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 */
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 :""(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. */
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! */
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. */
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
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