+++ /dev/null
-/* kf_rem_pio2.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 "fdlibm.h"
-
-/* In the float version, the input parameter x contains 8 bit
- integers, not 24 bit integers. 113 bit precision is not supported. */
-
-#ifdef __STDC__
-static const int init_jk[] = {4,7,9}; /* initial value for jk */
-#else
-static int init_jk[] = {4,7,9};
-#endif
-
-#ifdef __STDC__
-static const float PIo2[] = {
-#else
-static float PIo2[] = {
-#endif
- 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 */
-};
-
-#ifdef __STDC__
-static const float
-#else
-static float
-#endif
-zero = 0.0,
-one = 1.0,
-two8 = 2.5600000000e+02, /* 0x43800000 */
-twon8 = 3.9062500000e-03; /* 0x3b800000 */
-
-#ifdef __STDC__
- int __kernel_rem_pio2f(float *x, float *y, int e0, int nx, int prec, const __int32_t *ipio2)
-#else
- int __kernel_rem_pio2f(x,y,e0,nx,prec,ipio2)
- float x[], y[]; int e0,nx,prec; __int32_t ipio2[];
-#endif
-{
- __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,(int)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]>>8;
- 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,(int)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,-(int)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,(int)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;
-}
projects / fw / altos / blobdiff