From 13c28e8cbb1e13e044cd68be879a85f1f6b75021 Mon Sep 17 00:00:00 2001 From: Wincent Balin Date: Mon, 17 Aug 2009 15:39:08 +0000 Subject: PDBox: Simplified some float math functions. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22381 a1c6a512-1295-4272-9138-f99709370657 --- apps/plugins/pdbox/pdbox-func.c | 856 ++-------------------------------------- 1 file changed, 41 insertions(+), 815 deletions(-) (limited to 'apps/plugins/pdbox') diff --git a/apps/plugins/pdbox/pdbox-func.c b/apps/plugins/pdbox/pdbox-func.c index b019959790..42427a69c3 100644 --- a/apps/plugins/pdbox/pdbox-func.c +++ b/apps/plugins/pdbox/pdbox-func.c @@ -582,284 +582,55 @@ float rb_log10(float x) } -/* Power function, - Taken from glibc-2.8 */ - -int rb_isinf(float x) -{ - int32_t ix, t; - GET_FLOAT_WORD(ix,x); - t = ix & 0x7fffffff; - t ^= 0x7f800000; - t |= -t; - return ~(t >> 31) & (ix >> 30); -} - -float rb_copysignf(float x, float y) -{ - uint32_t ix, iy; - GET_FLOAT_WORD(ix,x); - GET_FLOAT_WORD(iy,y); - SET_FLOAT_WORD(x,(ix&0x7fffffff)|(iy&0x80000000)); - return x; -} - +/* Power function, taken from glibc-2.8 and dietlibc-0.32 */ static const float huge = 1.0e+30, tiny = 1.0e-30, -twom25 = 2.9802322388e-08; /* 0x33000000 */ +one = 1.0f; -float rb_scalbnf(float x, int n) +float rb_pow(float x, float y) { - int32_t k, ix; - GET_FLOAT_WORD(ix,x); - k = (ix&0x7f800000)>>23; /* extract exponent */ - if (k==0) { /* 0 or subnormal x */ - if ((ix&0x7fffffff)==0) return x; /* +-0 */ - x *= two25; - GET_FLOAT_WORD(ix,x); - k = ((ix&0x7f800000)>>23) - 25; - } - if (k==0xff) return x+x; /* NaN or Inf */ - k = k+n; - if (n> 50000 || k > 0xfe) - return huge*rb_copysignf(huge,x); /* overflow */ - if (n< -50000) - return tiny*rb_copysignf(tiny,x); /*underflow*/ - if (k > 0) /* normal result */ - {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;} - if (k <= -25) - return tiny*rb_copysignf(tiny,x); /*underflow*/ - k += 25; /* subnormal result */ - SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); - return x*twom25; -} + unsigned int e; + float result; + /* Special cases 0^x */ + if(x == 0.0f) + { + if(y > 0.0f) + return 0.0f; + else if(y == 0.0f) + return 1.0f; + else + return 1.0f / x; + } -static const float -bp[] = {1.0, 1.5,}, -dp_h[] = { 0.0, 5.84960938e-01,}, /* 0x3f15c000 */ -dp_l[] = { 0.0, 1.56322085e-06,}, /* 0x35d1cfdc */ -one = 1.0, -two = 2.0, -two24 = 16777216.0, /* 0x4b800000 */ - /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */ -L1 = 6.0000002384e-01, /* 0x3f19999a */ -L2 = 4.2857143283e-01, /* 0x3edb6db7 */ -L3 = 3.3333334327e-01, /* 0x3eaaaaab */ -L4 = 2.7272811532e-01, /* 0x3e8ba305 */ -L5 = 2.3066075146e-01, /* 0x3e6c3255 */ -L6 = 2.0697501302e-01, /* 0x3e53f142 */ -P1 = 1.6666667163e-01, /* 0x3e2aaaab */ -P2 = -2.7777778450e-03, /* 0xbb360b61 */ -P3 = 6.6137559770e-05, /* 0x388ab355 */ -P4 = -1.6533901999e-06, /* 0xb5ddea0e */ -P5 = 4.1381369442e-08; /* 0x3331bb4c */ + /* Special case x^n where n is integer */ + if(y == (int) (e = (int) y)) + { + if((int) e < 0) + { + e = -e; + x = 1.0f / x; + } -static const float -lg2 = 6.9314718246e-01, /* 0x3f317218 */ -lg2_h = 6.93145752e-01, /* 0x3f317200 */ -lg2_l = 1.42860654e-06, /* 0x35bfbe8c */ -ovt = 4.2995665694e-08, /* -(128-log2(ovfl+.5ulp)) */ -cp = 9.6179670095e-01, /* 0x3f76384f =2/(3ln2) */ -cp_h = 9.6179199219e-01, /* 0x3f763800 =head of cp */ -cp_l = 4.7017383622e-06, /* 0x369dc3a0 =tail of cp_h */ -ivln2 = 1.4426950216e+00, /* 0x3fb8aa3b =1/ln2 */ -ivln2_h = 1.4426879883e+00, /* 0x3fb8aa00 =16b 1/ln2*/ -ivln2_l = 7.0526075433e-06; /* 0x36eca570 =1/ln2 tail*/ + result = 1.0f; -float rb_pow(float x, float y) -{ - float z, ax, z_h, z_l, p_h, p_l; - float y1, t1, t2, r, s, t, u, v, w; - int32_t i, j, k, yisint, n; - int32_t hx, hy, ix, iy, is; - - GET_FLOAT_WORD(hx,x); - GET_FLOAT_WORD(hy,y); - ix = hx&0x7fffffff; - iy = hy&0x7fffffff; - - /* y==zero: x**0 = 1 */ - if(iy==0) return one; - - /* x==+-1 */ - if(x == 1.0) return one; - if(x == -1.0 && rb_isinf(y)) return one; - - /* +-NaN return x+y */ - if(ix > 0x7f800000 || iy > 0x7f800000) - return x+y; - - /* determine if y is an odd int when x < 0 - * yisint = 0 ... y is not an integer - * yisint = 1 ... y is an odd int - * yisint = 2 ... y is an even int - */ - yisint = 0; - if(hx<0) { - if(iy>=0x4b800000) yisint = 2; /* even integer y */ - else if(iy>=0x3f800000) { - k = (iy>>23)-0x7f; /* exponent */ - j = iy>>(23-k); - if((j<<(23-k))==iy) yisint = 2-(j&1); - } - } + while(1) + { + if(e & 1) + result *= x; - /* special value of y */ - if (iy==0x7f800000) { /* y is +-inf */ - if (ix==0x3f800000) - return y - y; /* inf**+-1 is NaN */ - else if (ix > 0x3f800000)/* (|x|>1)**+-inf = inf,0 */ - return (hy>=0)? y: zero; - else /* (|x|<1)**-,+inf = inf,0 */ - return (hy<0)?-y: zero; - } - if(iy==0x3f800000) { /* y is +-1 */ - if(hy<0) return one/x; else return x; - } - if(hy==0x40000000) return x*x; /* y is 2 */ - if(hy==0x3f000000) { /* y is 0.5 */ - if(hx>=0) /* x >= +0 */ - return rb_sqrt(x); - } + if((e >>= 1) == 0) + break; - ax = rb_fabs(x); - /* special value of x */ - if(ix==0x7f800000||ix==0||ix==0x3f800000){ - z = ax; /*x is +-0,+-inf,+-1*/ - if(hy<0) z = one/z; /* z = (1/|x|) */ - if(hx<0) { - if(((ix-0x3f800000)|yisint)==0) { - z = (z-z)/(z-z); /* (-1)**non-int is NaN */ - } else if(yisint==1) - z = -z; /* (x<0)**odd = -(|x|**odd) */ + x *= x; } - return z; - } - /* (x<0)**(non-int) is NaN */ - if(((((uint32_t)hx>>31)-1)|yisint)==0) return (x-x)/(x-x); - - /* |y| is huge */ - if(iy>0x4d000000) { /* if |y| > 2**27 */ - /* over/underflow if x is not close to one */ - if(ix<0x3f7ffff8) return (hy<0)? huge*huge:tiny*tiny; - if(ix>0x3f800007) return (hy>0)? huge*huge:tiny*tiny; - /* now |1-x| is tiny <= 2**-20, suffice to compute - log(x) by x-x^2/2+x^3/3-x^4/4 */ - t = x-1; /* t has 20 trailing zeros */ - w = (t*t)*((float)0.5-t*((float)0.333333333333-t*(float)0.25)); - u = ivln2_h*t; /* ivln2_h has 16 sig. bits */ - v = t*ivln2_l-w*ivln2; - t1 = u+v; - GET_FLOAT_WORD(is,t1); - SET_FLOAT_WORD(t1,is&0xfffff000); - t2 = v-(t1-u); - } else { - float s2, s_h, s_l, t_h, t_l; - n = 0; - /* take care subnormal number */ - if(ix<0x00800000) - {ax *= two24; n -= 24; GET_FLOAT_WORD(ix,ax); } - n += ((ix)>>23)-0x7f; - j = ix&0x007fffff; - /* determine interval */ - ix = j|0x3f800000; /* normalize ix */ - if(j<=0x1cc471) k=0; /* |x|>1)|0x20000000)+0x0040000+(k<<21)); - t_l = ax - (t_h-bp[k]); - s_l = v*((u-s_h*t_h)-s_h*t_l); - /* compute log(ax) */ - s2 = s*s; - r = s2*s2*(L1+s2*(L2+s2*(L3+s2*(L4+s2*(L5+s2*L6))))); - r += s_l*(s_h+s); - s2 = s_h*s_h; - t_h = (float)3.0+s2+r; - GET_FLOAT_WORD(is,t_h); - SET_FLOAT_WORD(t_h,is&0xfffff000); - t_l = r-((t_h-(float)3.0)-s2); - /* u+v = s*(1+...) */ - u = s_h*t_h; - v = s_l*t_h+t_l*s; - /* 2/(3log2)*(s+...) */ - p_h = u+v; - GET_FLOAT_WORD(is,p_h); - SET_FLOAT_WORD(p_h,is&0xfffff000); - p_l = v-(p_h-u); - z_h = cp_h*p_h; /* cp_h+cp_l = 2/(3*log2) */ - z_l = cp_l*p_h+p_l*cp+dp_l[k]; - /* log2(ax) = (s+..)*2/(3*log2) = n + dp_h + z_h + z_l */ - t = (float)n; - t1 = (((z_h+z_l)+dp_h[k])+t); - GET_FLOAT_WORD(is,t1); - SET_FLOAT_WORD(t1,is&0xfffff000); - t2 = z_l-(((t1-t)-dp_h[k])-z_h); + return result; } - s = one; /* s (sign of result -ve**odd) = -1 else = 1 */ - if(((((uint32_t)hx>>31)-1)|(yisint-1))==0) - s = -one; /* (-ve)**(odd int) */ - - /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */ - GET_FLOAT_WORD(is,y); - SET_FLOAT_WORD(y1,is&0xfffff000); - p_l = (y-y1)*t1+y*t2; - p_h = y1*t1; - z = p_l+p_h; - GET_FLOAT_WORD(j,z); - if (j>0x43000000) /* if z > 128 */ - return s*huge*huge; /* overflow */ - else if (j==0x43000000) { /* if z == 128 */ - if(p_l+ovt>z-p_h) return s*huge*huge; /* overflow */ - } - else if ((j&0x7fffffff)>0x43160000) /* z <= -150 */ - return s*tiny*tiny; /* underflow */ - else if ((uint32_t) j==0xc3160000){ /* z == -150 */ - if(p_l<=z-p_h) return s*tiny*tiny; /* underflow */ - } - /* - * compute 2**(p_h+p_l) - */ - i = j&0x7fffffff; - k = (i>>23)-0x7f; - n = 0; - if(i>0x3f000000) { /* if |z| > 0.5, set n = [z+0.5] */ - n = j+(0x00800000>>(k+1)); - k = ((n&0x7fffffff)>>23)-0x7f; /* new k for n */ - SET_FLOAT_WORD(t,n&~(0x007fffff>>k)); - n = ((n&0x007fffff)|0x00800000)>>(23-k); - if(j<0) n = -n; - p_h -= t; - } - t = p_l+p_h; - GET_FLOAT_WORD(is,t); - SET_FLOAT_WORD(t,is&0xfffff000); - u = t*lg2_h; - v = (p_l-(t-p_h))*lg2+t*lg2_l; - z = u+v; - w = v-(z-u); - t = z*z; - t1 = z - t*(P1+t*(P2+t*(P3+t*(P4+t*P5)))); - r = (z*t1)/(t1-two)-(w+z*w); - z = one-(r-z); - GET_FLOAT_WORD(j,z); - j += (n<<23); - if((j>>23)<=0) z = rb_scalbnf(z,n); /* subnormal output */ - else SET_FLOAT_WORD(z,j); - return s*z; + /* Normal case */ + return rb_exp(rb_log(x) * y); } @@ -930,14 +701,10 @@ float rb_sqrt(float x) return z; } -/* Absolute value, - taken from glibc-2.8 */ +/* Absolute value, simple calculus */ float rb_fabs(float x) { - uint32_t ix; - GET_FLOAT_WORD(ix,x); - SET_FLOAT_WORD(x,ix&0x7fffffff); - return x; + return (x < 0.0f) ? -x : x; } /* Arc tangent, @@ -1093,559 +860,18 @@ float rb_atan2(float x, float y) } -/* Sine hyperbolic, - taken from glibc-2.8 */ - -static const float -o_threshold = 8.8721679688e+01,/* 0x42b17180 */ -invln2 = 1.4426950216e+00,/* 0x3fb8aa3b */ - /* scaled coefficients related to expm1 */ -Q1 = -3.3333335072e-02, /* 0xbd088889 */ -Q2 = 1.5873016091e-03, /* 0x3ad00d01 */ -Q3 = -7.9365076090e-05, /* 0xb8a670cd */ -Q4 = 4.0082177293e-06, /* 0x36867e54 */ -Q5 = -2.0109921195e-07; /* 0xb457edbb */ - -float rb_expm1(float x) -{ - float y,hi,lo,c=0,t,e,hxs,hfx,r1; - int32_t k,xsb; - uint32_t hx; - - GET_FLOAT_WORD(hx,x); - xsb = hx&0x80000000; /* sign bit of x */ - if(xsb==0) y=x; else y= -x; /* y = |x| */ - hx &= 0x7fffffff; /* high word of |x| */ - - /* filter out huge and non-finite argument */ - if(hx >= 0x4195b844) { /* if |x|>=27*ln2 */ - if(hx >= 0x42b17218) { /* if |x|>=88.721... */ - if(hx>0x7f800000) - return x+x; /* NaN */ - if(hx==0x7f800000) - return (xsb==0)? x:-1.0;/* exp(+-inf)={inf,-1} */ - if(x > o_threshold) return huge*huge; /* overflow */ - } - if(xsb!=0) { /* x < -27*ln2, return -1.0 with inexact */ - if(x+tiny<(float)0.0) /* raise inexact */ - return tiny-one; /* return -1 */ - } - } - - /* argument reduction */ - if(hx > 0x3eb17218) { /* if |x| > 0.5 ln2 */ - if(hx < 0x3F851592) { /* and |x| < 1.5 ln2 */ - if(xsb==0) - {hi = x - ln2_hi; lo = ln2_lo; k = 1;} - else - {hi = x + ln2_hi; lo = -ln2_lo; k = -1;} - } else { - k = invln2*x+((xsb==0)?(float)0.5:(float)-0.5); - t = k; - hi = x - t*ln2_hi; /* t*ln2_hi is exact here */ - lo = t*ln2_lo; - } - x = hi - lo; - c = (hi-x)-lo; - } - else if(hx < 0x33000000) { /* when |x|<2**-25, return x */ - t = huge+x; /* return x with inexact flags when x!=0 */ - return x - (t-(huge+x)); - } - else k = 0; - - /* x is now in primary range */ - hfx = (float)0.5*x; - hxs = x*hfx; - r1 = one+hxs*(Q1+hxs*(Q2+hxs*(Q3+hxs*(Q4+hxs*Q5)))); - t = (float)3.0-r1*hfx; - e = hxs*((r1-t)/((float)6.0 - x*t)); - if(k==0) return x - (x*e-hxs); /* c is 0 */ - else { - e = (x*(e-c)-c); - e -= hxs; - if(k== -1) return (float)0.5*(x-e)-(float)0.5; - if(k==1) { - if(x < (float)-0.25) return -(float)2.0*(e-(x+(float)0.5)); - else return one+(float)2.0*(x-e); - } - if (k <= -2 || k>56) { /* suffice to return exp(x)-1 */ - int32_t i; - y = one-(e-x); - GET_FLOAT_WORD(i,y); - SET_FLOAT_WORD(y,i+(k<<23)); /* add k to y's exponent */ - return y-one; - } - t = one; - if(k<23) { - int32_t i; - SET_FLOAT_WORD(t,0x3f800000 - (0x1000000>>k)); /* t=1-2^-k */ - y = t-(e-x); - GET_FLOAT_WORD(i,y); - SET_FLOAT_WORD(y,i+(k<<23)); /* add k to y's exponent */ - } else { - int32_t i; - SET_FLOAT_WORD(t,((0x7f-k)<<23)); /* 2^-k */ - y = x-(e+t); - y += one; - GET_FLOAT_WORD(i,y); - SET_FLOAT_WORD(y,i+(k<<23)); /* add k to y's exponent */ - } - } - return y; -} - -static const float shuge = 1.0e37; - +/* Sine hyperbolic, taken from dietlibc-0.32 */ float rb_sinh(float x) { - float t,w,h; - int32_t ix,jx; - - GET_FLOAT_WORD(jx,x); - ix = jx&0x7fffffff; - - /* x is INF or NaN */ - if(ix>=0x7f800000) return x+x; - - h = 0.5; - if (jx<0) h = -h; - /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */ - if (ix < 0x41b00000) { /* |x|<22 */ - if (ix<0x31800000) /* |x|<2**-28 */ - if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */ - t = rb_expm1(rb_fabs(x)); - if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one)); - return h*(t+t/(t+one)); - } - - /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */ - if (ix < 0x42b17180) return h*rb_exp(rb_fabs(x)); - - /* |x| in [log(maxdouble), overflowthresold] */ - if (ix<=0x42b2d4fc) { - w = rb_exp((float)0.5*rb_fabs(x)); - t = h*w; - return t*w; - } - - /* |x| > overflowthresold, sinh(x) overflow */ - return x*shuge; -} - - -/* Tangent, - taken from glibc-2.8 */ - -static const float -pio4 = 7.8539812565e-01, /* 0x3f490fda */ -pio4lo= 3.7748947079e-08, /* 0x33222168 */ -T[] = { - 3.3333334327e-01, /* 0x3eaaaaab */ - 1.3333334029e-01, /* 0x3e088889 */ - 5.3968254477e-02, /* 0x3d5d0dd1 */ - 2.1869488060e-02, /* 0x3cb327a4 */ - 8.8632395491e-03, /* 0x3c11371f */ - 3.5920790397e-03, /* 0x3b6b6916 */ - 1.4562094584e-03, /* 0x3abede48 */ - 5.8804126456e-04, /* 0x3a1a26c8 */ - 2.4646313977e-04, /* 0x398137b9 */ - 7.8179444245e-05, /* 0x38a3f445 */ - 7.1407252108e-05, /* 0x3895c07a */ - -1.8558637748e-05, /* 0xb79bae5f */ - 2.5907305826e-05, /* 0x37d95384 */ -}; - -float kernel_tan(float x, float y, int iy) -{ - float z,r,v,w,s; - int32_t ix,hx; - GET_FLOAT_WORD(hx,x); - ix = hx&0x7fffffff; /* high word of |x| */ - if(ix<0x31800000) /* x < 2**-28 */ - {if((int)x==0) { /* generate inexact */ - if((ix|(iy+1))==0) return one/rb_fabs(x); - else return (iy==1)? x: -one/x; - } - } - if(ix>=0x3f2ca140) { /* |x|>=0.6744 */ - if(hx<0) {x = -x; y = -y;} - z = pio4-x; - w = pio4lo-y; - x = z+w; y = 0.0; - } - z = x*x; - w = z*z; - /* Break x^5*(T[1]+x^2*T[2]+...) into - * x^5(T[1]+x^4*T[3]+...+x^20*T[11]) + - * x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12])) - */ - r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11])))); - v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12]))))); - s = z*x; - r = y + z*(s*(r+v)+y); - r += T[0]*s; - w = x+r; - if(ix>=0x3f2ca140) { - v = (float)iy; - return (float)(1-((hx>>30)&2))*(v-(float)2.0*(x-(w*w/(w+v)-r))); - } - if(iy==1) return w; - else { /* if allow error up to 2 ulp, - simply return -1.0/(x+r) here */ - /* compute -1.0/(x+r) accurately */ - float a,t; - int32_t i; - z = w; - GET_FLOAT_WORD(i,z); - SET_FLOAT_WORD(z,i&0xfffff000); - v = r-(z - x); /* z+v = r+x */ - t = a = -(float)1.0/w; /* a = -1.0/w */ - GET_FLOAT_WORD(i,t); - SET_FLOAT_WORD(t,i&0xfffff000); - s = (float)1.0+t*z; - return t+a*(s+t*v); - } + float y = rb_exp(x); + return (y - 1.0f / y) * 0.5f; } - -static const int init_jk[] = {4,7,9}; /* initial value for jk */ - -static const float PIo2[] = { - 1.5703125000e+00, /* 0x3fc90000 */ - 4.5776367188e-04, /* 0x39f00000 */ - 2.5987625122e-05, /* 0x37da0000 */ - 7.5437128544e-08, /* 0x33a20000 */ - 6.0026650317e-11, /* 0x2e840000 */ - 7.3896444519e-13, /* 0x2b500000 */ - 5.3845816694e-15, /* 0x27c20000 */ - 5.6378512969e-18, /* 0x22d00000 */ - 8.3009228831e-20, /* 0x1fc40000 */ - 3.2756352257e-22, /* 0x1bc60000 */ - 6.3331015649e-25, /* 0x17440000 */ -}; - -static const float -two8 = 2.5600000000e+02, /* 0x43800000 */ -twon8 = 3.9062500000e-03; /* 0x3b800000 */ - -int kernel_rem_pio2(float *x, float *y, int e0, int nx, int prec, const int32_t *ipio2) -{ - int32_t jz,jx,jv,jp,jk,carry,n,iq[20],i,j,k,m,q0,ih; - float z,fw,f[20],fq[20],q[20]; - - /* initialize jk*/ - jk = init_jk[prec]; - jp = jk; - - /* determine jx,jv,q0, note that 3>q0 */ - jx = nx-1; - jv = (e0-3)/8; if(jv<0) jv=0; - q0 = e0-8*(jv+1); - - /* set up f[0] to f[jx+jk] where f[jx+jk] = ipio2[jv+jk] */ - j = jv-jx; m = jx+jk; - for(i=0;i<=m;i++,j++) f[i] = (j<0)? zero : (float) ipio2[j]; - - /* compute q[0],q[1],...q[jk] */ - for (i=0;i<=jk;i++) { - for(j=0,fw=0.0;j<=jx;j++) fw += x[j]*f[jx+i-j]; q[i] = fw; - } - - jz = jk; -recompute: - /* distill q[] into iq[] reversingly */ - for(i=0,j=jz,z=q[jz];j>0;i++,j--) { - fw = (float)((int32_t)(twon8* z)); - iq[i] = (int32_t)(z-two8*fw); - z = q[j-1]+fw; - } - - /* compute n */ - z = rb_scalbnf(z,q0); /* actual value of z */ - z -= (float)8.0*rb_floor(z*(float)0.125); /* trim off integer >= 8 */ - n = (int32_t) z; - z -= (float)n; - ih = 0; - if(q0>0) { /* need iq[jz-1] to determine n */ - i = (iq[jz-1]>>(8-q0)); n += i; - iq[jz-1] -= i<<(8-q0); - ih = iq[jz-1]>>(7-q0); - } - else if(q0==0) ih = iq[jz-1]>>8; - else if(z>=(float)0.5) ih=2; - - if(ih>0) { /* q > 0.5 */ - n += 1; carry = 0; - for(i=0;i0) { /* rare case: chance is 1 in 12 */ - switch(q0) { - case 1: - iq[jz-1] &= 0x7f; break; - case 2: - iq[jz-1] &= 0x3f; break; - } - } - if(ih==2) { - z = one - z; - if(carry!=0) z -= rb_scalbnf(one,q0); - } - } - - /* check if recomputation is needed */ - if(z==zero) { - j = 0; - for (i=jz-1;i>=jk;i--) j |= iq[i]; - if(j==0) { /* need recomputation */ - for(k=1;iq[jk-k]==0;k++); /* k = no. of terms needed */ - - for(i=jz+1;i<=jz+k;i++) { /* add q[jz+1] to q[jz+k] */ - f[jx+i] = (float) ipio2[jv+i]; - for(j=0,fw=0.0;j<=jx;j++) fw += x[j]*f[jx+i-j]; - q[i] = fw; - } - jz += k; - goto recompute; - } - } - - /* chop off zero terms */ - if(z==(float)0.0) { - jz -= 1; q0 -= 8; - while(iq[jz]==0) { jz--; q0-=8;} - } else { /* break z into 8-bit if necessary */ - z = rb_scalbnf(z,-q0); - if(z>=two8) { - fw = (float)((int32_t)(twon8*z)); - iq[jz] = (int32_t)(z-two8*fw); - jz += 1; q0 += 8; - iq[jz] = (int32_t) fw; - } else iq[jz] = (int32_t) z ; - } - - /* convert integer "bit" chunk to floating-point value */ - fw = rb_scalbnf(one,q0); - for(i=jz;i>=0;i--) { - q[i] = fw*(float)iq[i]; fw*=twon8; - } - - /* compute PIo2[0,...,jp]*q[jz,...,0] */ - for(i=jz;i>=0;i--) { - for(fw=0.0,k=0;k<=jp&&k<=jz-i;k++) fw += PIo2[k]*q[i+k]; - fq[jz-i] = fw; - } - - /* compress fq[] into y[] */ - switch(prec) { - case 0: - fw = 0.0; - for (i=jz;i>=0;i--) fw += fq[i]; - y[0] = (ih==0)? fw: -fw; - break; - case 1: - case 2: - fw = 0.0; - for (i=jz;i>=0;i--) fw += fq[i]; - y[0] = (ih==0)? fw: -fw; - fw = fq[0]-fw; - for (i=1;i<=jz;i++) fw += fq[i]; - y[1] = (ih==0)? fw: -fw; - break; - case 3: /* painful */ - for (i=jz;i>0;i--) { - fw = fq[i-1]+fq[i]; - fq[i] += fq[i-1]-fw; - fq[i-1] = fw; - } - for (i=jz;i>1;i--) { - fw = fq[i-1]+fq[i]; - fq[i] += fq[i-1]-fw; - fq[i-1] = fw; - } - for (fw=0.0,i=jz;i>=2;i--) fw += fq[i]; - if(ih==0) { - y[0] = fq[0]; y[1] = fq[1]; y[2] = fw; - } else { - y[0] = -fq[0]; y[1] = -fq[1]; y[2] = -fw; - } - } - return n&7; -} - - -static const int32_t two_over_pi[] = { -0xA2, 0xF9, 0x83, 0x6E, 0x4E, 0x44, 0x15, 0x29, 0xFC, -0x27, 0x57, 0xD1, 0xF5, 0x34, 0xDD, 0xC0, 0xDB, 0x62, -0x95, 0x99, 0x3C, 0x43, 0x90, 0x41, 0xFE, 0x51, 0x63, -0xAB, 0xDE, 0xBB, 0xC5, 0x61, 0xB7, 0x24, 0x6E, 0x3A, -0x42, 0x4D, 0xD2, 0xE0, 0x06, 0x49, 0x2E, 0xEA, 0x09, -0xD1, 0x92, 0x1C, 0xFE, 0x1D, 0xEB, 0x1C, 0xB1, 0x29, -0xA7, 0x3E, 0xE8, 0x82, 0x35, 0xF5, 0x2E, 0xBB, 0x44, -0x84, 0xE9, 0x9C, 0x70, 0x26, 0xB4, 0x5F, 0x7E, 0x41, -0x39, 0x91, 0xD6, 0x39, 0x83, 0x53, 0x39, 0xF4, 0x9C, -0x84, 0x5F, 0x8B, 0xBD, 0xF9, 0x28, 0x3B, 0x1F, 0xF8, -0x97, 0xFF, 0xDE, 0x05, 0x98, 0x0F, 0xEF, 0x2F, 0x11, -0x8B, 0x5A, 0x0A, 0x6D, 0x1F, 0x6D, 0x36, 0x7E, 0xCF, -0x27, 0xCB, 0x09, 0xB7, 0x4F, 0x46, 0x3F, 0x66, 0x9E, -0x5F, 0xEA, 0x2D, 0x75, 0x27, 0xBA, 0xC7, 0xEB, 0xE5, -0xF1, 0x7B, 0x3D, 0x07, 0x39, 0xF7, 0x8A, 0x52, 0x92, -0xEA, 0x6B, 0xFB, 0x5F, 0xB1, 0x1F, 0x8D, 0x5D, 0x08, -0x56, 0x03, 0x30, 0x46, 0xFC, 0x7B, 0x6B, 0xAB, 0xF0, -0xCF, 0xBC, 0x20, 0x9A, 0xF4, 0x36, 0x1D, 0xA9, 0xE3, -0x91, 0x61, 0x5E, 0xE6, 0x1B, 0x08, 0x65, 0x99, 0x85, -0x5F, 0x14, 0xA0, 0x68, 0x40, 0x8D, 0xFF, 0xD8, 0x80, -0x4D, 0x73, 0x27, 0x31, 0x06, 0x06, 0x15, 0x56, 0xCA, -0x73, 0xA8, 0xC9, 0x60, 0xE2, 0x7B, 0xC0, 0x8C, 0x6B, -}; - -static const int32_t npio2_hw[] = { -0x3fc90f00, 0x40490f00, 0x4096cb00, 0x40c90f00, 0x40fb5300, 0x4116cb00, -0x412fed00, 0x41490f00, 0x41623100, 0x417b5300, 0x418a3a00, 0x4196cb00, -0x41a35c00, 0x41afed00, 0x41bc7e00, 0x41c90f00, 0x41d5a000, 0x41e23100, -0x41eec200, 0x41fb5300, 0x4203f200, 0x420a3a00, 0x42108300, 0x4216cb00, -0x421d1400, 0x42235c00, 0x4229a500, 0x422fed00, 0x42363600, 0x423c7e00, -0x4242c700, 0x42490f00 -}; - -/* - * invpio2: 24 bits of 2/pi - * pio2_1: first 17 bit of pi/2 - * pio2_1t: pi/2 - pio2_1 - * pio2_2: second 17 bit of pi/2 - * pio2_2t: pi/2 - (pio2_1+pio2_2) - * pio2_3: third 17 bit of pi/2 - * pio2_3t: pi/2 - (pio2_1+pio2_2+pio2_3) - */ - -static const float -half = 5.0000000000e-01, /* 0x3f000000 */ -invpio2 = 6.3661980629e-01, /* 0x3f22f984 */ -pio2_1 = 1.5707855225e+00, /* 0x3fc90f80 */ -pio2_1t = 1.0804334124e-05, /* 0x37354443 */ -pio2_2 = 1.0804273188e-05, /* 0x37354400 */ -pio2_2t = 6.0770999344e-11, /* 0x2e85a308 */ -pio2_3 = 6.0770943833e-11, /* 0x2e85a300 */ -pio2_3t = 6.1232342629e-17; /* 0x248d3132 */ - -int32_t rem_pio2(float x, float *y) -{ - float z,w,t,r,fn; - float tx[3]; - int32_t e0,i,j,nx,n,ix,hx; - - GET_FLOAT_WORD(hx,x); - ix = hx&0x7fffffff; - if(ix<=0x3f490fd8) /* |x| ~<= pi/4 , no need for reduction */ - {y[0] = x; y[1] = 0; return 0;} - if(ix<0x4016cbe4) { /* |x| < 3pi/4, special case with n=+-1 */ - if(hx>0) { - z = x - pio2_1; - if((ix&0xfffffff0)!=0x3fc90fd0) { /* 24+24 bit pi OK */ - y[0] = z - pio2_1t; - y[1] = (z-y[0])-pio2_1t; - } else { /* near pi/2, use 24+24+24 bit pi */ - z -= pio2_2; - y[0] = z - pio2_2t; - y[1] = (z-y[0])-pio2_2t; - } - return 1; - } else { /* negative x */ - z = x + pio2_1; - if((ix&0xfffffff0)!=0x3fc90fd0) { /* 24+24 bit pi OK */ - y[0] = z + pio2_1t; - y[1] = (z-y[0])+pio2_1t; - } else { /* near pi/2, use 24+24+24 bit pi */ - z += pio2_2; - y[0] = z + pio2_2t; - y[1] = (z-y[0])+pio2_2t; - } - return -1; - } - } - if(ix<=0x43490f80) { /* |x| ~<= 2^7*(pi/2), medium size */ - t = rb_fabs(x); - n = (int32_t) (t*invpio2+half); - fn = (float)n; - r = t-fn*pio2_1; - w = fn*pio2_1t; /* 1st round good to 40 bit */ - if(n<32&&(int32_t)(ix&0xffffff00)!=npio2_hw[n-1]) { - y[0] = r-w; /* quick check no cancellation */ - } else { - uint32_t high; - j = ix>>23; - y[0] = r-w; - GET_FLOAT_WORD(high,y[0]); - i = j-((high>>23)&0xff); - if(i>8) { /* 2nd iteration needed, good to 57 */ - t = r; - w = fn*pio2_2; - r = t-w; - w = fn*pio2_2t-((t-r)-w); - y[0] = r-w; - GET_FLOAT_WORD(high,y[0]); - i = j-((high>>23)&0xff); - if(i>25) { /* 3rd iteration need, 74 bits acc */ - t = r; /* will cover all possible cases */ - w = fn*pio2_3; - r = t-w; - w = fn*pio2_3t-((t-r)-w); - y[0] = r-w; - } - } - } - y[1] = (r-y[0])-w; - if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;} - else return n; - } - /* - * all other (large) arguments - */ - if(ix>=0x7f800000) { /* x is inf or NaN */ - y[0]=y[1]=x-x; return 0; - } - /* set z = scalbn(|x|,ilogb(x)-7) */ - e0 = (ix>>23)-134; /* e0 = ilogb(z)-7; */ - SET_FLOAT_WORD(z, ix - ((int32_t)(e0<<23))); - for(i=0;i<2;i++) { - tx[i] = (float)((int32_t)(z)); - z = (z-tx[i])*two8; - } - tx[2] = z; - nx = 3; - while(tx[nx-1]==zero) nx--; /* skip zero term */ - n = kernel_rem_pio2(tx,y,e0,nx,2,two_over_pi); - if(hx<0) {y[0] = -y[0]; y[1] = -y[1]; return -n;} - return n; -} - +/* Tangent, simple calculus solution. */ float rb_tan(float x) { - float y[2],z=0.0; - int32_t n, ix; - - GET_FLOAT_WORD(ix,x); - - /* |x| ~< pi/4 */ - ix &= 0x7fffffff; - if(ix <= 0x3f490fda) return kernel_tan(x,z,1); - - /* tan(Inf or NaN) is NaN */ - else if (ix>=0x7f800000) return x-x; /* NaN */ - - /* argument reduction needed */ - else { - n = rem_pio2(x,y); - return kernel_tan(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even - -1 -- n odd */ - } + return rb_sin(x) / rb_cos(x); } -- cgit v1.2.3