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Fix a bug in remquo{,f,l}, in which the quotient didn't always have the

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correct sign when the remainder was 0.

Fix a separate bug in remquo alone, in which the remainder and
quotient were both off by a bit in certain cases involving subnormal
remainders.

The bugs affected all platforms except amd64 and i386, on which the
routines are implemented in assembly.

PR:		166463
Submitted by:	Ilya Burylov
MFC after:	2 weeks
This commit is contained in:
David Schultz 2012-04-07 03:59:12 +00:00
parent 045bc7882e
commit 1cbd288942
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=233973
3 changed files with 8 additions and 5 deletions
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7
lib/msun/src/s_remquo.c
View File

@ -51,7 +51,7 @@ remquo(double x, double y, int *quo)
goto fixup; /* |x|<|y| return x or x-y */
}
if(lx==ly) {
*quo = 1;
*quo = (sxy ? -1 : 1);
return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/
}
}
@ -114,6 +114,7 @@ remquo(double x, double y, int *quo)
/* convert back to floating value and restore the sign */
if((hx|lx)==0) { /* return sign(x)*0 */
q &= 0x7fffffff;
*quo = (sxy ? -q : q);
return Zero[(u_int32_t)sx>>31];
}
@ -129,9 +130,9 @@ remquo(double x, double y, int *quo)
lx = (lx>>n)|((u_int32_t)hx<<(32-n));
hx >>= n;
} else if (n<=31) {
lx = (hx<<(32-n))|(lx>>n); hx = sx;
lx = (hx<<(32-n))|(lx>>n); hx = 0;
} else {
lx = hx>>(n-32); hx = sx;
lx = hx>>(n-32); hx = 0;
}
}
fixup:

3
lib/msun/src/s_remquof.c
View File

@ -46,7 +46,7 @@ remquof(float x, float y, int *quo)
q = 0;
goto fixup; /* |x|<|y| return x or x-y */
} else if(hx==hy) {
*quo = 1;
*quo = (sxy ? -1 : 1);
return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/
}
@ -88,6 +88,7 @@ remquof(float x, float y, int *quo)
/* convert back to floating value and restore the sign */
if(hx==0) { /* return sign(x)*0 */
q &= 0x7fffffff;
*quo = (sxy ? -q : q);
return Zero[(u_int32_t)sx>>31];
}

3
lib/msun/src/s_remquol.c
View File

@ -96,7 +96,7 @@ remquol(long double x, long double y, int *quo)
goto fixup; /* |x|<|y| return x or x-y */
}
if(ux.bits.manh==uy.bits.manh && ux.bits.manl==uy.bits.manl) {
*quo = 1;
*quo = (sxy ? -1 : 1);
return Zero[sx]; /* |x|=|y| return x*0*/
}
}
@ -138,6 +138,7 @@ remquol(long double x, long double y, int *quo)
/* convert back to floating value and restore the sign */
if((hx|lx)==0) { /* return sign(x)*0 */
q &= 0x7fffffff;
*quo = (sxy ? -q : q);
return Zero[sx];
}