Port intrisification of setIndexed on Uint8 and Int8 arrays from ia32 to x64.

runtime/vm/intrinsifier_ia32.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // The intrinsic code below is executed before a method has built its frame.
 // The return address is on the stack and the arguments below it.
 // Registers EDX (arguments descriptor) and ECX (function) must be preserved.
 // Each intrinsification method returns true if the corresponding
 // Dart method was intrinsified.
 
@@ skipping 520 matching lines @@
 
 bool Intrinsifier::Int8Array_setIndexed(Assembler* assembler) {
   Label fall_through;
   // Verify that the array index is valid.
   TestByteArraySetIndex(assembler, &fall_through);
   // After TestByteArraySetIndex:
   // * EAX has the base address of the byte array.
   // * EBX has the index into the array.
   // EBX contains the SMI index which is shifted by 1.
   __ SmiUntag(EBX);
-  // Move EBX into EDI.
+  // Free EBX for the value since we want a byte register.
   __ movl(EDI, EBX);
-  // Load the value into EBX.
   __ movl(EBX, Address(ESP, + 1 * kWordSize));  // Value.
-  // If EBX is not an Smi, jump to fall through.
   __ testl(EBX, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, &fall_through, Assembler::kNearJump);
   __ SmiUntag(EBX);
-  // Add 128 to EBX to bring it into 0..FF.
+  // Check that the value is a byte. Add 128 to EBX to bring it into
+  // the range 0..FF.
   __ addl(EBX, Immediate(128));
   __ cmpl(EBX, Immediate(0xFF));
-  // If EBX is too large an Int8, jump to fall through.
   __ j(ABOVE, &fall_through, Assembler::kNearJump);
-  // Remove addition.
+  // Undo addition.
   __ subl(EBX, Immediate(128));
-  // Store BL into array EAX[EDI] = BL.
   __ movb(FieldAddress(EAX, EDI, TIMES_1, Int8Array::data_offset()), BL);
   __ ret();
   __ Bind(&fall_through);
   return false;
 }
 
 
 bool Intrinsifier::Uint8Array_getIndexed(Assembler* assembler) {
   Label fall_through;
   TestByteArrayIndex(assembler, &fall_through);
@@ skipping 11 matching lines @@
 
 bool Intrinsifier::Uint8Array_setIndexed(Assembler* assembler) {
   Label fall_through;
   // Verify that the array index is valid.
   TestByteArraySetIndex(assembler, &fall_through);
   // After TestByteArraySetIndex:
   // * EAX has the base address of the byte array.
   // * EBX has the index into the array.
   // EBX contains the SMI index which is shifted by 1.
   __ SmiUntag(EBX);
-  // Move EBX into EDI.
+  // Free EBX for the value since we want a byte register.
   __ movl(EDI, EBX);
-  // Load the value into EBX.
   __ movl(EBX, Address(ESP, + 1 * kWordSize));  // Value.
-  // If EBX is not an Smi, jump to fall through.
   __ testl(EBX, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, &fall_through, Assembler::kNearJump);
   __ SmiUntag(EBX);
-  // If EBX is too large an Uint8, jump to fall through.
+  // Check that the value is a byte.
   __ cmpl(EBX, Immediate(0xFF));
   __ j(ABOVE, &fall_through, Assembler::kNearJump);
-  // Store BL into array EAX[EDI] = BL.
   __ movb(FieldAddress(EAX, EDI, TIMES_1, Uint8Array::data_offset()), BL);
   __ ret();
   __ Bind(&fall_through);
   return false;
 }
 
 
 bool Intrinsifier::Int16Array_getIndexed(Assembler* assembler) {
   Label fall_through;
   TestByteArrayIndex(assembler, &fall_through);
@@ skipping 1129 matching lines @@
   __ Bind(&is_true);
   __ LoadObject(EAX, bool_true);
   __ ret();
   return true;
 }
 
 #undef __
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32