s390: improve floating point and integer convertion

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 6247 matching lines @@
   float r2_val = get_float32_from_d_register(r2);
   uint32_t r1_val = static_cast<uint32_t>(r2_val);
   set_low_register(r1, r1_val);
   SetS390ConvertConditionCode<double>(r2_val, r1_val, UINT32_MAX);
   return length;
 }
 
 EVALUATE(CLFDBR) {
   DCHECK_OPCODE(CLFDBR);
   DECODE_RRE_INSTRUCTION(r1, r2);
-  double r2_val = get_double_from_d_register(r2);
-  uint32_t r1_val = static_cast<uint32_t>(r2_val);
+  double a = get_double_from_d_register(r2);
+  double n = std::round(a);
+  uint32_t r1_val = static_cast<uint32_t>(n);
   set_low_register(r1, r1_val);
-  SetS390ConvertConditionCode<double>(r2_val, r1_val, UINT32_MAX);
+  if (std::isfinite(a) && a < 0.0) {
+    DCHECK(n <= 0.0 && std::isfinite(n));
+    condition_reg_ = (n < 0.0) ? 0x1 : 0x4;
+  } else if (a == 0.0) {
+    condition_reg_ = 0x8;
+  } else if (std::isfinite(a) && a > 0.0) {
+    DCHECK(n >= 0.0 && std::isfinite(n));
+    condition_reg_ = (n <= static_cast<double>(UINT32_MAX)) ? 0x2 : 0x1;
+  } else {
+    condition_reg_ = 0x1;
+  }
   return length;
 }
 
 EVALUATE(CLFXBR) {
   UNIMPLEMENTED();
   USE(instr);
   return 0;
 }
 
 EVALUATE(CELGBR) {
@@ skipping 3532 matching lines @@
   return 0;
 }
 
 #undef EVALUATE
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // USE_SIMULATOR
 #endif  // V8_TARGET_ARCH_S390