On Sun, Mar 31, 2013 at 04:19:45PM -0700, Richard Henderson wrote: > On 2013-03-30 16:54, Aurelien Jarno wrote: > >The overflow computation of nego and subf*o instructions has been broken > >in commit ffe30937. This patch fixes it. > > > >With this change the PPC emulation passes the Gwenole Beauchesne > >testsuite again. > > > >Cc: Alexander Graf <ag...@suse.de> > >Cc: Richard Henderson <r...@twiddle.net> > >Signed-off-by: Aurelien Jarno <aurel...@aurel32.net> > >--- > > target-ppc/translate.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > >diff --git a/target-ppc/translate.c b/target-ppc/translate.c > >index 5e741d1..062493a 100644 > >--- a/target-ppc/translate.c > >+++ b/target-ppc/translate.c > >@@ -749,7 +749,7 @@ static inline void gen_op_arith_compute_ov(DisasContext > >*ctx, TCGv arg0, > > tcg_gen_xor_tl(cpu_ov, arg0, arg1); > > tcg_gen_xor_tl(t0, arg1, arg2); > > if (sub) { > >- tcg_gen_and_tl(cpu_ov, cpu_ov, t0); > >+ tcg_gen_andc_tl(cpu_ov, t0, cpu_ov); > > } else { > > tcg_gen_andc_tl(cpu_ov, cpu_ov, t0); > > } > > I'm a bit confused. This is the exact same algorithm that's used on > ARM and i386. And as far as I can determine, all three platforms > have the same definition of "overflow". >
I based my patch on the previous version of the code, which swaps *both* the brcond conditions testing the results of the xor. As far I understand the brcond are replaced by the and/andc in your patch. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel32.net