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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
84extern 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
112struct address {
113 unsigned int offset;
114 unsigned int selector:16;
115 unsigned int opcode:11;
116 unsigned int empty:5;
117};
118struct fpu__reg {
119 unsigned sigl;
120 unsigned sigh;
121 short exp;
122};
123
124typedef void (*FUNC) (void);
125typedef struct fpu__reg FPU_REG;
126typedef void (*FUNC_ST0) (FPU_REG *st0_ptr, u_char st0_tag);
127typedef struct {
128 u_char address_size, operand_size, segment;
129} overrides;
130/* This structure is 32 bits: */
131typedef 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
143extern 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
170static 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
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_ */