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| poly.h |
| |
| Header file for the FPU-emu poly*.c source files. |
| |
| Copyright (C) 1994,1999 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
| Australia. E-mail billm@melbpc.org.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, producing a 32 bit result.
The answer is the ms word of the product. */
/* Some versions of gcc make it difficult to stop eax from being clobbered.
Merely specifying that it is used doesn't work...
*/
static inline unsigned long mul_32_32(const unsigned long arg1,
const unsigned long arg2)
{
int retval;
asm volatile ("mull %2; movl %%edx,%%eax" \
:"=a" (retval) \
:"0" (arg1), "g" (arg2) \
:"dx");
return retval;
}
/* Add the 12 byte Xsig x2 to Xsig dest, with no checks for overflow. */
static inline void add_Xsig_Xsig(Xsig *dest, const Xsig *x2)
{
asm volatile ("movl %1,%%edi; movl %2,%%esi;\n"
"movl (%%esi),%%eax; addl %%eax,(%%edi);\n"
"movl 4(%%esi),%%eax; adcl %%eax,4(%%edi);\n"
"movl 8(%%esi),%%eax; adcl %%eax,8(%%edi);\n"
:"=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! */
static inline void add_two_Xsig(Xsig *dest, const Xsig *x2, long int *exp)
{
asm volatile ("movl %2,%%ecx; movl %3,%%esi;\n"
"movl (%%esi),%%eax; addl %%eax,(%%ecx);\n"
"movl 4(%%esi),%%eax; adcl %%eax,4(%%ecx);\n"
"movl 8(%%esi),%%eax; adcl %%eax,8(%%ecx);\n"
"jnc 0f;\n"
"rcrl 8(%%ecx); rcrl 4(%%ecx); rcrl (%%ecx)\n"
"movl %4,%%ecx; incl (%%ecx)\n"
"movl $1,%%eax; jmp 1f;\n"
"0: xorl %%eax,%%eax;\n"
"1:\n"
:"=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. */
static inline void negate_Xsig(Xsig *x)
{
asm volatile("movl %1,%%esi;\n"
"xorl %%ecx,%%ecx;\n"
"movl %%ecx,%%eax; subl (%%esi),%%eax; movl %%eax,(%%esi);\n"
"movl %%ecx,%%eax; sbbl 4(%%esi),%%eax; movl %%eax,4(%%esi);\n"
"movl %%ecx,%%eax; sbbl 8(%%esi),%%eax; movl %%eax,8(%%esi);\n"
:"=g" (*x):"g" (x):"si","ax","cx");
}
#endif /* _POLY_H */
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