Optimize truncated divide (intrinsics and inline).

vm/intrinsifier_ia32.cc

 // Copyright (c) 2011, 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 16 matching lines @@
 
 // List of intrinsics: (class-name, function-name, intrinsification method).
 #define INTRINSIC_LIST(V)                                                      \
   V(IntegerImplementation, addFromInteger, Integer_addFromInteger)             \
   V(IntegerImplementation, +, Integer_addFromInteger)                          \
   V(IntegerImplementation, subFromInteger, Integer_subFromInteger)             \
   V(IntegerImplementation, -, Integer_sub)                                     \
   V(IntegerImplementation, mulFromInteger, Integer_mulFromInteger)             \
   V(IntegerImplementation, *, Integer_mulFromInteger)                          \
   V(IntegerImplementation, %, Integer_modulo)                                  \
+  V(IntegerImplementation, ~/, Integer_truncDivide)                            \
   V(IntegerImplementation, negate, Integer_negate)                             \
   V(IntegerImplementation, bitAndFromInteger, Integer_bitAndFromInteger)       \
   V(IntegerImplementation, &, Integer_bitAndFromInteger)                       \
   V(IntegerImplementation, bitOrFromInteger, Integer_bitOrFromInteger)         \
   V(IntegerImplementation, |, Integer_bitOrFromInteger)                        \
   V(IntegerImplementation, bitXorFromInteger, Integer_bitXorFromInteger)       \
   V(IntegerImplementation, ^, Integer_bitXorFromInteger)                       \
   V(IntegerImplementation, greaterThanFromInteger, Integer_lessThan)           \
   V(IntegerImplementation, >, Integer_greaterThan)                             \
   V(IntegerImplementation, ==, Integer_equalToInteger)                         \
@@ skipping 303 matching lines @@
   __ movl(EAX, EBX);  // Return dividend.
   __ ret();
   __ Bind(&return_zero);
   __ xorl(EAX, EAX);  // Return zero.
   __ ret();
   __ Bind(&fall_through);
   return false;
 }
 
 
+static bool Integer_truncDivide(Assembler* assembler) {
+  Label fall_through;
+  TestBothArgumentsSmis(assembler, &fall_through);
+  // EAX: right argument (divisor)
+  __ cmpl(EAX, Immediate(0));
+  __ j(EQUAL, &fall_through, Assembler::kNearJump);
+  __ movl(EBX, EAX);
+  __ SmiUntag(EBX);
+  __ movl(EAX, Address(ESP, + 2 * kWordSize));  // Left argument (dividend).
+  __ SmiUntag(EAX);
+  __ cdq();
+  __ idivl(EBX);
+  __ SmiTag(EAX);

[sra1, 2011/12/13 21:12:08]

MIN_SMI / -1 is not a Smi.

[srdjan, 2011/12/13 21:29:35]

Thanks, fixing it now.

+  __ ret();
+  __ Bind(&fall_through);
+  return false;
+}
+
+
 static bool Integer_negate(Assembler* assembler) {
   Label fall_through;
   __ movl(EAX, Address(ESP, + 1 * kWordSize));
   __ testl(EAX, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, &fall_through, Assembler::kNearJump);  // Non-smi value.
   __ negl(EAX);
   __ j(OVERFLOW, &fall_through, Assembler::kNearJump);
   // Result is in EAX.
   __ ret();
   __ Bind(&fall_through);
@@ skipping 611 matching lines @@
   }                                                                            \
 
 INTRINSIC_LIST(FIND_INTRINSICS);
 #undef FIND_INTRINSICS
   return false;
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32