122 lines
4.7 KiB
C
122 lines
4.7 KiB
C
/*---------------------------------------------------------------------------+
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| poly.h |
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| Header file for the FPU-emu poly*.c source files. |
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| Copyright (C) 1994,1999 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@melbpc.org.au |
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| Declarations and definitions for functions operating on Xsig (12-byte |
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| extended-significand) quantities. |
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+---------------------------------------------------------------------------*/
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#ifndef _POLY_H
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#define _POLY_H
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/* This 12-byte structure is used to improve the accuracy of computation
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of transcendental functions.
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Intended to be used to get results better than 8-byte computation
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allows. 9-byte would probably be sufficient.
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*/
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typedef struct {
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unsigned long lsw;
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unsigned long midw;
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unsigned long msw;
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} Xsig;
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asmlinkage void mul64(unsigned long long const *a, unsigned long long const *b,
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unsigned long long *result);
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asmlinkage void polynomial_Xsig(Xsig *, const unsigned long long *x,
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const unsigned long long terms[], const int n);
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asmlinkage void mul32_Xsig(Xsig *, const unsigned long mult);
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asmlinkage void mul64_Xsig(Xsig *, const unsigned long long *mult);
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asmlinkage void mul_Xsig_Xsig(Xsig *dest, const Xsig *mult);
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asmlinkage void shr_Xsig(Xsig *, const int n);
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asmlinkage int round_Xsig(Xsig *);
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asmlinkage int norm_Xsig(Xsig *);
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asmlinkage void div_Xsig(Xsig *x1, const Xsig *x2, const Xsig *dest);
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/* Macro to extract the most significant 32 bits from a long long */
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#define LL_MSW(x) (((unsigned long *)&x)[1])
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/* Macro to initialize an Xsig struct */
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#define MK_XSIG(a,b,c) { c, b, a }
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/* Macro to access the 8 ms bytes of an Xsig as a long long */
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#define XSIG_LL(x) (*(unsigned long long *)&x.midw)
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/*
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Need to run gcc with optimizations on to get these to
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actually be in-line.
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*/
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/* Multiply two fixed-point 32 bit numbers, producing a 32 bit result.
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The answer is the ms word of the product. */
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/* Some versions of gcc make it difficult to stop eax from being clobbered.
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Merely specifying that it is used doesn't work...
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*/
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static inline unsigned long mul_32_32(const unsigned long arg1,
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const unsigned long arg2)
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{
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int retval;
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asm volatile ("mull %2; movl %%edx,%%eax" \
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:"=a" (retval) \
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:"0" (arg1), "g" (arg2) \
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:"dx");
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return retval;
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}
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/* Add the 12 byte Xsig x2 to Xsig dest, with no checks for overflow. */
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static inline void add_Xsig_Xsig(Xsig *dest, const Xsig *x2)
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{
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asm volatile ("movl %1,%%edi; movl %2,%%esi;\n"
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"movl (%%esi),%%eax; addl %%eax,(%%edi);\n"
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"movl 4(%%esi),%%eax; adcl %%eax,4(%%edi);\n"
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"movl 8(%%esi),%%eax; adcl %%eax,8(%%edi);\n"
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:"=g" (*dest):"g" (dest), "g" (x2)
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:"ax","si","di");
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}
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/* Add the 12 byte Xsig x2 to Xsig dest, adjust exp if overflow occurs. */
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/* Note: the constraints in the asm statement didn't always work properly
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with gcc 2.5.8. Changing from using edi to using ecx got around the
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problem, but keep fingers crossed! */
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static inline void add_two_Xsig(Xsig *dest, const Xsig *x2, long int *exp)
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{
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asm volatile ("movl %2,%%ecx; movl %3,%%esi;\n"
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"movl (%%esi),%%eax; addl %%eax,(%%ecx);\n"
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"movl 4(%%esi),%%eax; adcl %%eax,4(%%ecx);\n"
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"movl 8(%%esi),%%eax; adcl %%eax,8(%%ecx);\n"
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"jnc 0f;\n"
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"rcrl 8(%%ecx); rcrl 4(%%ecx); rcrl (%%ecx)\n"
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"movl %4,%%ecx; incl (%%ecx)\n"
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"movl $1,%%eax; jmp 1f;\n"
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"0: xorl %%eax,%%eax;\n"
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"1:\n"
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:"=g" (*exp), "=g" (*dest)
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:"g" (dest), "g" (x2), "g" (exp)
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:"cx","si","ax");
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}
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/* Negate (subtract from 1.0) the 12 byte Xsig */
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/* This is faster in a loop on my 386 than using the "neg" instruction. */
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static inline void negate_Xsig(Xsig *x)
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{
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asm volatile("movl %1,%%esi;\n"
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"xorl %%ecx,%%ecx;\n"
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"movl %%ecx,%%eax; subl (%%esi),%%eax; movl %%eax,(%%esi);\n"
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"movl %%ecx,%%eax; sbbl 4(%%esi),%%eax; movl %%eax,4(%%esi);\n"
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"movl %%ecx,%%eax; sbbl 8(%%esi),%%eax; movl %%eax,8(%%esi);\n"
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:"=g" (*x):"g" (x):"si","ax","cx");
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}
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#endif /* _POLY_H */
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