[PATCH v3 5/5] s390x/tcg: Ignore register content if b1/b2 is zero when handling EXECUTE

[David Hildenbrand <david@redhat.com>]

In our EXECUTE fast path, we have to ignore the content of r0, if
specified by b1 or b2.

Fixes: d376f123c7de ("target/s390x: Re-implement a few EXECUTE target insns directly")
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/mem_helper.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
index 0108611cc9..1901e9dfc7 100644
--- a/target/s390x/mem_helper.c
+++ b/target/s390x/mem_helper.c
@@ -2473,8 +2473,8 @@ void HELPER(ex)(CPUS390XState *env, uint32_t ilen, uint64_t r1, uint64_t addr)
             uint32_t d1 = extract64(insn, 32, 12);
             uint32_t b2 = extract64(insn, 28, 4);
             uint32_t d2 = extract64(insn, 16, 12);
-            uint64_t a1 = wrap_address(env, env->regs[b1] + d1);
-            uint64_t a2 = wrap_address(env, env->regs[b2] + d2);
+            uint64_t a1 = wrap_address(env, (b1 ? env->regs[b1] : 0) + d1);
+            uint64_t a2 = wrap_address(env, (b2 ? env->regs[b2] : 0) + d2);
 
             env->cc_op = helper(env, l, a1, a2, 0);
             env->psw.addr += ilen;
-- 
2.29.2