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 /*
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 */
63 extern 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 :"" (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. */
76 extern 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! */
91 extern 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. */
111 extern 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
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