Make use of VFP to convert/write 32bits int to heapnumbers. Extended...

src/arm/codegen-arm.cc

 // Copyright 2010 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 7894 matching lines @@
       __ and_(r2, r2, Operand(0x1f));
       __ mov(r2, Operand(r3, ASR, r2));
       break;
     case Token::SHR:
       // Use only the 5 least significant bits of the shift count.
       __ and_(r2, r2, Operand(0x1f));
       __ mov(r2, Operand(r3, LSR, r2), SetCC);
       // SHR is special because it is required to produce a positive answer.
       // The code below for writing into heap numbers isn't capable of writing
       // the register as an unsigned int so we go to slow case if we hit this
       // case.

[Erik Corry, 2010/07/01 14:56:47]

If we have VFP3 we don't have to bail out here.  We can jump to result_not_a_smi
instead.  You just have to use a vcvt_f64_u32 instead of the signed one.

       __ b(mi, &slow);
       break;
     case Token::SHL:
       // Use only the 5 least significant bits of the shift count.
       __ and_(r2, r2, Operand(0x1f));
       __ mov(r2, Operand(r3, LSL, r2));
       break;
     default: UNREACHABLE();
   }
   // check that the *signed* result fits in a smi
@@ skipping 24 matching lines @@
     default: break;
   }
   __ bind(&got_a_heap_number);
   // r2: Answer as signed int32.
   // r5: Heap number to write answer into.
 
   // Nothing can go wrong now, so move the heap number to r0, which is the
   // result.
   __ mov(r0, Operand(r5));
 
-  // Tail call that writes the int32 in r2 to the heap number in r0, using
-  // r3 as scratch.  r0 is preserved and returned.
-  WriteInt32ToHeapNumberStub stub(r2, r0, r3);
-  __ Jump(stub.GetCode(), RelocInfo::CODE_TARGET);
+  if (CpuFeatures::IsSupported(VFP3)) {
+    // Convert the int32 in r2 to the heap number in r0. r3 is corrupted.
+    CpuFeatures::Scope scope(VFP3);
+    __ vmov(s0, r2);
+    __ vcvt_f64_s32(d0, s0);
+    __ sub(r3, r0, Operand(kHeapObjectTag));
+    __ vstr(d0, r3, HeapNumber::kValueOffset);
+    __ Ret();
+  } else {
+    // Tail call that writes the int32 in r2 to the heap number in r0, using
+    // r3 as scratch.  r0 is preserved and returned.
+    WriteInt32ToHeapNumberStub stub(r2, r0, r3);
+    __ TailCallStub(&stub);
+  }
 
   if (mode_ != NO_OVERWRITE) {
     __ bind(&have_to_allocate);
     // Get a new heap number in r5.  r4 and r7 are scratch.
     __ AllocateHeapNumber(r5, r4, r7, heap_number_map, &slow);
     __ jmp(&got_a_heap_number);
   }
 
   // If all else failed then we go to the runtime system.
   __ bind(&slow);
@@ skipping 828 matching lines @@
 
     __ bind(&try_float);
     if (!overwrite_) {
       // Allocate a fresh heap number, but don't overwrite r0 until
       // we're sure we can do it without going through the slow case
       // that needs the value in r0.
       __ AllocateHeapNumber(r2, r3, r4, r6, &slow);
       __ mov(r0, Operand(r2));
     }
 
-    // WriteInt32ToHeapNumberStub does not trigger GC, so we do not
-    // have to set up a frame.
-    WriteInt32ToHeapNumberStub stub(r1, r0, r2);
-    __ push(lr);
-    __ Call(stub.GetCode(), RelocInfo::CODE_TARGET);
-    __ pop(lr);
+    if (CpuFeatures::IsSupported(VFP3)) {
+      // Convert the int32 in r1 to the heap number in r0. r2 is corrupted.
+      CpuFeatures::Scope scope(VFP3);
+      __ vmov(s0, r1);
+      __ vcvt_f64_s32(d0, s0);
+      __ sub(r2, r0, Operand(kHeapObjectTag));
+      __ vstr(d0, r2, HeapNumber::kValueOffset);
+    } else {
+      // WriteInt32ToHeapNumberStub does not trigger GC, so we do not
+      // have to set up a frame.
+      WriteInt32ToHeapNumberStub stub(r1, r0, r2);
+      __ push(lr);
+      __ Call(stub.GetCode(), RelocInfo::CODE_TARGET);
+      __ pop(lr);
+    }
   } else {
     UNIMPLEMENTED();
   }
 
   __ bind(&done);
   __ StubReturn(1);
 
   // Handle the slow case by jumping to the JavaScript builtin.
   __ bind(&slow);
   __ push(r0);
@@ skipping 2214 matching lines @@
   __ bind(&string_add_runtime);
   __ TailCallRuntime(Runtime::kStringAdd, 2, 1);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM