File: /usr/src/linux/arch/i386/math-emu/fpu_emu.h
1 /*---------------------------------------------------------------------------+
2 | fpu_emu.h |
3 | |
4 | Copyright (C) 1992,1993,1994,1997 |
5 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
6 | Australia. E-mail billm@suburbia.net |
7 | |
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
48 /* Keep the order TAG_Valid, TAG_Zero, TW_Denormal */
49 /* The following fold to 2 (Special) in the Tag Word */
50 #define TW_Denormal Const(4) /* De-normal */
51 #define TW_Infinity Const(5) /* + or - infinity */
52 #define TW_NaN Const(6) /* Not a Number */
53 #define TW_Unsupported Const(7) /* Not supported by an 80486 */
54
55 #define TAG_Valid Const(0) /* valid */
56 #define TAG_Zero Const(1) /* zero */
57 #define TAG_Special Const(2) /* De-normal, + or - infinity,
58 or Not a Number */
59 #define TAG_Empty Const(3) /* empty */
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
72 #ifndef __ASSEMBLY__
73
74 #include "fpu_system.h"
75
76 #include <asm/sigcontext.h> /* for struct _fpstate */
77 #include <asm/math_emu.h>
78 #include <linux/linkage.h>
79
80 /*
81 #define RE_ENTRANT_CHECKING
82 */
83
84 #ifdef RE_ENTRANT_CHECKING
85 extern u_char emulating;
86 # define RE_ENTRANT_CHECK_OFF emulating = 0
87 # define RE_ENTRANT_CHECK_ON emulating = 1
88 #else
89 # define RE_ENTRANT_CHECK_OFF
90 # define RE_ENTRANT_CHECK_ON
91 #endif /* RE_ENTRANT_CHECKING */
92
93 #define FWAIT_OPCODE 0x9b
94 #define OP_SIZE_PREFIX 0x66
95 #define ADDR_SIZE_PREFIX 0x67
96 #define PREFIX_CS 0x2e
97 #define PREFIX_DS 0x3e
98 #define PREFIX_ES 0x26
99 #define PREFIX_SS 0x36
100 #define PREFIX_FS 0x64
101 #define PREFIX_GS 0x65
102 #define PREFIX_REPE 0xf3
103 #define PREFIX_REPNE 0xf2
104 #define PREFIX_LOCK 0xf0
105 #define PREFIX_CS_ 1
106 #define PREFIX_DS_ 2
107 #define PREFIX_ES_ 3
108 #define PREFIX_FS_ 4
109 #define PREFIX_GS_ 5
110 #define PREFIX_SS_ 6
111 #define PREFIX_DEFAULT 7
112
113 struct address {
114 unsigned int offset;
115 unsigned int selector:16;
116 unsigned int opcode:11;
117 unsigned int empty:5;
118 };
119 struct fpu__reg {
120 unsigned sigl;
121 unsigned sigh;
122 short exp;
123 };
124
125 typedef void (*FUNC)(void);
126 typedef struct fpu__reg FPU_REG;
127 typedef void (*FUNC_ST0)(FPU_REG *st0_ptr, u_char st0_tag);
128 typedef struct { u_char address_size, operand_size, segment; }
129 overrides;
130 /* This structure is 32 bits: */
131 typedef struct { overrides override;
132 u_char default_mode; } fpu_addr_modes;
133 /* PROTECTED has a restricted meaning in the emulator; it is used
134 to signal that the emulator needs to do special things to ensure
135 that protection is respected in a segmented model. */
136 #define PROTECTED 4
137 #define SIXTEEN 1 /* We rely upon this being 1 (true) */
138 #define VM86 SIXTEEN
139 #define PM16 (SIXTEEN | PROTECTED)
140 #define SEG32 PROTECTED
141 extern u_char const data_sizes_16[32];
142
143 #define register_base ((u_char *) registers )
144 #define fpu_register(x) ( * ((FPU_REG *)( register_base + 10 * (x & 7) )) )
145 #define st(x) ( * ((FPU_REG *)( register_base + 10 * ((top+x) & 7) )) )
146
147 #define STACK_OVERFLOW (FPU_stackoverflow(&st_new_ptr))
148 #define NOT_EMPTY(i) (!FPU_empty_i(i))
149
150 #define NOT_EMPTY_ST0 (st0_tag ^ TAG_Empty)
151
152 #define poppop() { FPU_pop(); FPU_pop(); }
153
154 /* push() does not affect the tags */
155 #define push() { top--; }
156
157 #define signbyte(a) (((u_char *)(a))[9])
158 #define getsign(a) (signbyte(a) & 0x80)
159 #define setsign(a,b) { if (b) signbyte(a) |= 0x80; else signbyte(a) &= 0x7f; }
160 #define copysign(a,b) { if (getsign(a)) signbyte(b) |= 0x80; \
161 else signbyte(b) &= 0x7f; }
162 #define changesign(a) { signbyte(a) ^= 0x80; }
163 #define setpositive(a) { signbyte(a) &= 0x7f; }
164 #define setnegative(a) { signbyte(a) |= 0x80; }
165 #define signpositive(a) ( (signbyte(a) & 0x80) == 0 )
166 #define signnegative(a) (signbyte(a) & 0x80)
167
168 static inline void reg_copy(FPU_REG const *x, FPU_REG *y)
169 {
170 *(short *)&(y->exp) = *(const short *)&(x->exp);
171 *(long long *)&(y->sigl) = *(const long long *)&(x->sigl);
172 }
173
174 #define exponent(x) (((*(short *)&((x)->exp)) & 0x7fff) - EXTENDED_Ebias)
175 #define setexponentpos(x,y) { (*(short *)&((x)->exp)) = \
176 ((y) + EXTENDED_Ebias) & 0x7fff; }
177 #define exponent16(x) (*(short *)&((x)->exp))
178 #define setexponent16(x,y) { (*(short *)&((x)->exp)) = (y); }
179 #define addexponent(x,y) { (*(short *)&((x)->exp)) += (y); }
180 #define stdexp(x) { (*(short *)&((x)->exp)) += EXTENDED_Ebias; }
181
182 #define isdenormal(ptr) (exponent(ptr) == EXP_BIAS+EXP_UNDER)
183
184 #define significand(x) ( ((unsigned long long *)&((x)->sigl))[0] )
185
186
187 /*----- Prototypes for functions written in assembler -----*/
188 /* extern void reg_move(FPU_REG *a, FPU_REG *b); */
189
190 asmlinkage int FPU_normalize(FPU_REG *x);
191 asmlinkage int FPU_normalize_nuo(FPU_REG *x);
192 asmlinkage int FPU_u_sub(FPU_REG const *arg1, FPU_REG const *arg2,
193 FPU_REG *answ, unsigned int control_w, u_char sign,
194 int expa, int expb);
195 asmlinkage int FPU_u_mul(FPU_REG const *arg1, FPU_REG const *arg2,
196 FPU_REG *answ, unsigned int control_w, u_char sign,
197 int expon);
198 asmlinkage int FPU_u_div(FPU_REG const *arg1, FPU_REG const *arg2,
199 FPU_REG *answ, unsigned int control_w, u_char sign);
200 asmlinkage int FPU_u_add(FPU_REG const *arg1, FPU_REG const *arg2,
201 FPU_REG *answ, unsigned int control_w, u_char sign,
202 int expa, int expb);
203 asmlinkage int wm_sqrt(FPU_REG *n, int dummy1, int dummy2,
204 unsigned int control_w, u_char sign);
205 asmlinkage unsigned FPU_shrx(void *l, unsigned x);
206 asmlinkage unsigned FPU_shrxs(void *v, unsigned x);
207 asmlinkage unsigned long FPU_div_small(unsigned long long *x, unsigned long y);
208 asmlinkage int FPU_round(FPU_REG *arg, unsigned int extent, int dummy,
209 unsigned int control_w, u_char sign);
210
211 #ifndef MAKING_PROTO
212 #include "fpu_proto.h"
213 #endif
214
215 #endif /* __ASSEMBLY__ */
216
217 #endif /* _FPU_EMU_H_ */
218