_STKY_FLD) != 0) {
	__fnstenv(&_env);
	_env._cw = _newcw;
	__fldenv(&_env);
	return;
	}
	}
	__fldcw(&_newcw);
	}

	static __inline fp_rnd_t			static __inline fp_rnd_t
	fpgetround(void)			fpgetround(void)
	{			{
	unsigned short _cw;			unsigned short _cw;

	__fnstcw(&_cw);			__fnstcw(&_cw);
	return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));			return ((fp_rnd_t)((_cw & FP_RND_FLD) >> FP_RND_OFF));
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