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