[webkit-dev] want to port JIT to MIPS - IEEE ques

[x yz]

1. Thanks for more info. Although X86 Linux gcc uses regparam(3), I think MIPS ABI always asks $a0~a3/@v0~v1 for i/o?
2. It seems I can get rid of 64bit OP if JIT_OPTIMIZE_ARITHMETIC and 
ALTERNATE_JSIMMEDIATE are both disabled? 
3. is it ALTERNATE_JSIMMEDIATE for ecma-262?
4. does JIT support floating point? if yes why it is not under jit/asm?
rgds
joe

--- On Wed, 1/28/09, Gavin Barraclough <barraclough at apple.com> wrote:

> From: Gavin Barraclough <barraclough at apple.com>
> Subject: Re: [webkit-dev] want to port JIT to MIPS, any coworker or any hint?
> To: lastguy at yahoo.com
> Date: Wednesday, January 28, 2009, 4:55 PM
> On Jan 27, 2009, at 10:58 PM, x yz wrote:
> 
> > Gavin,
> > last night I saw WREC when I search X86, and realized
> many places  
> > need to be touched. Your reply give more info and
> really help.  
> > Thanks a lot.
> >
> > In Generator::generateEnter(), there is comment
> "On gcc the function  
> > is regparm(3)...", how to understand that?
> 
> WREC JIT generates a function with a C calling convention
> that  
> implements the regular expression.  The entry and exit from
> the  
> function are generated by the generateEnter() and
> generateReturn*()  
> methods.  On OS X x86, the JIT generated function
> implements a  
> regparm(3) calling convention (see WREC.h, the generated
> code is  
> called through a CompiledRegExp function pointer).
> 
> > The function has no argument, why we peek four
> arguments from  
> > stack(input,output,length,index)?
> 
> These calls are not peeking values from the stack at the
> time they are  
> called; they are emitting JIT code that will will read
> values from the  
> stack, when the JIT function has been generated and is run.
>  The JIT  
> generated regular expression function is passed these four
> arguments  
> (again see WREC.h).
> 
> As a note, you're best directing these emails at the
> webkit-dev list  
> in future, that way other people will also be able to help
> you out.
> 
> cheers,
> G.
> 
> 
> >
> > rgds
> > joe
> >
> >
> > --- On Tue, 1/27/09, Gavin Barraclough
> <barraclough at apple.com> wrote:
> >
> >> From: Gavin Barraclough
> <barraclough at apple.com>
> >> Subject: Re: [webkit-dev] want to port JIT to
> MIPS, any coworker or  
> >> any hint?
> >> To: lastguy at yahoo.com
> >> Date: Tuesday, January 27, 2009, 5:10 AM
> >> On Jan 26, 2009, at 11:09 AM, x yz wrote:
> >>
> >>> Gavin,
> >>> Thanks, I really need to learn fast.
> >>> Where can I find more on WREC or its spec?
> >>
> >> WREC is WebKit's regular expression JIT.  The
> spec it
> >> is implementing is the regular expression syntax
> described
> >> in ECMA-262.
> >>
> >>> Which part of webkit is WREC? I just see all
> assembler
> >> codes are in <assembler> and <jit> and
> wonder
> >> whether I can just change them rather then change
> WREC.
> >>
> >> WebKit contains two separate JITs, one for the
> JavaScript
> >> language (in the 'jit' directory), one for
> >> JavaScript's regular expression language (in
> the
> >> 'wrec' directory).  Both JITs make use of
> the same
> >> assembler to emit code.  WREC is a much smaller,
> simpler
> >> JIT, which is why I suggest starting by looking at
> this, but
> >> either JIT can be enabled independently of the
> other.
> >>
> >>> Foresee SSE set may be a problem as MIPS has
> no SSE.
> >>
> >> WREC does not use SSE, and I believe all JIT code
> generated
> >> by the main JS JIT is guarded by the a
> configuration switch,
> >> JIT_OPTIMIZE_ARITHMETIC – this can be disabled
> in
> >> Platform.h.
> >>
> >>> Sun's link for "The JIT Compiler
> Interface
> >> Specification" not valid anymore.
> >>
> >> Our JIT is all our own code, and written from
> scratch, so
> >> I'm not sure this documentation would help
> you.
> >>
> >> Good luck,
> >> G.
> >>
> >>
> >>> MacroAssembler::breakpoint() is just int3
> which I know
> >> used as debug int in X86. I'll see which one
> used in gnu
> >> mips.
> >>> joe
> >>>
> >>>
> >>>
> >>> --- On Sun, 1/25/09, Gavin Barraclough
> >> <barraclough at apple.com> wrote:
> >>>
> >>>> From: Gavin Barraclough
> >> <barraclough at apple.com>
> >>>> Subject: Re: [webkit-dev] want to port JIT
> to
> >> MIPS, any coworker or any hint?
> >>>> To: "WebKit Development"
> >> <webkit-dev at lists.webkit.org>
> >>>> Date: Sunday, January 25, 2009, 5:34 PM
> >>>> On Jan 24, 2009, at 8:36 PM, x yz wrote:
> >>>>
> >>>>> Just build webkit on XP using cgywin,
> not
> >> tested yet.
> >>>> I want to port to 32bit MIPS, it seems I
> need to
> >> touch JIT
> >>>> and rewrite assembler folder.
> >>>>
> >>>> Once you have the bytecode interpreter up
> and
> >> running on
> >>>> MIPS, I'd recommend starting by just
> trying to
> >> port WREC
> >>>> (the regular expression JIT).  This is a
> good
> >> starting point
> >>>> because it utilizes a smaller subset of
> the
> >> MacroAssembler
> >>>> interface, and has a much simpler
> interface to C
> >> code (JIT
> >>>> code is called with C calling conventions,
> and no
> >> callbacks
> >>>> are made into C from the JIT generated
> code).
> >>>>
> >>>>> Any document there on
> javascripcore/assembler?
> >> I also
> >>>> want a smart way to make sure output is
> correct.
> >>>>
> >>>> A very simple way to validate you are
> generating
> >> the
> >>>> correct code is to simply force the JIT to
> insert
> >> a
> >>>> breakpoint (i.e. use
> MacroAssembler::breakpoint())
> >> at the
> >>>> head of the function you are generating,
> then run
> >> jsc under
> >>>> a debugger, and when it hits the
> breakpoint simply
> >>>> disassemble the code in memory at the
> point it has
> >> stopped.
> >>>> Now you can visually inspect that it it
> has
> >> generated the
> >>>> code you were expecting.
> >>>>
> >>>> Good luck!
> >>>> G.
> >>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >> _______________________________________________
> >>>>> webkit-dev mailing list
> >>>>> webkit-dev at lists.webkit.org
> >>>>>
> >>>>
> >>
> http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
> >>>>
> >>>>
> _______________________________________________
> >>>> webkit-dev mailing list
> >>>> webkit-dev at lists.webkit.org
> >>>>
> >>
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> >>>
> >>>
> >>>
> >
> >
> >