Move a private x86-64 header file out of the limelight.

Currently this is on everyone's include path and is getting exported
via the NDK.

Change-Id: Ia417839fb65c7e0afddcd9fae3438665dae8e752

libm/include/amd64/machine/fpu.h

@@ -0,0 +1,65 @@
+/*	$OpenBSD: fpu.h,v 1.9 2011/03/23 16:54:34 pirofti Exp $	*/
+/*	$NetBSD: fpu.h,v 1.1 2003/04/26 18:39:40 fvdl Exp $	*/
+
+#ifndef	_MACHINE_FPU_H_
+#define	_MACHINE_FPU_H_
+
+#include <sys/types.h>
+
+/*
+ * 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.
+ * Must be stored in memory on a 16-byte boundary.
+ */
+
+struct fxsave64 {
+	u_int16_t  fx_fcw;
+	u_int16_t  fx_fsw;
+	u_int8_t   fx_ftw;
+	u_int8_t   fx_unused1;
+	u_int16_t  fx_fop;
+	u_int64_t  fx_rip;
+	u_int64_t  fx_rdp;
+	u_int32_t  fx_mxcsr;
+	u_int32_t  fx_mxcsr_mask;
+	u_int64_t  fx_st[8][2];   /* 8 normal FP regs */
+	u_int64_t  fx_xmm[16][2]; /* 16 SSE2 registers */
+	u_int8_t   fx_unused3[96];
+} __packed;
+
+struct savefpu {
+	struct fxsave64 fp_fxsave;	/* see above */
+	u_int16_t fp_ex_sw;		/* saved status from last exception */
+	u_int16_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
+
+#ifdef _KERNEL
+/*
+ * XXX
+ */
+struct trapframe;
+struct cpu_info;
+
+extern uint32_t	fpu_mxcsr_mask;
+
+void fpuinit(struct cpu_info *);
+void fpudrop(void);
+void fpudiscard(struct proc *);
+void fputrap(struct trapframe *);
+void fpusave_proc(struct proc *, int);
+void fpusave_cpu(struct cpu_info *, int);
+void fpu_kernel_enter(void);
+void fpu_kernel_exit(void);
+
+#endif
+
+#endif /* _MACHINE_FPU_H_ */