100 lines
3.0 KiB
TeX
100 lines
3.0 KiB
TeX
@node machine,,syscalls,Top
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@chapter NEC V70 Specific Functions
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The NEC V70 has machine instructions for fast IEEE floating-point
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arithmetic, including operations normally provided by the library.
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When you use the @file{/usr/include/fastmath.h} header file, the
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names of several library math functions are redefined to call the
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@code{fastmath} routine (using the corresponding V70 machine instructions)
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whenever possible.
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For example,
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@example
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#include <fastmath.h>
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double sqsin(x)
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double x;
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@{
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return sin(x*x);
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@}
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@end example
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expands into the code
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@example
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@dots{}
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double sqsin(x)
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double x;
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@{
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return fast_sin(x*x);
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@}
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@end example
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The library has an entry @code{fast_sin} which uses the machine
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instruction @code{fsin.l} to perform the operation. Note that the
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built-in instructions cannot set @code{errno}
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in the same way that the C coded functions do. Refer to a V70
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instruction manual to see how errors are generated and handled.
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Also, the library provides true @code{float} entry points. The
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@code{fast_sinf} entry point really performs a @code{fsin.s}
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operation. Because of this, the instructions are only useful when
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using code compiled with an ANSI C compiler. The prototypes
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and definitions for the floating-point versions of the math library
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routines are only defined if compiling a module with an ANSI C
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compiler.
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@page
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@section Entry points
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The functions provided by @file{fastmath.h} are
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@example
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double fast_sin(double); /* fsin.l */
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double fast_cos(double); /* fcos.l */
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double fast_tan(double); /* ftan.l */
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double fast_asin(double); /* fasin.l */
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double fast_acos(double); /* facos.l */
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double fast_atan(double); /* fatan.l */
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double fast_sinh(double); /* fsinh.l */
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double fast_cosh(double); /* fcosh.l */
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double fast_tanh(double); /* ftanh.l */
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double fast_asinh(double); /* fasinh.l */
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double fast_acosh(double); /* facosh.l */
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double fast_atanh(double); /* fatanh.l */
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double fast_fabs(double); /* fabs.l */
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double fast_sqrt(double); /* fsqrt.l */
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double fast_exp2(double); /* fexp2.l */
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double fast_exp10(double); /* fexp10.l */
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double fast_expe(double); /* fexpe.l */
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double fast_log10(double); /* flog10.l */
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double fast_log2(double); /* flog2.l */
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double fast_loge(double); /* floge.l */
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float fast_sinf(float); /* fsin.s */
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float fast_cosf(float); /* fcos.s */
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float fast_tanf(float); /* ftan.s */
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float fast_asinf(float); /* fasin.s */
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float fast_acosf(float); /* facos.s */
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float fast_atanf(float); /* fatan.s */
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float fast_sinhf(float); /* fsinh.s */
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float fast_coshf(float); /* fcosh.s */
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float fast_tanhf(float); /* ftanh.s */
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float fast_asinhf(float); /* fasinh.s */
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float fast_acoshf(float); /* facosh.s */
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float fast_atanhf(float); /* fatanh.s */
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float fast_fabsf(float); /* fabs.s */
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float fast_sqrtf(float); /* fsqrt.s */
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float fast_exp2f(float); /* fexp2.s */
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float fast_exp10f(float); /* fexp10.s */
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float fast_expef(float); /* fexpe.s */
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float fast_log10f(float); /* flog10.s */
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float fast_log2f(float); /* flog2.s */
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float fast_logef(float); /* floge.s */
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@end example
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