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#define TAG_Error	Const(0x80)	/* probably need to abort */
61
62#define LOADED_DATA	Const(10101)	/* Special st() number to identify
63					   loaded data (not on stack). */
64
65/* A few flags (must be >= 0x10). */
66#define REV             0x10
67#define DEST_RM         0x20
68#define LOADED          0x40
69
70#define FPU_Exception   Const(0x80000000)   /* Added to tag returns. */
71
72
73#ifndef __ASSEMBLY__
74
75#include "fpu_system.h"
76
77#include <asm/sigcontext.h>   /* for struct _fpstate */
78#include <asm/math_emu.h>
79#include <linux/linkage.h>
80
81/*
82#define RE_ENTRANT_CHECKING
83 */
84
85#ifdef RE_ENTRANT_CHECKING
86extern u_char emulating;
87#  define RE_ENTRANT_CHECK_OFF emulating = 0
88#  define RE_ENTRANT_CHECK_ON emulating = 1
89#else
90#  define RE_ENTRANT_CHECK_OFF
91#  define RE_ENTRANT_CHECK_ON
92#endif /* RE_ENTRANT_CHECKING */
93
94#define FWAIT_OPCODE 0x9b
95#define OP_SIZE_PREFIX 0x66
96#define ADDR_SIZE_PREFIX 0x67
97#define PREFIX_CS 0x2e
98#define PREFIX_DS 0x3e
99#define PREFIX_ES 0x26
100#define PREFIX_SS 0x36
101#define PREFIX_FS 0x64
102#define PREFIX_GS 0x65
103#define PREFIX_REPE 0xf3
104#define PREFIX_REPNE 0xf2
105#define PREFIX_LOCK 0xf0
106#define PREFIX_CS_ 1
107#define PREFIX_DS_ 2
108#define PREFIX_ES_ 3
109#define PREFIX_FS_ 4
110#define PREFIX_GS_ 5
111#define PREFIX_SS_ 6
112#define PREFIX_DEFAULT 7
113
114struct address {
115  unsigned int offset;
116  unsigned int selector:16;
117  unsigned int opcode:11;
118  unsigned int empty:5;
119};
120struct fpu__reg {
121  unsigned sigl;
122  unsigned sigh;
123  short exp;
124};
125
126typedef void (*FUNC)(void);
127typedef struct fpu__reg FPU_REG;
128typedef void (*FUNC_ST0)(FPU_REG *st0_ptr, u_char st0_tag);
129typedef struct { u_char address_size, operand_size, segment; }
130        overrides;
131/* This structure is 32 bits: */
132typedef struct { overrides override;
133		 u_char default_mode; } 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
142extern 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
169static 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
188/*----- Prototypes for functions written in assembler -----*/
189/* extern void reg_move(FPU_REG *a, FPU_REG *b); */
190
191asmlinkage int FPU_normalize(FPU_REG *x);
192asmlinkage int FPU_normalize_nuo(FPU_REG *x);
193asmlinkage 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);
196asmlinkage 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);
199asmlinkage int FPU_u_div(FPU_REG const *arg1, FPU_REG const *arg2,
200			 FPU_REG *answ, unsigned int control_w, u_char sign);
201asmlinkage 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);
204asmlinkage int wm_sqrt(FPU_REG *n, int dummy1, int dummy2,
205		       unsigned int control_w, u_char sign);
206asmlinkage unsigned	FPU_shrx(void *l, unsigned x);
207asmlinkage unsigned	FPU_shrxs(void *v, unsigned x);
208asmlinkage unsigned long FPU_div_small(unsigned long long *x, unsigned long y);
209asmlinkage 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