diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/mpatan.c | 107 |
1 files changed, 61 insertions, 46 deletions
diff --git a/sysdeps/ieee754/dbl-64/mpatan.c b/sysdeps/ieee754/dbl-64/mpatan.c index 0f5a24a3c7..cc879d8ec4 100644 --- a/sysdeps/ieee754/dbl-64/mpatan.c +++ b/sysdeps/ieee754/dbl-64/mpatan.c @@ -39,63 +39,78 @@ #include "mpatan.h" -void __mpsqrt(mp_no *, mp_no *, int); - void SECTION -__mpatan(mp_no *x, mp_no *y, int p) { +__mpatan (mp_no *x, mp_no *y, int p) +{ - int i,m,n; + int i, m, n; double dx; - mp_no - mptwoim1 = {0,{0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0, - 0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0, - 0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0}}; + mp_no mptwoim1 = + { + 0, + { + 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, + 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, + 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 + } + }; - mp_no mps,mpsm,mpt,mpt1,mpt2,mpt3; + mp_no mps, mpsm, mpt, mpt1, mpt2, mpt3; - /* Choose m and initiate mptwoim1 */ - if (EX>0) m=7; - else if (EX<0) m=0; - else { - __mp_dbl(x,&dx,p); dx=ABS(dx); - for (m=6; m>0; m--) - {if (dx>__atan_xm[m].d) break;} + /* Choose m and initiate mptwoim1. */ + if (EX > 0) + m = 7; + else if (EX < 0) + m = 0; + else + { + __mp_dbl (x, &dx, p); + dx = ABS (dx); + for (m = 6; m > 0; m--) + { + if (dx > __atan_xm[m].d) + break; + } } - mptwoim1.e = 1; - mptwoim1.d[0] = ONE; + mptwoim1.e = 1; + mptwoim1.d[0] = ONE; - /* Reduce x m times */ - __sqr(x,&mpsm,p); - if (m==0) __cpy(x,&mps,p); - else { - for (i=0; i<m; i++) { - __add(&mpone,&mpsm,&mpt1,p); - __mpsqrt(&mpt1,&mpt2,p); - __add(&mpt2,&mpt2,&mpt1,p); - __add(&mptwo,&mpsm,&mpt2,p); - __add(&mpt1,&mpt2,&mpt3,p); - __dvd(&mpsm,&mpt3,&mpt1,p); - __cpy(&mpt1,&mpsm,p); - } - __mpsqrt(&mpsm,&mps,p); mps.d[0] = X[0]; + /* Reduce x m times. */ + __sqr (x, &mpsm, p); + if (m == 0) + __cpy (x, &mps, p); + else + { + for (i = 0; i < m; i++) + { + __add (&mpone, &mpsm, &mpt1, p); + __mpsqrt (&mpt1, &mpt2, p); + __add (&mpt2, &mpt2, &mpt1, p); + __add (&mptwo, &mpsm, &mpt2, p); + __add (&mpt1, &mpt2, &mpt3, p); + __dvd (&mpsm, &mpt3, &mpt1, p); + __cpy (&mpt1, &mpsm, p); + } + __mpsqrt (&mpsm, &mps, p); + mps.d[0] = X[0]; } - /* Evaluate a truncated power series for Atan(s) */ - n=__atan_np[p]; mptwoim1.d[1] = __atan_twonm1[p].d; - __dvd(&mpsm,&mptwoim1,&mpt,p); - for (i=n-1; i>1; i--) { + /* Evaluate a truncated power series for Atan(s). */ + n = __atan_np[p]; + mptwoim1.d[1] = __atan_twonm1[p].d; + __dvd (&mpsm, &mptwoim1, &mpt, p); + for (i = n - 1; i > 1; i--) + { mptwoim1.d[1] -= TWO; - __dvd(&mpsm,&mptwoim1,&mpt1,p); - __mul(&mpsm,&mpt,&mpt2,p); - __sub(&mpt1,&mpt2,&mpt,p); + __dvd (&mpsm, &mptwoim1, &mpt1, p); + __mul (&mpsm, &mpt, &mpt2, p); + __sub (&mpt1, &mpt2, &mpt, p); } - __mul(&mps,&mpt,&mpt1,p); - __sub(&mps,&mpt1,&mpt,p); - - /* Compute Atan(x) */ - mptwoim1.d[1] = 1 << m; - __mul(&mptwoim1,&mpt,y,p); + __mul (&mps, &mpt, &mpt1, p); + __sub (&mps, &mpt1, &mpt, p); - return; + /* Compute Atan(x). */ + mptwoim1.d[1] = 1 << m; + __mul (&mptwoim1, &mpt, y, p); } |