S390: Fix Div64 sequence + DLGR simulation

src/s390/simulator-s390.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdarg.h>
 #include <stdlib.h>
 #include <cmath>
 
 #if V8_TARGET_ARCH_S390
 
@@ skipping 2702 matching lines @@
       int32_t low_bits = product & 0x00000000FFFFFFFF;
       set_low_register(r1, high_bits);
       set_low_register(r1 + 1, low_bits);
       break;
     }
     case DLGR: {
 #ifdef V8_TARGET_ARCH_S390X
       RREInstruction* rreinst = reinterpret_cast<RREInstruction*>(instr);
       int r1 = rreinst->R1Value();
       int r2 = rreinst->R2Value();
-      uint64_t r1_val = static_cast<uint64_t>(r1);
-      uint64_t r2_val = static_cast<uint64_t>(r2);
+      uint64_t r1_val = get_register(r1);
+      uint64_t r2_val = get_register(r2);
       DCHECK(r1 % 2 == 0);
       unsigned __int128 dividend = static_cast<unsigned __int128>(r1_val) << 64;
-      dividend += static_cast<uint64_t>(r1 + 1);
+      dividend += get_register(r1 + 1);
       uint64_t remainder = dividend % r2_val;
       uint64_t quotient = dividend / r2_val;
       r1_val = remainder;
       set_register(r1, remainder);
       set_register(r1 + 1, quotient);
 #else
       UNREACHABLE();
 #endif
       break;
     }
@@ skipping 2301 matching lines @@
   uintptr_t address = *stack_slot;
   set_register(sp, current_sp + sizeof(uintptr_t));
   return address;
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // USE_SIMULATOR
 #endif  // V8_TARGET_ARCH_S390