diff options
Diffstat (limited to 'src/math/k_rem_pio2f.c')
| -rw-r--r-- | src/math/k_rem_pio2f.c | 192 |
1 files changed, 0 insertions, 192 deletions
diff --git a/src/math/k_rem_pio2f.c b/src/math/k_rem_pio2f.c deleted file mode 100644 index b543f084..00000000 --- a/src/math/k_rem_pio2f.c +++ /dev/null @@ -1,192 +0,0 @@ -/* k_rem_pio2f.c -- float version of k_rem_pio2.c - * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. - */ - -/* - * ==================================================== - * 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 <math.h> -#include "math_private.h" - -/* In the float version, the input parameter x contains 8 bit - integers, not 24 bit integers. 113 bit precision is not supported. */ - -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 -zero = 0.0, -one = 1.0, -two8 = 2.5600000000e+02, /* 0x43800000 */ -twon8 = 3.9062500000e-03; /* 0x3b800000 */ - - int __kernel_rem_pio2f(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 = scalbnf(z,q0); /* actual value of z */ - z -= (float)8.0*floorf(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]>>7; - else if(z>=(float)0.5) ih=2; - - if(ih>0) { /* q > 0.5 */ - n += 1; carry = 0; - for(i=0;i<jz ;i++) { /* compute 1-q */ - j = iq[i]; - if(carry==0) { - if(j!=0) { - carry = 1; iq[i] = 0x100- j; - } - } else iq[i] = 0xff - j; - } - if(q0>0) { /* 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 -= 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 = 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 = 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; -} |