On 06/25/2017 03:19 PM, Aurelien Jarno wrote:
On 2017-06-23 01:12, David Hildenbrand wrote:If we have for example: r3 contains 0x00000000ffffffff ec 33 3f bf 61 55 risbg %r3,%r3,63,191,97We want to rotate 33 to the left and only keep MSB bit 63 of that. So the result is then exactly 1 (we're reading the sign of the 32 bit value). Current code assumes that we can do that via an extract, which is not true (at least not that easy) and produces a 0.I think the mistake there is that the rotation is done to the left, while in extract the "shift" is done to the right. The following patch should be enough: --- a/target/s390x/translate.c +++ b/target/s390x/translate.c @@ -3441,8 +3441,8 @@ static ExitStatus op_risbg(DisasContext *s, DisasOps *o) }/* In some cases we can implement this with extract. */- if (imask == 0 && pos == 0 && len > 0 && rot + len <= 64) { - tcg_gen_extract_i64(o->out, o->in2, rot, len); + if (imask == 0 && pos == 0 && len > 0 && rot - len >= 0) { + tcg_gen_extract_i64(o->out, o->in2, 64 - rot, len); return NO_EXIT;
Agreed. Included. r~
