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[PATCH] target/s390x/translate: Fix RNSBG instruction

From: Thomas Huth
Subject: [PATCH] target/s390x/translate: Fix RNSBG instruction
Date: Thu, 30 Jan 2020 14:34:17 +0100

RNSBG is handled via the op_rosbg() helper function. But RNSBG has
the opcode 0xEC54, i.e. 0x54 as second byte, while op_rosbg() currently
checks for 0x55. This seems to be a typo, fix it to use 0x54 instead,
so that op_rosbg() does not abort() anymore if a program uses RNSBG.

I've checked with a simply test function that I now get the same results
with KVM and with TCG:

 static void test_rnsbg(void)
        uint64_t r1, r2;

        r2 = 0xffff000000000000UL;
        r1 = 0x123456789bdfaaaaUL;
        asm volatile (" rnsbg %0,%1,12,61,16 " : "+r"(r1) : "r"(r2));

        printf("r1 afterwards: 0x%lx\n", r1);

Buglink: https://bugs.launchpad.net/qemu/+bug/1860920
Signed-off-by: Thomas Huth <address@hidden>
 target/s390x/translate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/s390x/translate.c b/target/s390x/translate.c
index 0bd2073718..4f6f1e31cd 100644
--- a/target/s390x/translate.c
+++ b/target/s390x/translate.c
@@ -3874,7 +3874,7 @@ static DisasJumpType op_rosbg(DisasContext *s, DisasOps 
     /* Operate.  */
     switch (s->fields.op2) {
-    case 0x55: /* AND */
+    case 0x54: /* AND */
         tcg_gen_ori_i64(o->in2, o->in2, ~mask);
         tcg_gen_and_i64(o->out, o->out, o->in2);

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