1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*---------------------------------------------------------------------------+
3 | fpu_emu.h |
4 | |
5 | Copyright (C) 1992,1993,1994,1997 |
6 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
7 | Australia. E-mail billm@suburbia.net |
8 | |
9 +---------------------------------------------------------------------------*/
10
11 #ifndef _FPU_EMU_H_
12 #define _FPU_EMU_H_
13
14 /*
15 * Define PECULIAR_486 to get a closer approximation to 80486 behaviour,
16 * rather than behaviour which appears to be cleaner.
17 * This is a matter of opinion: for all I know, the 80486 may simply
18 * be complying with the IEEE spec. Maybe one day I'll get to see the
19 * spec...
20 */
21 #define PECULIAR_486
22
23 #ifdef __ASSEMBLY__
24 #include "fpu_asm.h"
25 #define Const(x) $##x
26 #else
27 #define Const(x) x
28 #endif
29
30 #define EXP_BIAS Const(0)
31 #define EXP_OVER Const(0x4000) /* smallest invalid large exponent */
32 #define EXP_UNDER Const(-0x3fff) /* largest invalid small exponent */
33 #define EXP_WAY_UNDER Const(-0x6000) /* Below the smallest denormal, but
34 still a 16 bit nr. */
35 #define EXP_Infinity EXP_OVER
36 #define EXP_NaN EXP_OVER
37
38 #define EXTENDED_Ebias Const(0x3fff)
39 #define EXTENDED_Emin (-0x3ffe) /* smallest valid exponent */
40
41 #define SIGN_POS Const(0)
42 #define SIGN_NEG Const(0x80)
43
44 #define SIGN_Positive Const(0)
45 #define SIGN_Negative Const(0x8000)
46
47 /* Keep the order TAG_Valid, TAG_Zero, TW_Denormal */
48 /* The following fold to 2 (Special) in the Tag Word */
49 #define TW_Denormal Const(4) /* De-normal */
50 #define TW_Infinity Const(5) /* + or - infinity */
51 #define TW_NaN Const(6) /* Not a Number */
52 #define TW_Unsupported Const(7) /* Not supported by an 80486 */
53
54 #define TAG_Valid Const(0) /* valid */
55 #define TAG_Zero Const(1) /* zero */
56 #define TAG_Special Const(2) /* De-normal, + or - infinity,
57 or Not a Number */
58 #define TAG_Empty Const(3) /* empty */
59 #define TAG_Error Const(0x80) /* probably need to abort */
60
61 #define LOADED_DATA Const(10101) /* Special st() number to identify
62 loaded data (not on stack). */
63
64 /* A few flags (must be >= 0x10). */
65 #define REV 0x10
66 #define DEST_RM 0x20
67 #define LOADED 0x40
68
69 #define FPU_Exception Const(0x80000000) /* Added to tag returns. */
70
71 #ifndef __ASSEMBLY__
72
73 #include "fpu_system.h"
74
75 #include <uapi/asm/sigcontext.h> /* for struct _fpstate */
76 #include <asm/math_emu.h>
77 #include <linux/linkage.h>
78
79 /*
80 #define RE_ENTRANT_CHECKING
81 */
82
83 #ifdef RE_ENTRANT_CHECKING
84 extern u_char emulating;
85 # define RE_ENTRANT_CHECK_OFF emulating = 0
86 # define RE_ENTRANT_CHECK_ON emulating = 1
87 #else
88 # define RE_ENTRANT_CHECK_OFF
89 # define RE_ENTRANT_CHECK_ON
90 #endif /* RE_ENTRANT_CHECKING */
91
92 #define FWAIT_OPCODE 0x9b
93 #define OP_SIZE_PREFIX 0x66
94 #define ADDR_SIZE_PREFIX 0x67
95 #define PREFIX_CS 0x2e
96 #define PREFIX_DS 0x3e
97 #define PREFIX_ES 0x26
98 #define PREFIX_SS 0x36
99 #define PREFIX_FS 0x64
100 #define PREFIX_GS 0x65
101 #define PREFIX_REPE 0xf3
102 #define PREFIX_REPNE 0xf2
103 #define PREFIX_LOCK 0xf0
104 #define PREFIX_CS_ 1
105 #define PREFIX_DS_ 2
106 #define PREFIX_ES_ 3
107 #define PREFIX_FS_ 4
108 #define PREFIX_GS_ 5
109 #define PREFIX_SS_ 6
110 #define PREFIX_DEFAULT 7
111
112 struct address {
113 unsigned int offset;
114 unsigned int selector:16;
115 unsigned int opcode:11;
116 unsigned int empty:5;
117 };
118 struct fpu__reg {
119 unsigned sigl;
120 unsigned sigh;
121 short exp;
122 };
123
124 typedef void (*FUNC) (void);
125 typedef struct fpu__reg FPU_REG;
126 typedef void (*FUNC_ST0) (FPU_REG *st0_ptr, u_char st0_tag);
127 typedef struct {
128 u_char address_size, operand_size, segment;
129 } overrides;
130 /* This structure is 32 bits: */
131 typedef struct {
132 overrides override;
133 u_char default_mode;
134 } fpu_addr_modes;
135 /* PROTECTED has a restricted meaning in the emulator; it is used
136 to signal that the emulator needs to do special things to ensure
137 that protection is respected in a segmented model. */
138 #define PROTECTED 4
139 #define SIXTEEN 1 /* We rely upon this being 1 (true) */
140 #define VM86 SIXTEEN
141 #define PM16 (SIXTEEN | PROTECTED)
142 #define SEG32 PROTECTED
143 extern u_char const data_sizes_16[32];
144
145 #define register_base ((u_char *) registers )
146 #define fpu_register(x) ( * ((FPU_REG *)( register_base + 10 * (x & 7) )) )
147 #define st(x) ( * ((FPU_REG *)( register_base + 10 * ((top+x) & 7) )) )
148
149 #define STACK_OVERFLOW (FPU_stackoverflow(&st_new_ptr))
150 #define NOT_EMPTY(i) (!FPU_empty_i(i))
151
152 #define NOT_EMPTY_ST0 (st0_tag ^ TAG_Empty)
153
154 #define poppop() { FPU_pop(); FPU_pop(); }
155
156 /* push() does not affect the tags */
157 #define push() { top--; }
158
159 #define signbyte(a) (((u_char *)(a))[9])
160 #define getsign(a) (signbyte(a) & 0x80)
161 #define setsign(a,b) { if ((b) != 0) signbyte(a) |= 0x80; else signbyte(a) &= 0x7f; }
162 #define copysign(a,b) { if (getsign(a)) signbyte(b) |= 0x80; \
163 else signbyte(b) &= 0x7f; }
164 #define changesign(a) { signbyte(a) ^= 0x80; }
165 #define setpositive(a) { signbyte(a) &= 0x7f; }
166 #define setnegative(a) { signbyte(a) |= 0x80; }
167 #define signpositive(a) ( (signbyte(a) & 0x80) == 0 )
168 #define signnegative(a) (signbyte(a) & 0x80)
169
170 static inline void reg_copy(FPU_REG const *x, FPU_REG *y)
171 {
172 *(short *)&(y->exp) = *(const short *)&(x->exp);
173 *(long long *)&(y->sigl) = *(const long long *)&(x->sigl);
174 }
175
176 #define exponent(x) (((*(short *)&((x)->exp)) & 0x7fff) - EXTENDED_Ebias)
177 #define setexponentpos(x,y) { (*(short *)&((x)->exp)) = \
178 ((y) + EXTENDED_Ebias) & 0x7fff; }
179 #define exponent16(x) (*(short *)&((x)->exp))
180 #define setexponent16(x,y) { (*(short *)&((x)->exp)) = (u16)(y); }
181 #define addexponent(x,y) { (*(short *)&((x)->exp)) += (y); }
182 #define stdexp(x) { (*(short *)&((x)->exp)) += EXTENDED_Ebias; }
183
184 #define isdenormal(ptr) (exponent(ptr) == EXP_BIAS+EXP_UNDER)
185
186 #define significand(x) ( ((unsigned long long *)&((x)->sigl))[0] )
187
188 /*----- Prototypes for functions written in assembler -----*/
189 /* extern void reg_move(FPU_REG *a, FPU_REG *b); */
190
191 asmlinkage int FPU_normalize(FPU_REG *x);
192 asmlinkage int FPU_normalize_nuo(FPU_REG *x);
193 asmlinkage int FPU_u_sub(FPU_REG const *arg1, FPU_REG const *arg2,
194 FPU_REG * answ, unsigned int control_w, u_char sign,
195 int expa, int expb);
196 asmlinkage int FPU_u_mul(FPU_REG const *arg1, FPU_REG const *arg2,
197 FPU_REG * answ, unsigned int control_w, u_char sign,
198 int expon);
199 asmlinkage int FPU_u_div(FPU_REG const *arg1, FPU_REG const *arg2,
200 FPU_REG * answ, unsigned int control_w, u_char sign);
201 asmlinkage int FPU_u_add(FPU_REG const *arg1, FPU_REG const *arg2,
202 FPU_REG * answ, unsigned int control_w, u_char sign,
203 int expa, int expb);
204 asmlinkage int wm_sqrt(FPU_REG *n, int dummy1, int dummy2,
205 unsigned int control_w, u_char sign);
206 asmlinkage unsigned FPU_shrx(void *l, unsigned x);
207 asmlinkage unsigned FPU_shrxs(void *v, unsigned x);
208 asmlinkage unsigned long FPU_div_small(unsigned long long *x, unsigned long y);
209 asmlinkage int FPU_round(FPU_REG *arg, unsigned int extent, int dummy,
210 unsigned int control_w, u_char sign);
211
212 #ifndef MAKING_PROTO
213 #include "fpu_proto.h"
214 #endif
215
216 #endif /* __ASSEMBLY__ */
217
218 #endif /* _FPU_EMU_H_ */
219
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