arch/x86/math-emu/fpu_emu.h

   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_ */