Mercurial > sdl-ios-xcode
diff src/video/e_pow.h @ 1662:782fd950bd46 SDL-1.3
Revamp of the video system in progress - adding support for multiple displays, multiple windows, and a full video mode selection API.
WARNING: None of the video drivers have been updated for the new API yet! The API is still under design and very fluid.
The code is now run through a consistent indent format:
indent -i4 -nut -nsc -br -ce
The headers are being converted to automatically generate doxygen documentation.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 28 May 2006 13:04:16 +0000 |
| parents | 7a610f25c12f |
| children | 4da1ee79c9af |
line wrap: on
line diff
--- a/src/video/e_pow.h Sun May 21 17:27:13 2006 +0000 +++ b/src/video/e_pow.h Sun May 28 13:04:16 2006 +0000 @@ -67,236 +67,275 @@ #else static double #endif -bp[] = {1.0, 1.5,}, -dp_h[] = { 0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */ -dp_l[] = { 0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */ - /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */ -L1 = 5.99999999999994648725e-01, /* 0x3FE33333, 0x33333303 */ -L2 = 4.28571428578550184252e-01, /* 0x3FDB6DB6, 0xDB6FABFF */ -L3 = 3.33333329818377432918e-01, /* 0x3FD55555, 0x518F264D */ -L4 = 2.72728123808534006489e-01, /* 0x3FD17460, 0xA91D4101 */ -L5 = 2.30660745775561754067e-01, /* 0x3FCD864A, 0x93C9DB65 */ -L6 = 2.06975017800338417784e-01, /* 0x3FCA7E28, 0x4A454EEF */ -P1 = 1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */ -P2 = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */ -P3 = 6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */ -P4 = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */ -P5 = 4.13813679705723846039e-08, /* 0x3E663769, 0x72BEA4D0 */ -lg2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */ -lg2_h = 6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */ -lg2_l = -1.90465429995776804525e-09, /* 0xBE205C61, 0x0CA86C39 */ -ovt = 8.0085662595372944372e-0017, /* -(1024-log2(ovfl+.5ulp)) */ -cp = 9.61796693925975554329e-01, /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */ -cp_h = 9.61796700954437255859e-01, /* 0x3FEEC709, 0xE0000000 =(float)cp */ -cp_l = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h*/ -ivln2 = 1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */ -ivln2_h = 1.44269502162933349609e+00, /* 0x3FF71547, 0x60000000 =24b 1/ln2*/ -ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/ + bp[] = { 1.0, 1.5, }, dp_h[] = { +0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */ + + dp_l[] = { +0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */ + + /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */ + L1 = 5.99999999999994648725e-01, /* 0x3FE33333, 0x33333303 */ + L2 = 4.28571428578550184252e-01, /* 0x3FDB6DB6, 0xDB6FABFF */ + L3 = 3.33333329818377432918e-01, /* 0x3FD55555, 0x518F264D */ + L4 = 2.72728123808534006489e-01, /* 0x3FD17460, 0xA91D4101 */ + L5 = 2.30660745775561754067e-01, /* 0x3FCD864A, 0x93C9DB65 */ + L6 = 2.06975017800338417784e-01, /* 0x3FCA7E28, 0x4A454EEF */ + P1 = 1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */ + P2 = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */ + P3 = 6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */ + P4 = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */ + P5 = 4.13813679705723846039e-08, /* 0x3E663769, 0x72BEA4D0 */ + lg2 = 6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */ + lg2_h = 6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */ + lg2_l = -1.90465429995776804525e-09, /* 0xBE205C61, 0x0CA86C39 */ + ovt = 8.0085662595372944372e-0017, /* -(1024-log2(ovfl+.5ulp)) */ + cp = 9.61796693925975554329e-01, /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */ + cp_h = 9.61796700954437255859e-01, /* 0x3FEEC709, 0xE0000000 =(float)cp */ + cp_l = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h */ + ivln2 = 1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */ + ivln2_h = 1.44269502162933349609e+00, /* 0x3FF71547, 0x60000000 =24b 1/ln2 */ + ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail */ #ifdef __STDC__ - double __ieee754_pow(double x, double y) +double +__ieee754_pow (double x, double y) #else - double __ieee754_pow(x,y) - double x, y; +double +__ieee754_pow (x, y) + double x, y; #endif { - double z,ax,z_h,z_l,p_h,p_l; - double y1,t1,t2,r,s,t,u,v,w; - int32_t i,j,k,yisint,n; - int32_t hx,hy,ix,iy; - u_int32_t lx,ly; + double z, ax, z_h, z_l, p_h, p_l; + double y1, t1, t2, r, s, t, u, v, w; + int32_t i, j, k, yisint, n; + int32_t hx, hy, ix, iy; + u_int32_t lx, ly; - EXTRACT_WORDS(hx,lx,x); - EXTRACT_WORDS(hy,ly,y); - ix = hx&0x7fffffff; iy = hy&0x7fffffff; + EXTRACT_WORDS (hx, lx, x); + EXTRACT_WORDS (hy, ly, y); + ix = hx & 0x7fffffff; + iy = hy & 0x7fffffff; /* y==zero: x**0 = 1 */ - if((iy|ly)==0) return one; + if ((iy | ly) == 0) + return one; /* +-NaN return x+y */ - if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) || - iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0))) - return x+y; + if (ix > 0x7ff00000 || ((ix == 0x7ff00000) && (lx != 0)) || + iy > 0x7ff00000 || ((iy == 0x7ff00000) && (ly != 0))) + 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 ... 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>=0x43400000) yisint = 2; /* even integer y */ - else if(iy>=0x3ff00000) { - k = (iy>>20)-0x3ff; /* exponent */ - if(k>20) { - j = ly>>(52-k); - if((u_int32_t)(j<<(52-k))==ly) yisint = 2-(j&1); - } else if(ly==0) { - j = iy>>(20-k); - if((j<<(20-k))==iy) yisint = 2-(j&1); - } - } - } + yisint = 0; + if (hx < 0) { + if (iy >= 0x43400000) + yisint = 2; /* even integer y */ + else if (iy >= 0x3ff00000) { + k = (iy >> 20) - 0x3ff; /* exponent */ + if (k > 20) { + j = ly >> (52 - k); + if ((u_int32_t) (j << (52 - k)) == ly) + yisint = 2 - (j & 1); + } else if (ly == 0) { + j = iy >> (20 - k); + if ((j << (20 - k)) == iy) + yisint = 2 - (j & 1); + } + } + } /* special value of y */ - if(ly==0) { - if (iy==0x7ff00000) { /* y is +-inf */ - if(((ix-0x3ff00000)|lx)==0) - return y - y; /* inf**+-1 is NaN */ - else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */ - return (hy>=0)? y: zero; - else /* (|x|<1)**-,+inf = inf,0 */ - return (hy<0)?-y: zero; - } - if(iy==0x3ff00000) { /* y is +-1 */ - if(hy<0) return one/x; else return x; - } - if(hy==0x40000000) return x*x; /* y is 2 */ - if(hy==0x3fe00000) { /* y is 0.5 */ - if(hx>=0) /* x >= +0 */ - return __ieee754_sqrt(x); - } - } + if (ly == 0) { + if (iy == 0x7ff00000) { /* y is +-inf */ + if (((ix - 0x3ff00000) | lx) == 0) + return y - y; /* inf**+-1 is NaN */ + else if (ix >= 0x3ff00000) /* (|x|>1)**+-inf = inf,0 */ + return (hy >= 0) ? y : zero; + else /* (|x|<1)**-,+inf = inf,0 */ + return (hy < 0) ? -y : zero; + } + if (iy == 0x3ff00000) { /* y is +-1 */ + if (hy < 0) + return one / x; + else + return x; + } + if (hy == 0x40000000) + return x * x; /* y is 2 */ + if (hy == 0x3fe00000) { /* y is 0.5 */ + if (hx >= 0) /* x >= +0 */ + return __ieee754_sqrt (x); + } + } - ax = x < 0 ? -x : x; /*fabs(x);*/ + ax = x < 0 ? -x : x; /*fabs(x); */ /* special value of x */ - if(lx==0) { - if(ix==0x7ff00000||ix==0||ix==0x3ff00000){ - z = ax; /*x is +-0,+-inf,+-1*/ - if(hy<0) z = one/z; /* z = (1/|x|) */ - if(hx<0) { - if(((ix-0x3ff00000)|yisint)==0) { - z = (z-z)/(z-z); /* (-1)**non-int is NaN */ - } else if(yisint==1) - z = -z; /* (x<0)**odd = -(|x|**odd) */ - } - return z; - } - } + if (lx == 0) { + if (ix == 0x7ff00000 || ix == 0 || ix == 0x3ff00000) { + z = ax; /*x is +-0,+-inf,+-1 */ + if (hy < 0) + z = one / z; /* z = (1/|x|) */ + if (hx < 0) { + if (((ix - 0x3ff00000) | yisint) == 0) { + z = (z - z) / (z - z); /* (-1)**non-int is NaN */ + } else if (yisint == 1) + z = -z; /* (x<0)**odd = -(|x|**odd) */ + } + return z; + } + } /* (x<0)**(non-int) is NaN */ - if(((((u_int32_t)hx>>31)-1)|yisint)==0) return (x-x)/(x-x); + if (((((u_int32_t) hx >> 31) - 1) | yisint) == 0) + return (x - x) / (x - x); /* |y| is huge */ - if(iy>0x41e00000) { /* if |y| > 2**31 */ - if(iy>0x43f00000){ /* if |y| > 2**64, must o/uflow */ - if(ix<=0x3fefffff) return (hy<0)? huge*huge:tiny*tiny; - if(ix>=0x3ff00000) return (hy>0)? huge*huge:tiny*tiny; - } - /* over/underflow if x is not close to one */ - if(ix<0x3fefffff) return (hy<0)? huge*huge:tiny*tiny; - if(ix>0x3ff00000) 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)*(0.5-t*(0.3333333333333333333333-t*0.25)); - u = ivln2_h*t; /* ivln2_h has 21 sig. bits */ - v = t*ivln2_l-w*ivln2; - t1 = u+v; - SET_LOW_WORD(t1,0); - t2 = v-(t1-u); - } else { - double s2,s_h,s_l,t_h,t_l; - n = 0; - /* take care subnormal number */ - if(ix<0x00100000) - {ax *= two53; n -= 53; GET_HIGH_WORD(ix,ax); } - n += ((ix)>>20)-0x3ff; - j = ix&0x000fffff; - /* determine interval */ - ix = j|0x3ff00000; /* normalize ix */ - if(j<=0x3988E) k=0; /* |x|<sqrt(3/2) */ - else if(j<0xBB67A) k=1; /* |x|<sqrt(3) */ - else {k=0;n+=1;ix -= 0x00100000;} - SET_HIGH_WORD(ax,ix); + if (iy > 0x41e00000) { /* if |y| > 2**31 */ + if (iy > 0x43f00000) { /* if |y| > 2**64, must o/uflow */ + if (ix <= 0x3fefffff) + return (hy < 0) ? huge * huge : tiny * tiny; + if (ix >= 0x3ff00000) + return (hy > 0) ? huge * huge : tiny * tiny; + } + /* over/underflow if x is not close to one */ + if (ix < 0x3fefffff) + return (hy < 0) ? huge * huge : tiny * tiny; + if (ix > 0x3ff00000) + 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) * (0.5 - t * (0.3333333333333333333333 - t * 0.25)); + u = ivln2_h * t; /* ivln2_h has 21 sig. bits */ + v = t * ivln2_l - w * ivln2; + t1 = u + v; + SET_LOW_WORD (t1, 0); + t2 = v - (t1 - u); + } else { + double s2, s_h, s_l, t_h, t_l; + n = 0; + /* take care subnormal number */ + if (ix < 0x00100000) { + ax *= two53; + n -= 53; + GET_HIGH_WORD (ix, ax); + } + n += ((ix) >> 20) - 0x3ff; + j = ix & 0x000fffff; + /* determine interval */ + ix = j | 0x3ff00000; /* normalize ix */ + if (j <= 0x3988E) + k = 0; /* |x|<sqrt(3/2) */ + else if (j < 0xBB67A) + k = 1; /* |x|<sqrt(3) */ + else { + k = 0; + n += 1; + ix -= 0x00100000; + } + SET_HIGH_WORD (ax, ix); - /* compute s = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */ - u = ax-bp[k]; /* bp[0]=1.0, bp[1]=1.5 */ - v = one/(ax+bp[k]); - s = u*v; - s_h = s; - SET_LOW_WORD(s_h,0); - /* t_h=ax+bp[k] High */ - t_h = zero; - SET_HIGH_WORD(t_h,((ix>>1)|0x20000000)+0x00080000+(k<<18)); - 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 = 3.0+s2+r; - SET_LOW_WORD(t_h,0); - t_l = r-((t_h-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; - SET_LOW_WORD(p_h,0); - 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 = (double)n; - t1 = (((z_h+z_l)+dp_h[k])+t); - SET_LOW_WORD(t1,0); - t2 = z_l-(((t1-t)-dp_h[k])-z_h); - } + /* compute s = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */ + u = ax - bp[k]; /* bp[0]=1.0, bp[1]=1.5 */ + v = one / (ax + bp[k]); + s = u * v; + s_h = s; + SET_LOW_WORD (s_h, 0); + /* t_h=ax+bp[k] High */ + t_h = zero; + SET_HIGH_WORD (t_h, + ((ix >> 1) | 0x20000000) + 0x00080000 + (k << 18)); + 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 = 3.0 + s2 + r; + SET_LOW_WORD (t_h, 0); + t_l = r - ((t_h - 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; + SET_LOW_WORD (p_h, 0); + 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 = (double) n; + t1 = (((z_h + z_l) + dp_h[k]) + t); + SET_LOW_WORD (t1, 0); + t2 = z_l - (((t1 - t) - dp_h[k]) - z_h); + } - s = one; /* s (sign of result -ve**odd) = -1 else = 1 */ - if(((((u_int32_t)hx>>31)-1)|(yisint-1))==0) - s = -one;/* (-ve)**(odd int) */ + s = one; /* s (sign of result -ve**odd) = -1 else = 1 */ + if (((((u_int32_t) hx >> 31) - 1) | (yisint - 1)) == 0) + s = -one; /* (-ve)**(odd int) */ /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */ - y1 = y; - SET_LOW_WORD(y1,0); - p_l = (y-y1)*t1+y*t2; - p_h = y1*t1; - z = p_l+p_h; - EXTRACT_WORDS(j,i,z); - if (j>=0x40900000) { /* z >= 1024 */ - if(((j-0x40900000)|i)!=0) /* if z > 1024 */ - return s*huge*huge; /* overflow */ - else { - if(p_l+ovt>z-p_h) return s*huge*huge; /* overflow */ - } - } else if((j&0x7fffffff)>=0x4090cc00 ) { /* z <= -1075 */ - if(((j-0xc090cc00)|i)!=0) /* z < -1075 */ - return s*tiny*tiny; /* underflow */ - else { - if(p_l<=z-p_h) return s*tiny*tiny; /* underflow */ - } - } + y1 = y; + SET_LOW_WORD (y1, 0); + p_l = (y - y1) * t1 + y * t2; + p_h = y1 * t1; + z = p_l + p_h; + EXTRACT_WORDS (j, i, z); + if (j >= 0x40900000) { /* z >= 1024 */ + if (((j - 0x40900000) | i) != 0) /* if z > 1024 */ + return s * huge * huge; /* overflow */ + else { + if (p_l + ovt > z - p_h) + return s * huge * huge; /* overflow */ + } + } else if ((j & 0x7fffffff) >= 0x4090cc00) { /* z <= -1075 */ + if (((j - 0xc090cc00) | i) != 0) /* z < -1075 */ + return s * tiny * tiny; /* underflow */ + else { + if (p_l <= z - p_h) + return s * tiny * tiny; /* underflow */ + } + } /* * compute 2**(p_h+p_l) */ - i = j&0x7fffffff; - k = (i>>20)-0x3ff; - n = 0; - if(i>0x3fe00000) { /* if |z| > 0.5, set n = [z+0.5] */ - n = j+(0x00100000>>(k+1)); - k = ((n&0x7fffffff)>>20)-0x3ff; /* new k for n */ - t = zero; - SET_HIGH_WORD(t,n&~(0x000fffff>>k)); - n = ((n&0x000fffff)|0x00100000)>>(20-k); - if(j<0) n = -n; - p_h -= t; - } - t = p_l+p_h; - SET_LOW_WORD(t,0); - 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_HIGH_WORD(j,z); - j += (n<<20); - if((j>>20)<=0) z = SDL_NAME(scalbn)(z,n); /* subnormal output */ - else SET_HIGH_WORD(z,j); - return s*z; + i = j & 0x7fffffff; + k = (i >> 20) - 0x3ff; + n = 0; + if (i > 0x3fe00000) { /* if |z| > 0.5, set n = [z+0.5] */ + n = j + (0x00100000 >> (k + 1)); + k = ((n & 0x7fffffff) >> 20) - 0x3ff; /* new k for n */ + t = zero; + SET_HIGH_WORD (t, n & ~(0x000fffff >> k)); + n = ((n & 0x000fffff) | 0x00100000) >> (20 - k); + if (j < 0) + n = -n; + p_h -= t; + } + t = p_l + p_h; + SET_LOW_WORD (t, 0); + 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_HIGH_WORD (j, z); + j += (n << 20); + if ((j >> 20) <= 0) + z = SDL_NAME (scalbn) (z, n); /* subnormal output */ + else + SET_HIGH_WORD (z, j); + return s * z; } + +/* vi: set ts=4 sw=4 expandtab: */