AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

ARM: Special case for modulus of two smis in the generic binary opration stub

Browse Source 
When lhs and rhs are positive smis and rhs is a power of two perform modulus by masking.
Review URL: http://codereview.chromium.org/2873001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4884 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
sgjesse@chromium.org 2010-06-16 20:03:32 +00:00
parent e6ea484e1f
commit 50a2e15bbd
1 changed files with 22 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
src/arm/codegen-arm.cc
View File

@ -8164,6 +8164,28 @@ void GenericBinaryOpStub::Generate(MacroAssembler* masm) {
}
__ Ret();
__ bind(&smi_is_unsuitable);
} else if (op_ == Token::MOD &&
runtime_operands_type_ != BinaryOpIC::HEAP_NUMBERS &&
runtime_operands_type_ != BinaryOpIC::STRINGS) {
// Do generate a bit of smi code for modulus even though the default for
// modulus is not to do it, but as the ARM processor has no coprocessor
// support for modulus checking for smis makes sense.
Label slow;
ASSERT(!ShouldGenerateSmiCode());
ASSERT(kSmiTag == 0); // Adjust code below.
// Check for two positive smis.
__ orr(smi_test_reg, lhs, Operand(rhs));
__ tst(smi_test_reg, Operand(0x80000000u | kSmiTagMask));
__ b(ne, &slow);
// Check that rhs is a power of two and not zero.
__ sub(scratch, rhs, Operand(1), SetCC);
__ b(mi, &slow);
__ tst(rhs, scratch);
__ b(ne, &slow);
// Calculate power of two modulus.
__ and_(result, lhs, Operand(scratch));
__ Ret();
__ bind(&slow);
}
HandleBinaryOpSlowCases(
masm,