Avoid trashing the FPSCR when calculating Math.floor...

src/arm/stub-cache-arm.cc

 // Copyright 2006-2009 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 1934 matching lines @@
   // They are invariant through a Math.Floor call, so just
   // return the original argument.
   __ sub(r7, r6, Operand(HeapNumber::kExponentMask
         >> HeapNumber::kMantissaBitsInTopWord), SetCC);
   __ b(&restore_fpscr_and_return, eq);
   // We had an overflow or underflow in the conversion. Check if we
   // have a big exponent.
   __ cmp(r7, Operand(HeapNumber::kMantissaBits));
   // If greater or equal, the argument is already round and in r0.
   __ b(&restore_fpscr_and_return, ge);
-  __ b(&slow);
+  __ b(&wont_fit_smi);
 
   __ bind(&no_vfp_exception);
   // Move the result back to general purpose register r0.
   __ vmov(r0, s0);
   // Check if the result fits into a smi.
   __ add(r1, r0, Operand(0x40000000), SetCC);
   __ b(&wont_fit_smi, mi);
   // Tag the result.
   STATIC_ASSERT(kSmiTag == 0);
   __ mov(r0, Operand(r0, LSL, kSmiTagSize));
 
   // Check for -0.
   __ cmp(r0, Operand(0, RelocInfo::NONE));
   __ b(&restore_fpscr_and_return, ne);
   // r5 already holds the HeapNumber exponent.
   __ tst(r5, Operand(HeapNumber::kSignMask));
   // If our HeapNumber is negative it was -0, so load its address and return.
   // Else r0 is loaded with 0, so we can also just return.
   __ ldr(r0, MemOperand(sp, 0 * kPointerSize), ne);
 
   __ bind(&restore_fpscr_and_return);
   // Restore FPSCR and return.
   __ vmsr(r3);
   __ Drop(argc + 1);
   __ Ret();
 
   __ bind(&wont_fit_smi);
-  __ bind(&slow);
   // Restore FPCSR and fall to slow case.
   __ vmsr(r3);
 
+  __ bind(&slow);
   // Tail call the full function. We do not have to patch the receiver
   // because the function makes no use of it.
   __ InvokeFunction(function, arguments(), JUMP_FUNCTION);
 
   __ bind(&miss);
   // r2: function name.
   MaybeObject* obj = GenerateMissBranch();
   if (obj->IsFailure()) return obj;
 
   // Return the generated code.
@@ skipping 1203 matching lines @@
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM