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/*---------------------------------------------------------------------------+

 |  poly.h                                                                   |

 |                                                                           |

 |  Header file for the FPU-emu poly*.c source files.                        |

 |                                                                           |

 | Copyright (C) 1994                                                        |

 |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |

 |                       Australia.  E-mail   billm@vaxc.cc.monash.edu.au    |

 |                                                                           |

 | Declarations and definitions for functions operating on Xsig (12-byte     |

 | extended-significand) quantities.                                         |

 |                                                                           |

 +---------------------------------------------------------------------------*/

#ifndef _POLY_H

#define _POLY_H

/* This 12-byte structure is used to improve the accuracy of computation

   of transcendental functions.

   Intended to be used to get results better than 8-byte computation

   allows. 9-byte would probably be sufficient.

   */

typedef struct {

  unsigned long lsw;

  unsigned long midw;

  unsigned long msw;

} Xsig;

asmlinkage void mul64(unsigned long long const *a, unsigned long long const *b,

                      unsigned long long *result);

asmlinkage void polynomial_Xsig(Xsig *, const unsigned long long *x,

                                const unsigned long long terms[], const int n);

asmlinkage void mul32_Xsig(Xsig *, const unsigned long mult);

asmlinkage void mul64_Xsig(Xsig *, const unsigned long long *mult);

asmlinkage void mul_Xsig_Xsig(Xsig *dest, const Xsig *mult);

asmlinkage void shr_Xsig(Xsig *, const int n);

asmlinkage int round_Xsig(Xsig *);

asmlinkage int norm_Xsig(Xsig *);

asmlinkage void div_Xsig(Xsig *x1, const Xsig *x2, const Xsig *dest);

/* Macro to extract the most significant 32 bits from a long long */

#define LL_MSW(x)     (((unsigned long *)&x)[1])

/* Macro to initialize an Xsig struct */

#define MK_XSIG(a,b,c)     { c, b, a }

/* Macro to access the 8 ms bytes of an Xsig as a long long */

#define XSIG_LL(x)         (*(unsigned long long *)&x.midw)

/*

   Need to run gcc with optimizations on to get these to

   actually be in-line.

   */

/* Multiply two fixed-point 32 bit numbers. */

extern inline void mul_32_32(const unsigned long arg1,

                             const unsigned long arg2,

                             unsigned long *out)

{

  asm volatile ("movl %1,%%eax; mull %2; movl %%edx,%0" \

                :"=g" (*out) \

                :"g" (arg1), "g" (arg2) \

                :"ax","dx");

}

/* Add the 12 byte Xsig x2 to Xsig dest, with no checks for overflow. */

extern inline void add_Xsig_Xsig(Xsig *dest, const Xsig *x2)

{

  asm volatile ("movl %1,%%edi; movl %2,%%esi;

                 movl (%%esi),%%eax; addl %%eax,(%%edi);

                 movl 4(%%esi),%%eax; adcl %%eax,4(%%edi);

                 movl 8(%%esi),%%eax; adcl %%eax,8(%%edi);"

                 :"=g" (*dest):"g" (dest), "g" (x2)

                 :"ax","si","di");

}

/* Add the 12 byte Xsig x2 to Xsig dest, adjust exp if overflow occurs. */

/* Note: the constraints in the asm statement didn't always work properly

   with gcc 2.5.8.  Changing from using edi to using ecx got around the

   problem, but keep fingers crossed! */

extern inline int add_two_Xsig(Xsig *dest, const Xsig *x2, long int *exp)

{

  asm volatile ("movl %2,%%ecx; movl %3,%%esi;

                 movl (%%esi),%%eax; addl %%eax,(%%ecx);

                 movl 4(%%esi),%%eax; adcl %%eax,4(%%ecx);

                 movl 8(%%esi),%%eax; adcl %%eax,8(%%ecx);

                 jnc 0f;

                 rcrl 8(%%ecx); rcrl 4(%%ecx); rcrl (%%ecx)

                 movl %4,%%ecx; incl (%%ecx)

                 movl $1,%%eax; jmp 1f;

                 0: xorl %%eax,%%eax;

                 1:"

                :"=g" (*exp), "=g" (*dest)

                :"g" (dest), "g" (x2), "g" (exp)

                :"cx","si","ax");

}

/* Negate (subtract from 1.0) the 12 byte Xsig */

/* This is faster in a loop on my 386 than using the "neg" instruction. */

extern inline void negate_Xsig(Xsig *x)

{

  asm volatile("movl %1,%%esi; "

               "xorl %%ecx,%%ecx; "

               "movl %%ecx,%%eax; subl (%%esi),%%eax; movl %%eax,(%%esi); "

               "movl %%ecx,%%eax; sbbl 4(%%esi),%%eax; movl %%eax,4(%%esi); "

               "movl %%ecx,%%eax; sbbl 8(%%esi),%%eax; movl %%eax,8(%%esi); "

               :"=g" (*x):"g" (x):"si","ax","cx");

}

#endif _POLY_H