xref: /freebsd/sys/amd64/include/fpu.h (revision a35d88931c87cfe6bd38f01d7bad22140b3b38f3)
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 /*
77  * The hardware default control word for i387's and later coprocessors is
78  * 0x37F, giving:
79  *
80  *	round to nearest
81  *	64-bit precision
82  *	all exceptions masked.
83  *
84  * FreeBSD/i386 uses 53 bit precision for things like fadd/fsub/fsqrt etc
85  * because of the difference between memory and fpu register stack arguments.
86  * If its using an intermediate fpu register, it has 80/64 bits to work
87  * with.  If it uses memory, it has 64/53 bits to work with.  However,
88  * gcc is aware of this and goes to a fair bit of trouble to make the
89  * best use of it.
90  *
91  * This is mostly academic for AMD64, because the ABI prefers the use
92  * SSE2 based math.  For FreeBSD/amd64, we go with the default settings.
93  */
94 #define	__INITIAL_FPUCW__	0x037F
95 #define	__INITIAL_MXCSR__	0x1F80
96 #define	__INITIAL_MXCSR_MASK__	0xFFBF
97 
98 #ifdef _KERNEL
99 int	fpudna(void);
100 void	fpudrop(void);
101 void	fpuexit(struct thread *td);
102 int	fpuformat(void);
103 int	fpugetregs(struct thread *td, struct savefpu *addr);
104 void	fpuinit(void);
105 void	fpusetregs(struct thread *td, struct savefpu *addr);
106 int	fputrap(void);
107 #endif
108 
109 #endif /* !_MACHINE_FPU_H_ */
110