Przemyslaw,
GCC has this code inside libos2 which is linked with every program:
-----------8<--------------------
/* kbd4.c */
#define INCL_KBD
#include <os2.h>
USHORT _THUNK_FUNCTION (Kbd16CharIn) ();
USHORT KbdCharIn (PKBDKEYINFO pkbci, USHORT fWait, HKBD hkbd)
{
return ((USHORT)
(_THUNK_PROLOG (4+2+2);
_THUNK_FLAT (pkbci);
_THUNK_SHORT (fWait);
_THUNK_SHORT (hkbd);
_THUNK_CALL (Kbd16CharIn)));
}
----------->8--------------------
__THUNK defines are inside os2thunk.h which I attach, I don't grasp completely
what it does.
Does this shed some light?
Maurilio.
--
__________
| | | |__| Maurilio Longo
|_|_|_|____| farmaconsult s.r.l.
/* os2thunk.h,v 1.4 2004/09/14 22:27:35 bird Exp */
/** @file
* EMX
*/
#ifndef _OS2THUNK_H
#define _OS2THUNK_H
#include <sys/cdefs.h>
__BEGIN_DECLS
typedef unsigned long _far16ptr;
_far16ptr _libc_32to16 (void *ptr);
void *_libc_16to32 (_far16ptr ptr);
typedef union _thunk_u
{
void *pv;
unsigned short *pus;
unsigned long *pul;
} _thunk_t;
unsigned long _libc_thunk1 (void *args, void *fun);
#define _THUNK_PASCAL_PROLOG(SIZE) \
__extension__ ({ char _tb[(SIZE)+4]; _thunk_t _tu; _tu.pv = _tb + sizeof
(_tb); \
*(unsigned long *)_tb = (SIZE);
#define _THUNK_PASCAL_CHAR(ARG) _THUNK_PASCAL_SHORT (ARG)
#define _THUNK_PASCAL_SHORT(ARG) (*--_tu.pus = (ARG))
#define _THUNK_PASCAL_LONG(ARG) (*--_tu.pul = (ARG))
#define _THUNK_PASCAL_FLAT(ARG) _THUNK_PASCAL_LONG (_libc_32to16 (ARG))
#define _THUNK_PASCAL_FAR16(ARG) _THUNK_PASCAL_LONG (ARG)
#define _THUNK_PASCAL_FUNCTION(FUN) APIENTRY _16_##FUN
#define _THUNK_PASCAL_CALL(FUN) _libc_thunk1 (_tb, (void *)(_16_##FUN)); })
#define _THUNK_PASCAL_CALLI(FUN) _libc_thunk1 (_tb, (void *)(FUN)); })
#define _THUNK_C_PROLOG(SIZE) \
__extension__ ({ char _tb[(SIZE)+4]; _thunk_t _tu; _tu.pv = _tb + sizeof
(unsigned long); \
*(unsigned long *)_tb = (SIZE);
#define _THUNK_C_CHAR(ARG) _THUNK_C_SHORT (ARG)
#define _THUNK_C_SHORT(ARG) (*_tu.pus++ = (ARG))
#define _THUNK_C_LONG(ARG) (*_tu.pul++ = (ARG))
#define _THUNK_C_FLAT(ARG) _THUNK_C_LONG (_libc_32to16 (ARG))
#define _THUNK_C_FAR16(ARG) _THUNK_C_LONG (ARG)
#define _THUNK_C_FUNCTION(FUN) _16__##FUN
#define _THUNK_C_CALL(FUN) _libc_thunk1 (_tb, (void *)(_16__##FUN)); })
#define _THUNK_C_CALLI(FUN) _libc_thunk1 (_tb, (void *)(FUN)); })
#define _THUNK_PROLOG(SIZE) _THUNK_PASCAL_PROLOG (SIZE)
#define _THUNK_CHAR(ARG) _THUNK_PASCAL_CHAR (ARG)
#define _THUNK_SHORT(ARG) _THUNK_PASCAL_SHORT (ARG)
#define _THUNK_LONG(ARG) _THUNK_PASCAL_LONG (ARG)
#define _THUNK_FLAT(ARG) _THUNK_PASCAL_FLAT (ARG)
#define _THUNK_FAR16(ARG) _THUNK_PASCAL_FAR16 (ARG)
#define _THUNK_FUNCTION(FUN) _THUNK_PASCAL_FUNCTION (FUN)
#define _THUNK_CALL(FUN) _THUNK_PASCAL_CALL (FUN)
#define _THUNK_CALLI(FUN) _THUNK_PASCAL_CALLI (FUN)
#define MAKE16P(sel,off) ((_far16ptr)((sel) << 16 | (off)))
#define MAKEP(sel,off) _libc_16to32 (MAKE16P (sel, off))
#define SELECTOROF(farptr) ((SEL)((farptr) >> 16))
#define OFFSETOF(farptr) ((USHORT)(farptr))
/* Return true iff the block of SIZE bytes at PTR does not cross a
64Kbyte boundary. */
#define _THUNK_PTR_SIZE_OK(ptr,size) \
(((ULONG)(ptr) & ~0xffff) == (((ULONG)(ptr) + (size) - 1) & ~0xffff))
/* Return true iff the structure pointed to by PTR does not cross a
64KByte boundary. */
#define _THUNK_PTR_STRUCT_OK(ptr) _THUNK_PTR_SIZE_OK ((ptr), sizeof (*(ptr)))
__END_DECLS
#endif /* not _OS2THUNK_H */
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