https://bugs.webkit.org/show_bug.cgi?id=31159
Fix branchDouble behaviour on ARM THUMB2 JIT.
Patch by Zoltan Herczeg <zherczeg@inf.u-szeged.hu> on 2009-11-05
Reviewed by Gavin Barraclough.
The x86 branchDouble behaviour is reworked, and all JIT
ports should follow the x86 port. See bug 31104 and 31151
This patch contains a fix for the traditional ARM port
* assembler/ARMAssembler.h:
(JSC::ARMAssembler::):
(JSC::ARMAssembler::fmrs_r):
(JSC::ARMAssembler::ftosid_r):
* assembler/MacroAssemblerARM.h:
(JSC::MacroAssemblerARM::):
(JSC::MacroAssemblerARM::branchDouble):
(JSC::MacroAssemblerARM::branchConvertDoubleToInt32):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@50593 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/JavaScriptCore/assembler/MacroAssemblerARM.h b/JavaScriptCore/assembler/MacroAssemblerARM.h
index a06797e..6d309aa 100644
--- a/JavaScriptCore/assembler/MacroAssemblerARM.h
+++ b/JavaScriptCore/assembler/MacroAssemblerARM.h
@@ -38,6 +38,9 @@
namespace JSC {
class MacroAssemblerARM : public AbstractMacroAssembler<ARMAssembler> {
+ static const int DoubleConditionMask = 0x0f;
+ static const int DoubleConditionBitSpecial = 0x10;
+ COMPILE_ASSERT(!(DoubleConditionBitSpecial & DoubleConditionMask), DoubleConditionBitSpecial_should_not_interfere_with_ARMAssembler_Condition_codes);
public:
enum Condition {
Equal = ARMAssembler::EQ,
@@ -57,9 +60,18 @@
};
enum DoubleCondition {
- DoubleEqualOrUnordered = ARMAssembler::EQ,
+ // These conditions will only evaluate to true if the comparison is ordered - i.e. neither operand is NaN.
+ DoubleEqual = ARMAssembler::EQ,
+ DoubleNotEqual = ARMAssembler::NE | DoubleConditionBitSpecial,
DoubleGreaterThan = ARMAssembler::GT,
DoubleGreaterThanOrEqual = ARMAssembler::GE,
+ DoubleLessThan = ARMAssembler::CC,
+ DoubleLessThanOrEqual = ARMAssembler::LS,
+ // If either operand is NaN, these conditions always evaluate to true.
+ DoubleEqualOrUnordered = ARMAssembler::EQ | DoubleConditionBitSpecial,
+ DoubleNotEqualOrUnordered = ARMAssembler::NE,
+ DoubleGreaterThanOrUnordered = ARMAssembler::HI,
+ DoubleGreaterThanOrEqualOrUnordered = ARMAssembler::CS,
DoubleLessThanOrUnordered = ARMAssembler::LT,
DoubleLessThanOrEqualOrUnordered = ARMAssembler::LE,
};
@@ -714,7 +726,9 @@
{
m_assembler.fcmpd_r(left, right);
m_assembler.fmstat();
- return Jump(m_assembler.jmp(static_cast<ARMAssembler::Condition>(cond)));
+ if (cond & DoubleConditionBitSpecial)
+ m_assembler.cmp_r(ARMRegisters::S0, ARMRegisters::S0, ARMAssembler::VS);
+ return Jump(m_assembler.jmp(static_cast<ARMAssembler::Condition>(cond & ~DoubleConditionMask)));
}
// Truncates 'src' to an integer, and places the resulting 'dest'.
@@ -729,6 +743,23 @@
return jump();
}
+ // Convert 'src' to an integer, and places the resulting 'dest'.
+ // If the result is not representable as a 32 bit value, branch.
+ // May also branch for some values that are representable in 32 bits
+ // (specifically, in this case, 0).
+ void branchConvertDoubleToInt32(FPRegisterID src, RegisterID dest, JumpList& failureCases, FPRegisterID fpTemp)
+ {
+ m_assembler.ftosid_r(src, ARMRegisters::SD0);
+ m_assembler.fmrs_r(ARMRegisters::SD0, dest);
+
+ // Convert the integer result back to float & compare to the original value - if not equal or unordered (NaN) then jump.
+ m_assembler.fsitod_r(ARMRegisters::SD0, ARMRegisters::SD0);
+ failureCases.append(branchDouble(DoubleNotEqual, src, ARMRegisters::SD0));
+
+ // If the result is zero, it might have been -0.0, and 0.0 equals to -0.0
+ failureCases.append(branchTest32(Zero, dest));
+ }
+
protected:
ARMAssembler::Condition ARMCondition(Condition cond)
{
