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Format mpsqrt.c

This commit is contained in:
Siddhesh Poyarekar 2013-02-27 11:28:20 +05:30
parent a688864eed
commit 09c14ed23e
2 changed files with 46 additions and 34 deletions
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2
ChangeLog
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@ -1,5 +1,7 @@
2013-02-27 Siddhesh Poyarekar <siddhesh@redhat.com>
* sysdeps/ieee754/dbl-64/mpsqrt.c: Reformat.
* sysdeps/ieee754/dbl-64/mpatan2.c: Reformat.
* sysdeps/ieee754/dbl-64/mpatan.c: Reformat.

78
sysdeps/ieee754/dbl-64/mpsqrt.c
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@ -45,33 +45,37 @@
/* p as integer. Routine computes sqrt(*x) and stores result in *y */
/****************************************************************************/
static double fastiroot(double);
static double fastiroot (double);
void
SECTION
__mpsqrt(mp_no *x, mp_no *y, int p) {
int i,m,ey;
double dx,dy;
static const mp_no
mphalf = {0,{1.0,8388608.0 /* 2^23 */}},
mp3halfs = {1,{1.0,1.0,8388608.0 /* 2^23 */}};
mp_no mpxn,mpz,mpu,mpt1,mpt2;
__mpsqrt (mp_no *x, mp_no *y, int p)
{
int i, m, ey;
double dx, dy;
static const mp_no mphalf = {0, {1.0, 8388608.0 /* 2^23 */}};
static const mp_no mp3halfs = {1, {1.0, 1.0, 8388608.0 /* 2^23 */}};
mp_no mpxn, mpz, mpu, mpt1, mpt2;
ey=EX/2; __cpy(x,&mpxn,p); mpxn.e -= (ey+ey);
__mp_dbl(&mpxn,&dx,p); dy=fastiroot(dx); __dbl_mp(dy,&mpu,p);
__mul(&mpxn,&mphalf,&mpz,p);
ey = EX / 2;
__cpy (x, &mpxn, p);
mpxn.e -= (ey + ey);
__mp_dbl (&mpxn, &dx, p);
dy = fastiroot (dx);
__dbl_mp (dy, &mpu, p);
__mul (&mpxn, &mphalf, &mpz, p);
m=__mpsqrt_mp[p];
for (i=0; i<m; i++) {
__sqr(&mpu,&mpt1,p);
__mul(&mpt1,&mpz,&mpt2,p);
__sub(&mp3halfs,&mpt2,&mpt1,p);
__mul(&mpu,&mpt1,&mpt2,p);
__cpy(&mpt2,&mpu,p);
}
__mul(&mpxn,&mpu,y,p); EY += ey;
return;
m = __mpsqrt_mp[p];
for (i = 0; i < m; i++)
{
__sqr (&mpu, &mpt1, p);
__mul (&mpt1, &mpz, &mpt2, p);
__sub (&mp3halfs, &mpt2, &mpt1, p);
__mul (&mpu, &mpt1, &mpt2, p);
__cpy (&mpt2, &mpu, p);
}
__mul (&mpxn, &mpu, y, p);
EY += ey;
}
/***********************************************************/
@ -80,22 +84,28 @@ __mpsqrt(mp_no *x, mp_no *y, int p) {
/***********************************************************/
static double
SECTION
fastiroot(double x) {
union {int i[2]; double d;} p,q;
double y,z, t;
fastiroot (double x)
{
union
{
int i[2];
double d;
} p, q;
double y, z, t;
int n;
static const double c0 = 0.99674, c1 = -0.53380, c2 = 0.45472, c3 = -0.21553;
static const double c0 = 0.99674, c1 = -0.53380;
static const double c2 = 0.45472, c3 = -0.21553;
p.d = x;
p.i[HIGH_HALF] = (p.i[HIGH_HALF] & 0x3FFFFFFF ) | 0x3FE00000 ;
p.i[HIGH_HALF] = (p.i[HIGH_HALF] & 0x3FFFFFFF) | 0x3FE00000;
q.d = x;
y = p.d;
z = y -1.0;
n = (q.i[HIGH_HALF] - p.i[HIGH_HALF])>>1;
z = ((c3*z + c2)*z + c1)*z + c0; /* 2**-7 */
z = z*(1.5 - 0.5*y*z*z); /* 2**-14 */
p.d = z*(1.5 - 0.5*y*z*z); /* 2**-28 */
z = y - 1.0;
n = (q.i[HIGH_HALF] - p.i[HIGH_HALF]) >> 1;
z = ((c3 * z + c2) * z + c1) * z + c0; /* 2**-7 */
z = z * (1.5 - 0.5 * y * z * z); /* 2**-14 */
p.d = z * (1.5 - 0.5 * y * z * z); /* 2**-28 */
p.i[HIGH_HALF] -= n;
t = x*p.d;
return p.d*(1.5 - 0.5*p.d*t);
t = x * p.d;
return p.d * (1.5 - 0.5 * p.d * t);
}