1/*---------------------------------------------------------------------------+
2 |  poly.h                                                                   |
3 |                                                                           |
4 |  Header file for the FPU-emu poly*.c source files.                        |
5 |                                                                           |
6 | Copyright (C) 1994,1999                                                   |
7 |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
8 |                       Australia.  E-mail   billm@melbpc.org.au            |
9 |                                                                           |
10 | Declarations and definitions for functions operating on Xsig (12-byte     |
11 | extended-significand) quantities.                                         |
12 |                                                                           |
13 +---------------------------------------------------------------------------*/
14
15#ifndef _POLY_H
16#define _POLY_H
17
18/* This 12-byte structure is used to improve the accuracy of computation
19   of transcendental functions.
20   Intended to be used to get results better than 8-byte computation
21   allows. 9-byte would probably be sufficient.
22   */
23typedef struct {
24  unsigned long lsw;
25  unsigned long midw;
26  unsigned long msw;
27} Xsig;
28
29asmlinkage void mul64(unsigned long long const *a, unsigned long long const *b,
30		      unsigned long long *result);
31asmlinkage void polynomial_Xsig(Xsig *, const unsigned long long *x,
32				const unsigned long long terms[], const int n);
33
34asmlinkage void mul32_Xsig(Xsig *, const unsigned long mult);
35asmlinkage void mul64_Xsig(Xsig *, const unsigned long long *mult);
36asmlinkage void mul_Xsig_Xsig(Xsig *dest, const Xsig *mult);
37
38asmlinkage void shr_Xsig(Xsig *, const int n);
39asmlinkage int round_Xsig(Xsig *);
40asmlinkage int norm_Xsig(Xsig *);
41asmlinkage void div_Xsig(Xsig *x1, const Xsig *x2, const Xsig *dest);
42
43/* Macro to extract the most significant 32 bits from a long long */
44#define LL_MSW(x)     (((unsigned long *)&x)[1])
45
46/* Macro to initialize an Xsig struct */
47#define MK_XSIG(a,b,c)     { c, b, a }
48
49/* Macro to access the 8 ms bytes of an Xsig as a long long */
50#define XSIG_LL(x)         (*(unsigned long long *)&x.midw)
51
52
53/*
54   Need to run gcc with optimizations on to get these to
55   actually be in-line.
56   */
57
58/* Multiply two fixed-point 32 bit numbers, producing a 32 bit result.
59   The answer is the ms word of the product. */
60/* Some versions of gcc make it difficult to stop eax from being clobbered.
61   Merely specifying that it is used doesn't work...
62 */
63static inline unsigned long mul_32_32(const unsigned long arg1,
64				      const unsigned long arg2)
65{
66  int retval;
67  asm volatile ("mull %2; movl %%edx,%%eax" \
68		:"=a" (retval) \
69		:"0" (arg1), "g" (arg2) \
70		:"dx");
71  return retval;
72}
73
74
75/* Add the 12 byte Xsig x2 to Xsig dest, with no checks for overflow. */
76static inline void add_Xsig_Xsig(Xsig *dest, const Xsig *x2)
77{
78  asm volatile ("movl %1,%%edi; movl %2,%%esi;
79                 movl (%%esi),%%eax; addl %%eax,(%%edi);
80                 movl 4(%%esi),%%eax; adcl %%eax,4(%%edi);
81                 movl 8(%%esi),%%eax; adcl %%eax,8(%%edi);"
82                 :"=g" (*dest):"g" (dest), "g" (x2)
83                 :"ax","si","di");
84}
85
86
87/* Add the 12 byte Xsig x2 to Xsig dest, adjust exp if overflow occurs. */
88/* Note: the constraints in the asm statement didn't always work properly
89   with gcc 2.5.8.  Changing from using edi to using ecx got around the
90   problem, but keep fingers crossed! */
91static inline void add_two_Xsig(Xsig *dest, const Xsig *x2, long int *exp)
92{
93  asm volatile ("movl %2,%%ecx; movl %3,%%esi;
94                 movl (%%esi),%%eax; addl %%eax,(%%ecx);
95                 movl 4(%%esi),%%eax; adcl %%eax,4(%%ecx);
96                 movl 8(%%esi),%%eax; adcl %%eax,8(%%ecx);
97                 jnc 0f;
98		 rcrl 8(%%ecx); rcrl 4(%%ecx); rcrl (%%ecx)
99                 movl %4,%%ecx; incl (%%ecx)
100                 movl $1,%%eax; jmp 1f;
101                 0: xorl %%eax,%%eax;
102                 1:"
103		:"=g" (*exp), "=g" (*dest)
104		:"g" (dest), "g" (x2), "g" (exp)
105		:"cx","si","ax");
106}
107
108
109/* Negate (subtract from 1.0) the 12 byte Xsig */
110/* This is faster in a loop on my 386 than using the "neg" instruction. */
111static inline void negate_Xsig(Xsig *x)
112{
113  asm volatile("movl %1,%%esi; "
114               "xorl %%ecx,%%ecx; "
115               "movl %%ecx,%%eax; subl (%%esi),%%eax; movl %%eax,(%%esi); "
116               "movl %%ecx,%%eax; sbbl 4(%%esi),%%eax; movl %%eax,4(%%esi); "
117               "movl %%ecx,%%eax; sbbl 8(%%esi),%%eax; movl %%eax,8(%%esi); "
118               :"=g" (*x):"g" (x):"si","ax","cx");
119}
120
121#endif /* _POLY_H */
122