xref: /freebsd/sys/x86/include/fpu.h (revision edf8578117e8844e02c0121147f45e4609b30680)
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  */
34 
35 /*
36  * Floating Point Data Structures and Constants
37  * W. Jolitz 1/90
38  */
39 
40 #ifndef _X86_FPU_H_
41 #define	_X86_FPU_H_
42 
43 /* Environment information of floating point unit. */
44 struct env87 {
45 	int32_t		en_cw;		/* control word (16bits) */
46 	int32_t		en_sw;		/* status word (16bits) */
47 	int32_t		en_tw;		/* tag word (16bits) */
48 	int32_t		en_fip;		/* fp instruction pointer */
49 	uint16_t	en_fcs;		/* fp code segment selector */
50 	uint16_t	en_opcode;	/* opcode last executed (11 bits) */
51 	int32_t		en_foo;		/* fp operand offset */
52 	int32_t		en_fos;		/* fp operand segment selector */
53 };
54 
55 /* Contents of each x87 floating point accumulator. */
56 struct fpacc87 {
57 	uint8_t		fp_bytes[10];
58 };
59 
60 /* Floating point context. (i386 fnsave/frstor) */
61 struct save87 {
62 	struct env87	sv_env;		/* floating point control/status */
63 	struct fpacc87	sv_ac[8];	/* accumulator contents, 0-7 */
64 	uint8_t		sv_pad0[4];	/* saved status word (now unused) */
65 	uint8_t		sv_pad[64];
66 };
67 
68 /* Contents of each SSE extended accumulator. */
69 struct xmmacc {
70 	uint8_t		xmm_bytes[16];
71 };
72 
73 /* Contents of the upper 16 bytes of each AVX extended accumulator. */
74 struct ymmacc {
75 	uint8_t		ymm_bytes[16];
76 };
77 
78 /* Rename structs below depending on machine architecture. */
79 #ifdef __i386__
80 #define	__envxmm32	envxmm
81 #else
82 #define	__envxmm32	envxmm32
83 #define	__envxmm64	envxmm
84 #endif
85 
86 struct __envxmm32 {
87 	uint16_t	en_cw;		/* control word (16bits) */
88 	uint16_t	en_sw;		/* status word (16bits) */
89 	uint16_t	en_tw;		/* tag word (16bits) */
90 	uint16_t	en_opcode;	/* opcode last executed (11 bits) */
91 	uint32_t	en_fip;		/* fp instruction pointer */
92 	uint16_t	en_fcs;		/* fp code segment selector */
93 	uint16_t	en_pad0;	/* padding */
94 	uint32_t	en_foo;		/* fp operand offset */
95 	uint16_t	en_fos;		/* fp operand segment selector */
96 	uint16_t	en_pad1;	/* padding */
97 	uint32_t	en_mxcsr;	/* SSE control/status register */
98 	uint32_t	en_mxcsr_mask;	/* valid bits in mxcsr */
99 };
100 
101 struct __envxmm64 {
102 	uint16_t	en_cw;		/* control word (16bits) */
103 	uint16_t	en_sw;		/* status word (16bits) */
104 	uint8_t		en_tw;		/* tag word (8bits) */
105 	uint8_t		en_zero;
106 	uint16_t	en_opcode;	/* opcode last executed (11 bits ) */
107 	uint64_t	en_rip;		/* fp instruction pointer */
108 	uint64_t	en_rdp;		/* fp operand pointer */
109 	uint32_t	en_mxcsr;	/* SSE control/status register */
110 	uint32_t	en_mxcsr_mask;	/* valid bits in mxcsr */
111 };
112 
113 /* Floating point context. (i386 fxsave/fxrstor) */
114 struct savexmm {
115 	struct __envxmm32	sv_env;
116 	struct {
117 		struct fpacc87	fp_acc;
118 		uint8_t		fp_pad[6];      /* padding */
119 	} sv_fp[8];
120 	struct xmmacc		sv_xmm[8];
121 	uint8_t			sv_pad[224];
122 } __aligned(16);
123 
124 #ifdef __i386__
125 union savefpu {
126 	struct save87	sv_87;
127 	struct savexmm	sv_xmm;
128 };
129 #else
130 /* Floating point context. (amd64 fxsave/fxrstor) */
131 struct savefpu {
132 	struct __envxmm64	sv_env;
133 	struct {
134 		struct fpacc87	fp_acc;
135 		uint8_t		fp_pad[6];	/* padding */
136 	} sv_fp[8];
137 	struct xmmacc		sv_xmm[16];
138 	uint8_t			sv_pad[96];
139 } __aligned(16);
140 #endif
141 
142 struct xstate_hdr {
143 	uint64_t	xstate_bv;
144 	uint64_t	xstate_xcomp_bv;
145 	uint8_t		xstate_rsrv0[8];
146 	uint8_t		xstate_rsrv[40];
147 };
148 #define	XSTATE_XCOMP_BV_COMPACT	(1ULL << 63)
149 
150 struct savexmm_xstate {
151 	struct xstate_hdr	sx_hd;
152 	struct ymmacc		sx_ymm[16];
153 };
154 
155 struct savexmm_ymm {
156 	struct __envxmm32	sv_env;
157 	struct {
158 		struct fpacc87	fp_acc;
159 		int8_t		fp_pad[6];	/* padding */
160 	} sv_fp[8];
161 	struct xmmacc		sv_xmm[16];
162 	uint8_t			sv_pad[96];
163 	struct savexmm_xstate	sv_xstate;
164 } __aligned(64);
165 
166 struct savefpu_xstate {
167 	struct xstate_hdr	sx_hd;
168 	struct ymmacc		sx_ymm[16];
169 };
170 
171 struct savefpu_ymm {
172 	struct __envxmm64	sv_env;
173 	struct {
174 		struct fpacc87	fp_acc;
175 		int8_t		fp_pad[6];	/* padding */
176 	} sv_fp[8];
177 	struct xmmacc		sv_xmm[16];
178 	uint8_t			sv_pad[96];
179 	struct savefpu_xstate	sv_xstate;
180 } __aligned(64);
181 
182 #undef __envxmm32
183 #undef __envxmm64
184 
185 /*
186  * The hardware default control word for i387's and later coprocessors is
187  * 0x37F, giving:
188  *
189  *	round to nearest
190  *	64-bit precision
191  *	all exceptions masked.
192  *
193  * FreeBSD/i386 uses 53 bit precision for things like fadd/fsub/fsqrt etc
194  * because of the difference between memory and fpu register stack arguments.
195  * If its using an intermediate fpu register, it has 80/64 bits to work
196  * with.  If it uses memory, it has 64/53 bits to work with.  However,
197  * gcc is aware of this and goes to a fair bit of trouble to make the
198  * best use of it.
199  *
200  * This is mostly academic for AMD64, because the ABI prefers the use
201  * SSE2 based math.  For FreeBSD/amd64, we go with the default settings.
202  */
203 #define	__INITIAL_FPUCW__	0x037F
204 #define	__INITIAL_FPUCW_I386__	0x127F
205 #define	__INITIAL_NPXCW__	__INITIAL_FPUCW_I386__
206 #define	__INITIAL_MXCSR__	0x1F80
207 #define	__INITIAL_MXCSR_MASK__	0xFFBF
208 
209 /*
210  * The current value of %xcr0 is saved in the sv_pad[] field of the FPU
211  * state in the NT_X86_XSTATE note in core dumps.  This offset is chosen
212  * to match the offset used by NT_X86_XSTATE in other systems.
213  */
214 #define	X86_XSTATE_XCR0_OFFSET	464
215 
216 #endif /* !_X86_FPU_H_ */
217