s390: optimize for compares

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 1830 matching lines @@
 }
 
 /**
  * Reads a double value from memory at given address.
  */
 double Simulator::ReadDouble(intptr_t addr) {
   double* ptr = reinterpret_cast<double*>(addr);
   return *ptr;
 }
 
+float Simulator::ReadFloat(intptr_t addr) {
+  float* ptr = reinterpret_cast<float*>(addr);
+  return *ptr;
+}
+
 // Returns the limit of the stack area to enable checking for stack overflows.
 uintptr_t Simulator::StackLimit(uintptr_t c_limit) const {
   // The simulator uses a separate JS stack. If we have exhausted the C stack,
   // we also drop down the JS limit to reflect the exhaustion on the JS stack.
   if (GetCurrentStackPosition() < c_limit) {
     return reinterpret_cast<uintptr_t>(get_sp());
   }
 
   // Otherwise the limit is the JS stack. Leave a safety margin to prevent
   // overrunning the stack when pushing values.
@@ skipping 10643 matching lines @@
   return 0;
 }
 
 EVALUATE(KEB) {
   UNIMPLEMENTED();
   USE(instr);
   return 0;
 }
 
 EVALUATE(CEB) {
-  UNIMPLEMENTED();
-  USE(instr);
-  return 0;
+  DCHECK_OPCODE(CEB);
+
+  DECODE_RXE_INSTRUCTION(r1, b2, x2, d2);
+  int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
+  int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
+  intptr_t d2_val = d2;
+  float r1_val = get_float32_from_d_register(r1);
+  float fval = ReadFloat(b2_val + x2_val + d2_val);
+  SetS390ConditionCode<float>(r1_val, fval);
+  return length;
 }
 
 EVALUATE(AEB) {
   UNIMPLEMENTED();
   USE(instr);
   return 0;
 }
 
 EVALUATE(SEB) {
   UNIMPLEMENTED();
@@ skipping 288 matching lines @@
   return 0;
 }
 
 #undef EVALUATE
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // USE_SIMULATOR
 #endif  // V8_TARGET_ARCH_S390