OpenEuphoria

RE: cdecl support

• Posted by Matthew Lewis <matthewwalkerlewis at YAHOO.COM> Feb 26, 2002
• 421 views

> -----Original Message-----
> From: euman at bellsouth.net [mailto:euman at bellsouth.net]

> I gave up about a week ago trying to get it to work properly.
> I  tried Matts routines, Mic has some routines in his GLU project
> and some of my own routines that never seemed to work right.
>
> I can get handles to the Euphoria routine but when a .dll requires
> that these routines (Eu routines) be cdecl also, I threw up my hands.
>
> I too would like a work around cause I wanted to use cabinet.dll
> to extract files from compressed MS-Cab's.
>
> Euman
> euman at bellsouth.net

> > From: "Brian Broker" <bkb at cnw.com>
> > For Matt Lewis and/or Euman:  Did you guys come up with a
> relatively
> > clean solution for defining cdecl callbacks?
> >
> > For Robert Craig:  How long before a 2.4 alpha with cdecl support?
> >
> > For anybody with source:  Anybody willing to build me a PD
> interpreter
> > with cdecl support?  I'm getting frustrated without it.

I finally had some time to look at the problem in detail.  I've got cdecl
callbacks to Euphoria working (ie, you can call Eu routines using cdecl),
and I think I figured out how to call a cdecl routine (had an epiphany right
before bed last night).  Here's how to make a cdecl callback:

-- Start code
include machine.e
include misc.e
include dll.e

constant
func_asm = {

    #55,                    --    0: push ebp
    #89,#E5,                --    1: mov ebp, esp
    #51,                    --    3: push ecx
    #B9,#00,#00,#00,#00,    --    4: mov ecx, argnum (5)
    #89,#E6,                --    9: mov esi, esp
    #83,#C6,#0C,            --    B: add esi, 12
    #BF,#00,#00,#00,#00,    --    E: mov edi, myargs (15)
    #F3,#A5,                --   13: rep movsd; next we call the proc

    #FF,#15,#00,#00,#00,#00,--   15: call dword ptr [pfunc] (#17)

    #59,                    --   1B: pop ecx
    #89,#EC,                --   1C: mov esp, ebp
    #5D,                    --   1E: pop ebp
    #C2,#00,#00,#00,#00}    --   1F: ret [argnum] (#20)


constant offset = length( func_asm )

global function new_pfunc_cdecl( atom callback, integer args )
    atom func_addr, func_retval, func_pfunc, func_args

    func_addr = allocate( length(func_asm) + 4 * 12  )
    poke( func_addr, func_asm )
    func_retval = func_addr + offset
    func_pfunc = func_retval + 4
    func_args = func_pfunc + 4

    poke4( func_addr + #05, args )
    poke4( func_addr + #0F, func_args )
    poke4( func_addr + #17, func_pfunc )
    --poke4( func_addr + #20, ( args + 0 ) * 4 )

    poke4( func_pfunc, callback )

    return { func_addr, func_args }
end function

atom my_cdecl_args
function my_cdecl_func()
    sequence args
    args = peek4u( {my_cdecl_args , 2})
    -- do stuff
    return 1
end func

object my_cdecl_callback

my_cdecl_callback = new_pfunc_cdecl( call_back(routine_id("my_cdecl_func")),
2 )

my_cdecl_args = my_cdecl_callback[2]
my_cdecl_callback = my_cdecl_callback[1]
-- Now you can pass my_cdecl_callback to a dll that uses cdecl