Optimize truncated divide (intrinsics and inline).

vm/intrinsifier_ia32.cc

Index: vm/intrinsifier_ia32.cc
===================================================================
--- vm/intrinsifier_ia32.cc	(revision 2388)
+++ vm/intrinsifier_ia32.cc	(working copy)
@@ -34,6 +34,7 @@
   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)                       \
@@ -357,6 +358,25 @@
 }
 
 
+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));