diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/mpa.h')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/mpa.h | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/mpa.h b/sysdeps/ieee754/dbl-64/mpa.h index debb3b2a96..06343d46d1 100644 --- a/sysdeps/ieee754/dbl-64/mpa.h +++ b/sysdeps/ieee754/dbl-64/mpa.h @@ -123,3 +123,33 @@ extern void __mpsqrt (mp_no *, mp_no *, int); extern void __mpexp (mp_no *, mp_no *, int); extern void __c32 (mp_no *, mp_no *, mp_no *, int); extern int __mpranred (double, mp_no *, int); + +/* Given a power POW, build a multiprecision number 2^POW. */ +static inline void +__pow_mp (int pow, mp_no *y, int p) +{ + int i, rem; + + /* The exponent is E such that E is a factor of 2^24. The remainder (of the + form 2^x) goes entirely into the first digit of the mantissa as it is + always less than 2^24. */ + EY = pow / 24; + rem = pow - EY * 24; + EY++; + + /* If the remainder is negative, it means that POW was negative since + |EY * 24| <= |pow|. Adjust so that REM is positive and still less than + 24 because of which, the mantissa digit is less than 2^24. */ + if (rem < 0) + { + EY--; + rem += 24; + } + /* The sign of any 2^x is always positive. */ + Y[0] = ONE; + Y[1] = 1 << rem; + + /* Everything else is ZERO. */ + for (i = 2; i <= p; i++) + Y[i] = ZERO; +} |