Differential D26292 Diff 76575 sys/x86/include/x86_ieeefp.h

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sys/x86/include/x86_ieeefp.h

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				/*
				* Deprecated historical FPU control interface
				*
				* IEEE floating point type, constant and function definitions.
				* XXX: {FP,SSE}FLD and {FP,SSE}OFF 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

				#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);
				}

				#endif /* __GNUCLIKE_ASM */