ARM: Enable the subnormal floats on QNX.

src/platform.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 380 matching lines @@
   // Copy memory area to disjoint memory area.
   static void MemCopy(void* dest, const void* src, size_t size) {
     memcpy(dest, src, size);
   }
   static void MemMove(void* dest, const void* src, size_t size) {
     memmove(dest, src, size);
   }
   static const int kMinComplexMemCopy = 16 * kPointerSize;
 #endif  // V8_TARGET_ARCH_IA32
 
+  // Perform the per-thread setup necessary for specific OSes and CPUs.
+  static void PerThreadSetUp() {
+#if V8_OS_QNX && defined(V8_HOST_ARCH_ARM)
+    // Clear the ARM_VFP_FPSCR_FZ flag in the FPSCR register.
+    // This disables the flush-to-zero mode in the VFP, allowing
+    // the handling of subnormals.
+    asm volatile(
+        "vmrs r3, fpscr          \n\t"
+        "bic  r3, r3, 0x01000000 \n\t"
+        "vmsr fpscr, r3"
+        : : : "r3");
+#endif  // V8_OS_QNX && V8_HOST_ARCH_ARM
+  }
+
   static int GetCurrentProcessId();
 
  private:
   static const int msPerSecond = 1000;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(OS);
 };
 
 // Represents and controls an area of reserved memory.
 // Control of the reserved memory can be assigned to another VirtualMemory
@@ skipping 199 matching lines @@
   char name_[kMaxThreadNameLength];
   int stack_size_;
   Semaphore* start_semaphore_;
 
   DISALLOW_COPY_AND_ASSIGN(Thread);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_