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Fix missing sign for overflow/underflow where x is negative and y is large odd integer

This commit is contained in:
Andoni Arregi 2023-04-12 17:34:42 +02:00 committed by Jeff Johnston
parent be2749cd4e
commit 5a961061de
1 changed files with 18 additions and 19 deletions
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35
newlib/libm/math/e_pow.c
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@ -107,7 +107,7 @@ ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
#endif
{
double z,ax,z_h,z_l,p_h,p_l;
double y1,t1,t2,r,s,t,u,v,w;
double y1,t1,t2,r,s,sign,t,u,v,w;
__int32_t i,j,k,yisint,n;
__int32_t hx,hy,ix,iy;
__uint32_t lx,ly;
@ -186,21 +186,24 @@ ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
}
/* (x<0)**(non-int) is NaN */
/* REDHAT LOCAL: This used to be
if((((hx>>31)+1)|yisint)==0) return (x-x)/(x-x);
but ANSI C says a right shift of a signed negative quantity is
implementation defined. */
if(((((__uint32_t)hx>>31)-1)|yisint)==0) return (x-x)/(x-x);
n = ((uint32_t)hx >> 31U) - 1U;
if ((n | yisint) == 0) return (x-x)/(x-x);
sign = one; /* (sign of result -ve**odd) = -1 else = 1 */
if ((n | (yisint - 1)) == 0) {
sign = -one; /* (-ve)**(odd int) */
}
/* |y| is huge */
if(iy>0x41e00000) { /* if |y| > 2**31 */
if(iy>0x43f00000){ /* if |y| > 2**64, must o/uflow */
if(iy>0x43f00000){ /* if |y| > 2**64, must o/uflow and y is an even integer */
if(ix<=0x3fefffff) return (hy<0)? __math_oflow(0):__math_uflow(0);
if(ix>=0x3ff00000) return (hy>0)? __math_oflow(0):__math_uflow(0);
}
/* over/underflow if x is not close to one */
if(ix<0x3fefffff) return (hy<0)? __math_oflow(0):__math_uflow(0);
if(ix>0x3ff00000) return (hy>0)? __math_oflow(0):__math_uflow(0);
if(ix<0x3fefffff) return (hy<0)? __math_oflow(sign<0):__math_uflow(sign<0);
if(ix>0x3ff00000) return (hy>0)? __math_oflow(sign<0):__math_uflow(sign<0);
/* now |1-x| is tiny <= 2**-20, suffice to compute
log(x) by x-x^2/2+x^3/3-x^4/4 */
t = ax-1; /* t has 20 trailing zeros */
@ -260,10 +263,6 @@ ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
t2 = z_l-(((t1-t)-dp_h[k])-z_h);
}
s = one; /* s (sign of result -ve**odd) = -1 else = 1 */
if(((((__uint32_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 = y;
SET_LOW_WORD(y1,0);
@ -273,15 +272,15 @@ ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
EXTRACT_WORDS(j,i,z);
if (j>=0x40900000) { /* z >= 1024 */
if(((j-0x40900000)|i)!=0) /* if z > 1024 */
return __math_oflow(s<0); /* overflow */
return __math_oflow(sign<0); /* overflow */
else {
if(p_l+ovt>z-p_h) return __math_oflow(s<0); /* overflow */
if(p_l+ovt>z-p_h) return __math_oflow(sign<0); /* overflow */
}
} else if((j&0x7fffffff)>=0x4090cc00 ) { /* z <= -1075 */
if(((j-0xc090cc00)|i)!=0) /* z < -1075 */
return __math_uflow(s<0); /* underflow */
return __math_uflow(sign<0); /* underflow */
else {
if(p_l<=z-p_h) return __math_uflow(s<0); /* underflow */
if(p_l<=z-p_h) return __math_uflow(sign<0); /* underflow */
}
}
/*
@ -313,7 +312,7 @@ ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
j += (n<<20);
if((j>>20)<=0) z = scalbn(z,(int)n); /* subnormal output */
else SET_HIGH_WORD(z,j);
return s*z;
return sign*z;
}
#endif /* defined(_DOUBLE_IS_32BITS) */