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_ */