1 /* s_tanf.c -- float version of s_tan.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian (at) cygnus.com. 3 * Optimized by Bruce D. Evans. 4 */ 5 6 /* 7 * ==================================================== 8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 9 * 10 * Developed at SunPro, a Sun Microsystems, Inc. business. 11 * Permission to use, copy, modify, and distribute this 12 * software is freely granted, provided that this notice 13 * is preserved. 14 * ==================================================== 15 */ 16 17 #include <sys/cdefs.h> 18 __FBSDID("$FreeBSD$"); 19 20 #include <float.h> 21 22 #include "math.h" 23 #define INLINE_KERNEL_TANDF 24 #define INLINE_REM_PIO2F 25 #include "math_private.h" 26 #include "e_rem_pio2f.c" 27 #include "k_tanf.c" 28 29 /* Small multiples of pi/2 rounded to double precision. */ 30 static const double 31 t1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */ 32 t2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */ 33 t3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */ 34 t4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */ 35 36 float 37 tanf(float x) 38 { 39 double y; 40 int32_t n, hx, ix; 41 42 GET_FLOAT_WORD(hx,x); 43 ix = hx & 0x7fffffff; 44 45 if(ix <= 0x3f490fda) { /* |x| ~<= pi/4 */ 46 if(ix<0x39800000) /* |x| < 2**-12 */ 47 if(((int)x)==0) return x; /* x with inexact if x != 0 */ 48 return __kernel_tandf(x,1); 49 } 50 if(ix<=0x407b53d1) { /* |x| ~<= 5*pi/4 */ 51 if(ix<=0x4016cbe3) /* |x| ~<= 3pi/4 */ 52 return __kernel_tandf(x + (hx>0 ? -t1pio2 : t1pio2), -1); 53 else 54 return __kernel_tandf(x + (hx>0 ? -t2pio2 : t2pio2), 1); 55 } 56 if(ix<=0x40e231d5) { /* |x| ~<= 9*pi/4 */ 57 if(ix<=0x40afeddf) /* |x| ~<= 7*pi/4 */ 58 return __kernel_tandf(x + (hx>0 ? -t3pio2 : t3pio2), -1); 59 else 60 return __kernel_tandf(x + (hx>0 ? -t4pio2 : t4pio2), 1); 61 } 62 63 /* tan(Inf or NaN) is NaN */ 64 else if (ix>=0x7f800000) return x-x; 65 66 /* general argument reduction needed */ 67 else { 68 n = __ieee754_rem_pio2f(x,&y); 69 /* integer parameter: 1 -- n even; -1 -- n odd */ 70 return __kernel_tandf(y,1-((n&1)<<1)); 71 } 72 } 73
