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Diffstat (limited to '')
-rw-r--r-- | modules/fdlibm/src/s_tanf.cpp | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/modules/fdlibm/src/s_tanf.cpp b/modules/fdlibm/src/s_tanf.cpp new file mode 100644 index 0000000000..f72d28382b --- /dev/null +++ b/modules/fdlibm/src/s_tanf.cpp @@ -0,0 +1,71 @@ +/* s_tanf.c -- float version of s_tan.c. + * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. + * Optimized by Bruce D. Evans. + */ + +/* + * ==================================================== + * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. + * + * Developed at SunPro, a Sun Microsystems, Inc. business. + * Permission to use, copy, modify, and distribute this + * software is freely granted, provided that this notice + * is preserved. + * ==================================================== + */ + +//#include <sys/cdefs.h> +//__FBSDID("$FreeBSD$"); + +#include <float.h> + +#define INLINE_KERNEL_TANDF +#define INLINE_REM_PIO2F +#include "math_private.h" +#include "e_rem_pio2f.cpp" +#include "k_tanf.cpp" + +/* Small multiples of pi/2 rounded to double precision. */ +static const double +t1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */ +t2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */ +t3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */ +t4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */ + +float +tanf(float x) +{ + double y; + int32_t n, hx, ix; + + GET_FLOAT_WORD(hx,x); + ix = hx & 0x7fffffff; + + if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */ + if(ix<0x39800000) /* |x| < 2**-12 */ + if(((int)x)==0) return x; /* x with inexact if x != 0 */ + return __kernel_tandf(x,1); + } + if(ix<=0x407b53d1) { /* |x| ~<= 5*pi/4 */ + if(ix<=0x4016cbe3) /* |x| ~<= 3pi/4 */ + return __kernel_tandf(x + (hx>0 ? -t1pio2 : t1pio2), -1); + else + return __kernel_tandf(x + (hx>0 ? -t2pio2 : t2pio2), 1); + } + if(ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */ + if(ix<=0x40afeddf) /* |x| ~<= 7*pi/4 */ + return __kernel_tandf(x + (hx>0 ? -t3pio2 : t3pio2), -1); + else + return __kernel_tandf(x + (hx>0 ? -t4pio2 : t4pio2), 1); + } + + /* tan(Inf or NaN) is NaN */ + else if (ix>=0x7f800000) return x-x; + + /* general argument reduction needed */ + else { + n = __ieee754_rem_pio2f(x,&y); + /* integer parameter: 1 -- n even; -1 -- n odd */ + return __kernel_tandf(y,1-((n&1)<<1)); + } +} |