xref: /freebsd/sys/amd64/include/fpu.h (revision bb15ca603fa442c72dde3f3cb8b46db6970e3950)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * William Jolitz.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  *
32  *	from: @(#)npx.h	5.3 (Berkeley) 1/18/91
33  * $FreeBSD$
34  */
35 
36 /*
37  * Floating Point Data Structures and Constants
38  * W. Jolitz 1/90
39  */
40 
41 #ifndef _MACHINE_FPU_H_
42 #define	_MACHINE_FPU_H_
43 
44 /* Contents of each x87 floating point accumulator */
45 struct fpacc87 {
46 	u_char	fp_bytes[10];
47 };
48 
49 /* Contents of each SSE extended accumulator */
50 struct  xmmacc {
51 	u_char	xmm_bytes[16];
52 };
53 
54 struct  envxmm {
55 	u_int16_t	en_cw;		/* control word (16bits) */
56 	u_int16_t	en_sw;		/* status word (16bits) */
57 	u_int8_t	en_tw;		/* tag word (8bits) */
58 	u_int8_t	en_zero;
59 	u_int16_t	en_opcode;	/* opcode last executed (11 bits ) */
60 	u_int64_t	en_rip;		/* floating point instruction pointer */
61 	u_int64_t	en_rdp;		/* floating operand pointer */
62 	u_int32_t	en_mxcsr;	/* SSE sontorol/status register */
63 	u_int32_t	en_mxcsr_mask;	/* valid bits in mxcsr */
64 };
65 
66 struct  savefpu {
67 	struct	envxmm	sv_env;
68 	struct {
69 		struct fpacc87	fp_acc;
70 		u_char		fp_pad[6];      /* padding */
71 	} sv_fp[8];
72 	struct xmmacc	sv_xmm[16];
73 	u_char sv_pad[96];
74 } __aligned(16);
75 
76 #ifdef _KERNEL
77 struct fpu_kern_ctx {
78 	struct savefpu hwstate;
79 	struct savefpu *prev;
80 	uint32_t flags;
81 };
82 #define	FPU_KERN_CTX_FPUINITDONE 0x01
83 
84 #define	PCB_USER_FPU(pcb) (((pcb)->pcb_flags & PCB_KERNFPU) == 0)
85 #endif
86 
87 /*
88  * The hardware default control word for i387's and later coprocessors is
89  * 0x37F, giving:
90  *
91  *	round to nearest
92  *	64-bit precision
93  *	all exceptions masked.
94  *
95  * FreeBSD/i386 uses 53 bit precision for things like fadd/fsub/fsqrt etc
96  * because of the difference between memory and fpu register stack arguments.
97  * If its using an intermediate fpu register, it has 80/64 bits to work
98  * with.  If it uses memory, it has 64/53 bits to work with.  However,
99  * gcc is aware of this and goes to a fair bit of trouble to make the
100  * best use of it.
101  *
102  * This is mostly academic for AMD64, because the ABI prefers the use
103  * SSE2 based math.  For FreeBSD/amd64, we go with the default settings.
104  */
105 #define	__INITIAL_FPUCW__	0x037F
106 #define	__INITIAL_FPUCW_I386__	0x127F
107 #define	__INITIAL_MXCSR__	0x1F80
108 #define	__INITIAL_MXCSR_MASK__	0xFFBF
109 
110 #ifdef _KERNEL
111 void	fpudna(void);
112 void	fpudrop(void);
113 void	fpuexit(struct thread *td);
114 int	fpuformat(void);
115 int	fpugetregs(struct thread *td);
116 void	fpuinit(void);
117 void	fpusetregs(struct thread *td, struct savefpu *addr);
118 int	fputrap(void);
119 void	fpuuserinited(struct thread *td);
120 int	fpu_kern_enter(struct thread *td, struct fpu_kern_ctx *ctx,
121 	    u_int flags);
122 int	fpu_kern_leave(struct thread *td, struct fpu_kern_ctx *ctx);
123 int	fpu_kern_thread(u_int flags);
124 int	is_fpu_kern_thread(u_int flags);
125 
126 /*
127  * Flags for fpu_kern_enter() and fpu_kern_thread().
128  */
129 #define	FPU_KERN_NORMAL	0x0000
130 
131 #endif
132 
133 #endif /* !_MACHINE_FPU_H_ */
134