xref: /freebsd/sys/x86/include/fpu.h (revision eda14cbc264d6969b02f2b1994cef11148e914f1)
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  * 3. 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 _X86_FPU_H_
42 #define	_X86_FPU_H_
43 
44 /* Environment information of floating point unit. */
45 struct env87 {
46 	int32_t		en_cw;		/* control word (16bits) */
47 	int32_t		en_sw;		/* status word (16bits) */
48 	int32_t		en_tw;		/* tag word (16bits) */
49 	int32_t		en_fip;		/* fp instruction pointer */
50 	uint16_t	en_fcs;		/* fp code segment selector */
51 	uint16_t	en_opcode;	/* opcode last executed (11 bits) */
52 	int32_t		en_foo;		/* fp operand offset */
53 	int32_t		en_fos;		/* fp operand segment selector */
54 };
55 
56 /* Contents of each x87 floating point accumulator. */
57 struct fpacc87 {
58 	uint8_t		fp_bytes[10];
59 };
60 
61 /* Floating point context. (i386 fnsave/frstor) */
62 struct save87 {
63 	struct env87	sv_env;		/* floating point control/status */
64 	struct fpacc87	sv_ac[8];	/* accumulator contents, 0-7 */
65 	uint8_t		sv_pad0[4];	/* saved status word (now unused) */
66 	uint8_t		sv_pad[64];
67 };
68 
69 /* Contents of each SSE extended accumulator. */
70 struct xmmacc {
71 	uint8_t		xmm_bytes[16];
72 };
73 
74 /* Contents of the upper 16 bytes of each AVX extended accumulator. */
75 struct ymmacc {
76 	uint8_t		ymm_bytes[16];
77 };
78 
79 /* Rename structs below depending on machine architecture. */
80 #ifdef __i386__
81 #define	__envxmm32	envxmm
82 #else
83 #define	__envxmm32	envxmm32
84 #define	__envxmm64	envxmm
85 #endif
86 
87 struct __envxmm32 {
88 	uint16_t	en_cw;		/* control word (16bits) */
89 	uint16_t	en_sw;		/* status word (16bits) */
90 	uint16_t	en_tw;		/* tag word (16bits) */
91 	uint16_t	en_opcode;	/* opcode last executed (11 bits) */
92 	uint32_t	en_fip;		/* fp instruction pointer */
93 	uint16_t	en_fcs;		/* fp code segment selector */
94 	uint16_t	en_pad0;	/* padding */
95 	uint32_t	en_foo;		/* fp operand offset */
96 	uint16_t	en_fos;		/* fp operand segment selector */
97 	uint16_t	en_pad1;	/* padding */
98 	uint32_t	en_mxcsr;	/* SSE control/status register */
99 	uint32_t	en_mxcsr_mask;	/* valid bits in mxcsr */
100 };
101 
102 struct __envxmm64 {
103 	uint16_t	en_cw;		/* control word (16bits) */
104 	uint16_t	en_sw;		/* status word (16bits) */
105 	uint8_t		en_tw;		/* tag word (8bits) */
106 	uint8_t		en_zero;
107 	uint16_t	en_opcode;	/* opcode last executed (11 bits ) */
108 	uint64_t	en_rip;		/* fp instruction pointer */
109 	uint64_t	en_rdp;		/* fp operand pointer */
110 	uint32_t	en_mxcsr;	/* SSE control/status register */
111 	uint32_t	en_mxcsr_mask;	/* valid bits in mxcsr */
112 };
113 
114 /* Floating point context. (i386 fxsave/fxrstor) */
115 struct savexmm {
116 	struct __envxmm32	sv_env;
117 	struct {
118 		struct fpacc87	fp_acc;
119 		uint8_t		fp_pad[6];      /* padding */
120 	} sv_fp[8];
121 	struct xmmacc		sv_xmm[8];
122 	uint8_t			sv_pad[224];
123 } __aligned(16);
124 
125 #ifdef __i386__
126 union savefpu {
127 	struct save87	sv_87;
128 	struct savexmm	sv_xmm;
129 };
130 #else
131 /* Floating point context. (amd64 fxsave/fxrstor) */
132 struct savefpu {
133 	struct __envxmm64	sv_env;
134 	struct {
135 		struct fpacc87	fp_acc;
136 		uint8_t		fp_pad[6];	/* padding */
137 	} sv_fp[8];
138 	struct xmmacc		sv_xmm[16];
139 	uint8_t			sv_pad[96];
140 } __aligned(16);
141 #endif
142 
143 struct xstate_hdr {
144 	uint64_t	xstate_bv;
145 	uint64_t	xstate_xcomp_bv;
146 	uint8_t		xstate_rsrv0[8];
147 	uint8_t		xstate_rsrv[40];
148 };
149 #define	XSTATE_XCOMP_BV_COMPACT	(1ULL << 63)
150 
151 struct savexmm_xstate {
152 	struct xstate_hdr	sx_hd;
153 	struct ymmacc		sx_ymm[16];
154 };
155 
156 struct savexmm_ymm {
157 	struct __envxmm32	sv_env;
158 	struct {
159 		struct fpacc87	fp_acc;
160 		int8_t		fp_pad[6];	/* padding */
161 	} sv_fp[8];
162 	struct xmmacc		sv_xmm[16];
163 	uint8_t			sv_pad[96];
164 	struct savexmm_xstate	sv_xstate;
165 } __aligned(64);
166 
167 struct savefpu_xstate {
168 	struct xstate_hdr	sx_hd;
169 	struct ymmacc		sx_ymm[16];
170 };
171 
172 struct savefpu_ymm {
173 	struct __envxmm64	sv_env;
174 	struct {
175 		struct fpacc87	fp_acc;
176 		int8_t		fp_pad[6];	/* padding */
177 	} sv_fp[8];
178 	struct xmmacc		sv_xmm[16];
179 	uint8_t			sv_pad[96];
180 	struct savefpu_xstate	sv_xstate;
181 } __aligned(64);
182 
183 #undef __envxmm32
184 #undef __envxmm64
185 
186 /*
187  * The hardware default control word for i387's and later coprocessors is
188  * 0x37F, giving:
189  *
190  *	round to nearest
191  *	64-bit precision
192  *	all exceptions masked.
193  *
194  * FreeBSD/i386 uses 53 bit precision for things like fadd/fsub/fsqrt etc
195  * because of the difference between memory and fpu register stack arguments.
196  * If its using an intermediate fpu register, it has 80/64 bits to work
197  * with.  If it uses memory, it has 64/53 bits to work with.  However,
198  * gcc is aware of this and goes to a fair bit of trouble to make the
199  * best use of it.
200  *
201  * This is mostly academic for AMD64, because the ABI prefers the use
202  * SSE2 based math.  For FreeBSD/amd64, we go with the default settings.
203  */
204 #define	__INITIAL_FPUCW__	0x037F
205 #define	__INITIAL_FPUCW_I386__	0x127F
206 #define	__INITIAL_NPXCW__	__INITIAL_FPUCW_I386__
207 #define	__INITIAL_MXCSR__	0x1F80
208 #define	__INITIAL_MXCSR_MASK__	0xFFBF
209 
210 /*
211  * The current value of %xcr0 is saved in the sv_pad[] field of the FPU
212  * state in the NT_X86_XSTATE note in core dumps.  This offset is chosen
213  * to match the offset used by NT_X86_XSTATE in other systems.
214  */
215 #define	X86_XSTATE_XCR0_OFFSET	464
216 
217 #endif /* !_X86_FPU_H_ */
218