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Diffstat (limited to 'arch/x86/math-emu/poly.h')
| -rw-r--r-- | arch/x86/math-emu/poly.h | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/arch/x86/math-emu/poly.h b/arch/x86/math-emu/poly.h new file mode 100644 index 000000000..fc1c887ca --- /dev/null +++ b/arch/x86/math-emu/poly.h @@ -0,0 +1,115 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/*---------------------------------------------------------------------------+ + | 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 */ |