diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | sysdeps/ieee754/ldbl-128ibm/e_powl.c | 34 |
2 files changed, 23 insertions, 17 deletions
diff --git a/ChangeLog b/ChangeLog index 32fae2de24..ec2b50820a 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,11 @@ 2016-02-19 Joseph Myers <joseph@codesourcery.com> + [BZ #19674] + * sysdeps/ieee754/ldbl-128ibm/e_powl.c (__ieee754_powl): Include + sign in overflowing and underflowing results when overflow or + underflow is detected early. Include sign in result before rather + than after scaling. + [BZ #19603] * sysdeps/ieee754/ldbl-128ibm/e_remainderl.c (__ieee754_remainderl): Adjust sign of integer version of low part diff --git a/sysdeps/ieee754/ldbl-128ibm/e_powl.c b/sysdeps/ieee754/ldbl-128ibm/e_powl.c index 90340e890e..861b44ac8b 100644 --- a/sysdeps/ieee754/ldbl-128ibm/e_powl.c +++ b/sysdeps/ieee754/ldbl-128ibm/e_powl.c @@ -148,7 +148,7 @@ long double __ieee754_powl (long double x, long double y) { long double z, ax, z_h, z_l, p_h, p_l; - long double y1, t1, t2, r, s, t, u, v, w; + long double y1, t1, t2, r, s, sgn, t, u, v, w; long double s2, s_h, s_l, t_h, t_l, ay; int32_t i, j, k, yisint, n; uint32_t ix, iy; @@ -263,6 +263,11 @@ __ieee754_powl (long double x, long double y) if (((((u_int32_t) hx >> 31) - 1) | yisint) == 0) return (x - x) / (x - x); + /* sgn (sign of result -ve**odd) = -1 else = 1 */ + sgn = one; + if (((((u_int32_t) hx >> 31) - 1) | (yisint - 1)) == 0) + sgn = -one; /* (-ve)**(odd int) */ + /* |y| is huge. 2^-16495 = 1/2 of smallest representable value. If (1 - 1/131072)^y underflows, y > 1.4986e9 */ @@ -272,15 +277,15 @@ __ieee754_powl (long double x, long double y) if (iy > 0x47d654b0) { if (ix <= 0x3fefffff) - return (hy < 0) ? huge * huge : tiny * tiny; + return (hy < 0) ? sgn * huge * huge : sgn * tiny * tiny; if (ix >= 0x3ff00000) - return (hy > 0) ? huge * huge : tiny * tiny; + return (hy > 0) ? sgn * huge * huge : sgn * tiny * tiny; } /* over/underflow if x is not close to one */ if (ix < 0x3fefffff) - return (hy < 0) ? huge * huge : tiny * tiny; + return (hy < 0) ? sgn * huge * huge : sgn * tiny * tiny; if (ix > 0x3ff00000) - return (hy > 0) ? huge * huge : tiny * tiny; + return (hy > 0) ? sgn * huge * huge : sgn * tiny * tiny; } ay = y > 0 ? y : -y; @@ -351,11 +356,6 @@ __ieee754_powl (long double x, long double y) t1 = ldbl_high (t1); t2 = z_l - (((t1 - t) - dp_h[k]) - z_h); - /* s (sign of result -ve**odd) = -1 else = 1 */ - s = one; - if (((((u_int32_t) hx >> 31) - 1) | (yisint - 1)) == 0) - s = -one; /* (-ve)**(odd int) */ - /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */ y1 = ldbl_high (y); p_l = (y - y1) * t1 + y * t2; @@ -367,22 +367,22 @@ __ieee754_powl (long double x, long double y) { /* if z > 16384 */ if (((j - 0x40d00000) | lj) != 0) - return s * huge * huge; /* overflow */ + return sgn * huge * huge; /* overflow */ else { if (p_l + ovt > z - p_h) - return s * huge * huge; /* overflow */ + return sgn * huge * huge; /* overflow */ } } else if ((j & 0x7fffffff) >= 0x40d01b90) /* z <= -16495 */ { /* z < -16495 */ if (((j - 0xc0d01bc0) | lj) != 0) - return s * tiny * tiny; /* underflow */ + return sgn * tiny * tiny; /* underflow */ else { if (p_l <= z - p_h) - return s * tiny * tiny; /* underflow */ + return sgn * tiny * tiny; /* underflow */ } } /* compute 2**(p_h+p_l) */ @@ -408,8 +408,8 @@ __ieee754_powl (long double x, long double y) t1 = z - t * u / v; r = (z * t1) / (t1 - two) - (w + z * w); z = one - (r - z); - z = __scalbnl (z, n); - math_check_force_underflow_nonneg (z); - return s * z; + z = __scalbnl (sgn * z, n); + math_check_force_underflow (z); + return z; } strong_alias (__ieee754_powl, __powl_finite) |