svn commit: r345829 - head/sys/powerpc/fpu
Justin Hibbits
jhibbits at FreeBSD.org
Tue Sep 3 14:06:29 UTC 2019
Author: jhibbits
Date: Wed Apr 3 03:54:30 2019
New Revision: 345829
URL: https://svnweb.freebsd.org/changeset/base/345829
Log:
powerpc: Apply r178139 from sparc64 to powerpc's fpu_sqrt
This fix was committed less than 2 months after the code was forked into the
powerpc kernel. Though powerpc doesn't use quad-precision floating point,
or need it for emulation, the changes do look like correctness fixes
overall.
This was found while trying to get fsqrt emulation working on e5500, which
does have a real FPU, but lacks the fsqrt instruction. This is not the
complete fix, the rest is to be committed separately.
MFC after: 1 week
Modified:
head/sys/powerpc/fpu/fpu_sqrt.c
Modified: head/sys/powerpc/fpu/fpu_sqrt.c
==============================================================================
--- head/sys/powerpc/fpu/fpu_sqrt.c Wed Apr 3 03:50:16 2019 (r345828)
+++ head/sys/powerpc/fpu/fpu_sqrt.c Wed Apr 3 03:54:30 2019 (r345829)
@@ -353,7 +353,7 @@ fpu_sqrt(struct fpemu *fe)
FPU_SUBC(d0, x0, t0);
if ((int)d0 >= 0) {
x0 = d0, x1 = d1, x2 = d2;
- q |= bit;
+ q = bit;
y1 |= 1; /* now t1, y1 are set in concrete */
}
ODD_DOUBLE;
@@ -385,12 +385,12 @@ fpu_sqrt(struct fpemu *fe)
FPU_SUBCS(d2, x2, t2);
FPU_SUBCS(d1, x1, t1);
FPU_SUBC(d0, x0, t0);
- ODD_DOUBLE;
if ((int)d0 >= 0) {
- x0 = d0, x1 = d1, x2 = d2;
- q |= bit;
+ x0 = d0, x1 = d1, x2 = d2; x3 = d3;
+ q = bit;
y2 |= 1;
}
+ ODD_DOUBLE;
while ((bit >>= 1) != 0) {
EVEN_DOUBLE;
t3 = y3 | bit;
@@ -399,7 +399,7 @@ fpu_sqrt(struct fpemu *fe)
FPU_SUBCS(d1, x1, t1);
FPU_SUBC(d0, x0, t0);
if ((int)d0 >= 0) {
- x0 = d0, x1 = d1, x2 = d2;
+ x0 = d0, x1 = d1, x2 = d2; x3 = d3;
q |= bit;
y3 |= bit << 1;
}
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