target/i386: check for empty register in FXAM
commit93c3593ad04f2610fd0a176dfa89a7e40b6afe1f
authorPaolo Bonzini <pbonzini@redhat.com>
Fri, 21 Feb 2020 16:20:17 +0000 (21 17:20 +0100)
committerPaolo Bonzini <pbonzini@redhat.com>
Tue, 25 Feb 2020 08:18:01 +0000 (25 09:18 +0100)
treeec2a66d9b003ce146f45e20bdccdd5d8985d8d0e
parentcce8944cc9efab47d4bf29cfffb3470371c3541b
target/i386: check for empty register in FXAM

The fxam instruction returns the wrong result after fdecstp or after
an underflow.  Check fptags to handle this.

Reported-by: <chengang@emindsoft.com.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
target/i386/fpu_helper.c