[webkit-dev] want to port JIT to MIPS
lastguy at yahoo.com
Thu Feb 19 20:27:07 PST 2009
I'd appreaciate your help to clarify the problem I faced:
1.In JIT.cpp I roughly understand ctiTrampoline() except for sp-0x1C, I guess the 1C includes 6 argument yet the 7th or 1st may be the hidden C++ pointer? And the reserved 1C stack space seems not used? why esi is forced to be 512 rather than use input argument?
2.How to understand the stack balance in ctiVMThrowTrampoline()? why after calling we still add 1C w/o sub 1C before calling? where comes _ZN3JSC11Interpreter12cti_vm_throwEPPv and how do I know which name for Mips? does this one relates to variable argument function call?
3.I know how to handle jump in Mips, but not sure how/when to handle patchAddress/patchImm/patchPointer because I'm not sure the instructions related. I guess all patches are for last 32bit IMM field of instructions.
Mips can't load 32bit in one instruction, thus I need to know the instruction before I can patch/add in the 32bit data.
4.I'm kind of want no asm code outside <assembler> folder, any plan for that?
--- On Mon, 2/16/09, x yz <lastguy at yahoo.com> wrote:
> From: x yz <lastguy at yahoo.com>
> Subject: Re: [webkit-dev] want to port JIT to MIPS - when WREC/JIT enabled?
> To: "Gavin Barraclough" <barraclough at apple.com>
> Cc: "WebKit Development" <webkit-dev at lists.webkit.org>
> Date: Monday, February 16, 2009, 5:25 AM
> from paltform.h it is enabled only on X86 MAC/WIN; from
> But, from config.log I see them are enabled!
> how can I run WREC/JIT test so I can trace in X86 asm coce
> thanks a lot.
> --- On Sat, 2/7/09, Gavin Barraclough
> <barraclough at apple.com> wrote:
> > From: Gavin Barraclough <barraclough at apple.com>
> > Subject: Re: [webkit-dev] want to port JIT to MIPS -
> using X86::ecx as base
> > To: lastguy at yahoo.com
> > Cc: "WebKit Development"
> <webkit-dev at lists.webkit.org>
> > Date: Saturday, February 7, 2009, 7:08 AM
> > On Feb 6, 2009, at 2:52 PM, x yz wrote:
> > > 1.what's the meaning of ALTERNATE_JSIMMEDIATE
> > slow case?
> > On x86-64 we use a different implementation of the
> > JSImmediate. See JSImmediate.h.
> > Re 'slow case', in the JIT code generation is
> > performed as two passes over the bytecode – see
> > JIT::privateCompileMainPass and
> > JIT::privateCompileSlowCases.
> > > 2.how come the following code can use ECX as base
> > register?
> > > load32(Address(X86::ecx, FIELD_OFFSET(Structure,
> > m_typeInfo.m_flags)), X86::ecx);
> > > if the X86::ecx just means its value 1 in ModR/M,
> > it means [BX+DI]?
> > I think you're looking at the old 16-bit
> > mode tables; 32/64-bit x86 can happily encode ecx as a
> > register. If you're looking at the Intel IA-32
> > volume 2, see table 2-2 on the next page.
> > > 3. can anybody help me on my previous questions?
> > JIT support floating point?
> > Yes, some. See JITArithmetic.cpp.
> > cheers,
> > G.
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