• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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    */
23 typedef struct {
24 	unsigned long lsw;
25 	unsigned long midw;
26 	unsigned long msw;
27 } Xsig;
28 
29 asmlinkage void mul64(unsigned long long const *a, unsigned long long const *b,
30 		      unsigned long long *result);
31 asmlinkage void polynomial_Xsig(Xsig *, const unsigned long long *x,
32 				const unsigned long long terms[], const int n);
33 
34 asmlinkage void mul32_Xsig(Xsig *, const unsigned long mult);
35 asmlinkage void mul64_Xsig(Xsig *, const unsigned long long *mult);
36 asmlinkage void mul_Xsig_Xsig(Xsig *dest, const Xsig *mult);
37 
38 asmlinkage void shr_Xsig(Xsig *, const int n);
39 asmlinkage int round_Xsig(Xsig *);
40 asmlinkage int norm_Xsig(Xsig *);
41 asmlinkage 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    Need to run gcc with optimizations on to get these to
54    actually be in-line.
55    */
56 
57 /* Multiply two fixed-point 32 bit numbers, producing a 32 bit result.
58    The answer is the ms word of the product. */
59 /* Some versions of gcc make it difficult to stop eax from being clobbered.
60    Merely specifying that it is used doesn't work...
61  */
mul_32_32(const unsigned long arg1,const unsigned long arg2)62 static inline unsigned long mul_32_32(const unsigned long arg1,
63 				      const unsigned long arg2)
64 {
65 	int retval;
66 	asm volatile ("mull %2; movl %%edx,%%eax":"=a" (retval)
67 		      :"0"(arg1), "g"(arg2)
68 		      :"dx");
69 	return retval;
70 }
71 
72 /* Add the 12 byte Xsig x2 to Xsig dest, with no checks for overflow. */
add_Xsig_Xsig(Xsig * dest,const Xsig * x2)73 static inline void add_Xsig_Xsig(Xsig *dest, const Xsig *x2)
74 {
75 	asm volatile ("movl %1,%%edi; movl %2,%%esi;\n"
76 		      "movl (%%esi),%%eax; addl %%eax,(%%edi);\n"
77 		      "movl 4(%%esi),%%eax; adcl %%eax,4(%%edi);\n"
78 		      "movl 8(%%esi),%%eax; adcl %%eax,8(%%edi);\n":"=g"
79 		      (*dest):"g"(dest), "g"(x2)
80 		      :"ax", "si", "di");
81 }
82 
83 /* Add the 12 byte Xsig x2 to Xsig dest, adjust exp if overflow occurs. */
84 /* Note: the constraints in the asm statement didn't always work properly
85    with gcc 2.5.8.  Changing from using edi to using ecx got around the
86    problem, but keep fingers crossed! */
add_two_Xsig(Xsig * dest,const Xsig * x2,long int * exp)87 static inline void add_two_Xsig(Xsig *dest, const Xsig *x2, long int *exp)
88 {
89 	asm volatile ("movl %2,%%ecx; movl %3,%%esi;\n"
90 		      "movl (%%esi),%%eax; addl %%eax,(%%ecx);\n"
91 		      "movl 4(%%esi),%%eax; adcl %%eax,4(%%ecx);\n"
92 		      "movl 8(%%esi),%%eax; adcl %%eax,8(%%ecx);\n"
93 		      "jnc 0f;\n"
94 		      "rcrl 8(%%ecx); rcrl 4(%%ecx); rcrl (%%ecx)\n"
95 		      "movl %4,%%ecx; incl (%%ecx)\n"
96 		      "movl $1,%%eax; jmp 1f;\n"
97 		      "0: xorl %%eax,%%eax;\n" "1:\n":"=g" (*exp), "=g"(*dest)
98 		      :"g"(dest), "g"(x2), "g"(exp)
99 		      :"cx", "si", "ax");
100 }
101 
102 /* Negate (subtract from 1.0) the 12 byte Xsig */
103 /* This is faster in a loop on my 386 than using the "neg" instruction. */
negate_Xsig(Xsig * x)104 static inline void negate_Xsig(Xsig *x)
105 {
106 	asm volatile ("movl %1,%%esi;\n"
107 		      "xorl %%ecx,%%ecx;\n"
108 		      "movl %%ecx,%%eax; subl (%%esi),%%eax; movl %%eax,(%%esi);\n"
109 		      "movl %%ecx,%%eax; sbbl 4(%%esi),%%eax; movl %%eax,4(%%esi);\n"
110 		      "movl %%ecx,%%eax; sbbl 8(%%esi),%%eax; movl %%eax,8(%%esi);\n":"=g"
111 		      (*x):"g"(x):"si", "ax", "cx");
112 }
113 
114 #endif /* _POLY_H */
115