2014-01-15 10:53:42 +01:00

92 lines
2.7 KiB
C

/* $NetBSD: fpu.h,v 1.10 2013/12/01 01:05:16 christos Exp $ */
#ifndef _AMD64_FPU_H_
#define _AMD64_FPU_H_
/*
* NetBSD/amd64 only uses the extended save/restore format used
* by fxsave/fsrestore, to always deal with the SSE registers,
* which are part of the ABI to pass floating point values.
*
* The memory used for the 'fsave' instruction must be 16 byte aligned,
* but the definition here isn't aligned to avoid padding elsewhere.
*/
struct fxsave64 {
uint16_t fx_fcw; /* 0: FPU control word */
uint16_t fx_fsw; /* 2: FPU status word */
uint8_t fx_ftw; /* 4: Abridged FPU tag word */
uint8_t fx_reserved1; /* 5: */
uint16_t fx_fop; /* 6: Low 11 bits are FPU opcode */
uint64_t fx_rip; /* 8: Address of faulting instruction */
uint64_t fx_rdp; /* 16: Data address associated with fault */
uint32_t fx_mxcsr; /* 24: SIMD control & status */
uint32_t fx_mxcsr_mask; /* 28: */
uint64_t fx_st[8][2]; /* 32: 8 normal FP regs (80 bit) */
uint64_t fx_xmm[16][2]; /* 160: 16 SSE2 registers */
uint8_t fx_reserved2[48]; /* 416: */
uint8_t fx_available[48]; /* 464: could be used by kernel */
};
__CTASSERT(sizeof (struct fxsave64) == 512);
struct savefpu {
struct fxsave64 fp_fxsave; /* see above */
};
struct savefpu_i387 {
uint16_t fp_ex_sw; /* saved status from last exception */
uint16_t fp_ex_tw; /* saved tag from last exception */
};
/*
* The i387 defaults to Intel extended precision mode and round to nearest,
* with all exceptions masked.
*/
#define __INITIAL_NPXCW__ 0x037f
#define __INITIAL_MXCSR__ 0x1f80
#define __INITIAL_MXCSR_MASK__ 0xffbf
/* Modern NetBSD uses the default control word.. */
#define __NetBSD_NPXCW__ 0x037f
/* NetBSD before 6.99.26 forced IEEE double precision. */
#define __NetBSD_COMPAT_NPXCW__ 0x127f
/* Linux just uses the default control word. */
#define __Linux_NPXCW__ 0x037f
/*
* The standard control word from finit is 0x37F, giving:
* round to nearest
* 64-bit precision
* all exceptions masked.
*
* Now we want:
* affine mode (if we decide to support 287's)
* round to nearest
* 53-bit precision
* all exceptions masked.
*
* 64-bit precision often gives bad results with high level languages
* because it makes the results of calculations depend on whether
* intermediate values are stored in memory or in FPU registers.
*/
#ifdef _KERNEL
/*
* XXX
*/
struct trapframe;
struct cpu_info;
void fpuinit(struct cpu_info *);
void fpudrop(void);
void fpusave(struct lwp *);
void fpudiscard(struct lwp *);
void fputrap(struct trapframe *);
void fpusave_lwp(struct lwp *, bool);
void fpusave_cpu(bool);
#endif
#endif /* _AMD64_FPU_H_ */