/*---------------------------------------------------------------------------+
   |  fpu_emu.h                                                                |
   |                                                                           |
   | Copyright (C) 1992,1993,1994,1997                                         |
   |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   |                       Australia.  E-mail   billm@suburbia.net             |
   |                                                                           |
   +---------------------------------------------------------------------------*/

  #ifndef _FPU_EMU_H_
  #define _FPU_EMU_H_
  
  /*
   * Define PECULIAR_486 to get a closer approximation to 80486 behaviour,
   * rather than behaviour which appears to be cleaner.
   * This is a matter of opinion: for all I know, the 80486 may simply
   * be complying with the IEEE spec. Maybe one day I'll get to see the
   * spec...
   */
  #define PECULIAR_486
  
  #ifdef __ASSEMBLY__
  #include "fpu_asm.h"
  #define	Const(x)	$##x
  #else
  #define	Const(x)	x
  #endif
  
  #define EXP_BIAS	Const(0)

  #define EXP_OVER	Const(0x4000)	/* smallest invalid large exponent */
  #define	EXP_UNDER	Const(-0x3fff)	/* largest invalid small exponent */
  #define EXP_WAY_UNDER   Const(-0x6000)	/* Below the smallest denormal, but
  					   still a 16 bit nr. */

  #define EXP_Infinity    EXP_OVER
  #define EXP_NaN         EXP_OVER
  
  #define EXTENDED_Ebias Const(0x3fff)

  #define EXTENDED_Emin (-0x3ffe)	/* smallest valid exponent */

  
  #define SIGN_POS	Const(0)
  #define SIGN_NEG	Const(0x80)
  
  #define SIGN_Positive	Const(0)
  #define SIGN_Negative	Const(0x8000)

  /* Keep the order TAG_Valid, TAG_Zero, TW_Denormal */
  /* The following fold to 2 (Special) in the Tag Word */

  #define TW_Denormal     Const(4)	/* De-normal */

  #define TW_Infinity	Const(5)	/* + or - infinity */
  #define	TW_NaN		Const(6)	/* Not a Number */
  #define	TW_Unsupported	Const(7)	/* Not supported by an 80486 */
  
  #define TAG_Valid	Const(0)	/* valid */
  #define TAG_Zero	Const(1)	/* zero */
  #define TAG_Special	Const(2)	/* De-normal, + or - infinity,
  					   or Not a Number */
  #define TAG_Empty	Const(3)	/* empty */

  #define TAG_Error	Const(0x80)	/* probably need to abort */

  
  #define LOADED_DATA	Const(10101)	/* Special st() number to identify
  					   loaded data (not on stack). */
  
  /* A few flags (must be >= 0x10). */
  #define REV             0x10
  #define DEST_RM         0x20
  #define LOADED          0x40

  #define FPU_Exception   Const(0x80000000)	/* Added to tag returns. */

  
  #ifndef __ASSEMBLY__
  
  #include "fpu_system.h"

  #include <asm/sigcontext.h>	/* for struct _fpstate */

  #include <asm/math_emu.h>
  #include <linux/linkage.h>
  
  /*
  #define RE_ENTRANT_CHECKING
   */
  
  #ifdef RE_ENTRANT_CHECKING
  extern u_char emulating;
  #  define RE_ENTRANT_CHECK_OFF emulating = 0
  #  define RE_ENTRANT_CHECK_ON emulating = 1
  #else
  #  define RE_ENTRANT_CHECK_OFF
  #  define RE_ENTRANT_CHECK_ON
  #endif /* RE_ENTRANT_CHECKING */
  
  #define FWAIT_OPCODE 0x9b
  #define OP_SIZE_PREFIX 0x66
  #define ADDR_SIZE_PREFIX 0x67
  #define PREFIX_CS 0x2e
  #define PREFIX_DS 0x3e
  #define PREFIX_ES 0x26
  #define PREFIX_SS 0x36
  #define PREFIX_FS 0x64
  #define PREFIX_GS 0x65
  #define PREFIX_REPE 0xf3
  #define PREFIX_REPNE 0xf2
  #define PREFIX_LOCK 0xf0
  #define PREFIX_CS_ 1
  #define PREFIX_DS_ 2
  #define PREFIX_ES_ 3
  #define PREFIX_FS_ 4
  #define PREFIX_GS_ 5
  #define PREFIX_SS_ 6
  #define PREFIX_DEFAULT 7
  
  struct address {

  	unsigned int offset;
  	unsigned int selector:16;
  	unsigned int opcode:11;
  	unsigned int empty:5;

  };
  struct fpu__reg {

  	unsigned sigl;
  	unsigned sigh;
  	short exp;

  };

  typedef void (*FUNC) (void);

  typedef struct fpu__reg FPU_REG;

  typedef void (*FUNC_ST0) (FPU_REG *st0_ptr, u_char st0_tag);

  typedef struct {
  	u_char address_size, operand_size, segment;
  } overrides;

  /* This structure is 32 bits: */

  typedef struct {
  	overrides override;
  	u_char default_mode;
  } fpu_addr_modes;

  /* PROTECTED has a restricted meaning in the emulator; it is used
     to signal that the emulator needs to do special things to ensure
     that protection is respected in a segmented model. */
  #define PROTECTED 4

  #define SIXTEEN   1		/* We rely upon this being 1 (true) */

  #define VM86      SIXTEEN
  #define PM16      (SIXTEEN | PROTECTED)
  #define SEG32     PROTECTED
  extern u_char const data_sizes_16[32];
  
  #define register_base ((u_char *) registers )
  #define fpu_register(x)  ( * ((FPU_REG *)( register_base + 10 * (x & 7) )) )
  #define	st(x)      ( * ((FPU_REG *)( register_base + 10 * ((top+x) & 7) )) )
  
  #define	STACK_OVERFLOW	(FPU_stackoverflow(&st_new_ptr))
  #define	NOT_EMPTY(i)	(!FPU_empty_i(i))
  
  #define	NOT_EMPTY_ST0	(st0_tag ^ TAG_Empty)
  
  #define poppop() { FPU_pop(); FPU_pop(); }
  
  /* push() does not affect the tags */
  #define push()	{ top--; }
  
  #define signbyte(a) (((u_char *)(a))[9])
  #define getsign(a) (signbyte(a) & 0x80)
  #define setsign(a,b) { if (b) signbyte(a) |= 0x80; else signbyte(a) &= 0x7f; }
  #define copysign(a,b) { if (getsign(a)) signbyte(b) |= 0x80; \
                          else signbyte(b) &= 0x7f; }
  #define changesign(a) { signbyte(a) ^= 0x80; }
  #define setpositive(a) { signbyte(a) &= 0x7f; }
  #define setnegative(a) { signbyte(a) |= 0x80; }
  #define signpositive(a) ( (signbyte(a) & 0x80) == 0 )
  #define signnegative(a) (signbyte(a) & 0x80)

  static inline void reg_copy(FPU_REG const *x, FPU_REG *y)

  {

  	*(short *)&(y->exp) = *(const short *)&(x->exp);
  	*(long long *)&(y->sigl) = *(const long long *)&(x->sigl);

  }
  
  #define exponent(x)  (((*(short *)&((x)->exp)) & 0x7fff) - EXTENDED_Ebias)
  #define setexponentpos(x,y) { (*(short *)&((x)->exp)) = \
    ((y) + EXTENDED_Ebias) & 0x7fff; }
  #define exponent16(x)         (*(short *)&((x)->exp))
  #define setexponent16(x,y)  { (*(short *)&((x)->exp)) = (y); }
  #define addexponent(x,y)    { (*(short *)&((x)->exp)) += (y); }
  #define stdexp(x)           { (*(short *)&((x)->exp)) += EXTENDED_Ebias; }
  
  #define isdenormal(ptr)   (exponent(ptr) == EXP_BIAS+EXP_UNDER)
  
  #define significand(x) ( ((unsigned long long *)&((x)->sigl))[0] )

  /*----- Prototypes for functions written in assembler -----*/
  /* extern void reg_move(FPU_REG *a, FPU_REG *b); */

  asmlinkage int FPU_normalize(FPU_REG *x);
  asmlinkage int FPU_normalize_nuo(FPU_REG *x);

  asmlinkage int FPU_u_sub(FPU_REG const *arg1, FPU_REG const *arg2,

  			 FPU_REG * answ, unsigned int control_w, u_char sign,

  			 int expa, int expb);
  asmlinkage int FPU_u_mul(FPU_REG const *arg1, FPU_REG const *arg2,

  			 FPU_REG * answ, unsigned int control_w, u_char sign,

  			 int expon);
  asmlinkage int FPU_u_div(FPU_REG const *arg1, FPU_REG const *arg2,

  			 FPU_REG * answ, unsigned int control_w, u_char sign);

  asmlinkage int FPU_u_add(FPU_REG const *arg1, FPU_REG const *arg2,

  			 FPU_REG * answ, unsigned int control_w, u_char sign,

  			 int expa, int expb);

  asmlinkage int wm_sqrt(FPU_REG *n, int dummy1, int dummy2,

  		       unsigned int control_w, u_char sign);

  asmlinkage unsigned FPU_shrx(void *l, unsigned x);
  asmlinkage unsigned FPU_shrxs(void *v, unsigned x);

  asmlinkage unsigned long FPU_div_small(unsigned long long *x, unsigned long y);

  asmlinkage int FPU_round(FPU_REG *arg, unsigned int extent, int dummy,

  			 unsigned int control_w, u_char sign);
  
  #ifndef MAKING_PROTO
  #include "fpu_proto.h"
  #endif
  
  #endif /* __ASSEMBLY__ */
  
  #endif /* _FPU_EMU_H_ */