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