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author | Rich Felker <dalias@aerifal.cx> | 2012-03-13 01:17:53 -0400 |
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committer | Rich Felker <dalias@aerifal.cx> | 2012-03-13 01:17:53 -0400 |
commit | b69f695acedd4ce2798ef9ea28d834ceccc789bd (patch) | |
tree | eafd98b9b75160210f3295ac074d699f863d958e /src/math/k_rem_pio2f.c | |
parent | d46cf2e14cc4df7cc75e77d7009fcb6df1f48a33 (diff) | |
download | musl-b69f695acedd4ce2798ef9ea28d834ceccc789bd.tar.gz musl-b69f695acedd4ce2798ef9ea28d834ceccc789bd.tar.bz2 musl-b69f695acedd4ce2798ef9ea28d834ceccc789bd.tar.xz musl-b69f695acedd4ce2798ef9ea28d834ceccc789bd.zip |
first commit of the new libm!
thanks to the hard work of Szabolcs Nagy (nsz), identifying the best
(from correctness and license standpoint) implementations from freebsd
and openbsd and cleaning them up! musl should now fully support c99
float and long double math functions, and has near-complete complex
math support. tgmath should also work (fully on gcc-compatible
compilers, and mostly on any c99 compiler).
based largely on commit 0376d44a890fea261506f1fc63833e7a686dca19 from
nsz's libm git repo, with some additions (dummy versions of a few
missing long double complex functions, etc.) by me.
various cleanups still need to be made, including re-adding (if
they're correct) some asm functions that were dropped.
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; -} |