linux/arch/x86/math-emu/poly.h
Ingo Molnar 3d0d14f983 x86: lindent arch/i386/math-emu
lindent these files:
                                       errors   lines of code   errors/KLOC
 arch/x86/math-emu/                      2236            9424         237.2
 arch/x86/math-emu/                       128            8706          14.7

no other changes. No code changed:

   text    data     bss     dec     hex filename
   5589802  612739 3833856 10036397         9924ad vmlinux.before
   5589802  612739 3833856 10036397         9924ad vmlinux.after

the intent of this patch is to ease the automated tracking of kernel
code quality - it's just much easier for us to maintain it if every file
in arch/x86 is supposed to be clean.

NOTE: it is a known problem of lindent that it causes some style damage
of its own, but it's a safe tool (well, except for the gcc array range
initializers extension), so we did the bulk of the changes via lindent,
and did the manual fixups in a followup patch.

the resulting math-emu code has been tested by Thomas Gleixner on a real
386 DX CPU as well, and it works fine.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:11 +01:00

115 lines
4.6 KiB
C

/*---------------------------------------------------------------------------+
| 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 */