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cdecl.c
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cdecl.c
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/* cdecl.h is generated when you run `perl Makefile.PL DECL=cdecl' */
#include "cdecl.h"
/*
* Convert Perl sub args to C args and pass them to (*func)().
* Caller cleanup.
* See http://en.wikipedia.org/wiki/X86_calling_conventions
*/
static int
cdecl_pray(ax, items, func)
I32 ax; /* used by the ST() macro */
I32 items;
void *func;
{
#ifdef USE_THREADS
dTHR;
#endif
/* DYNALIB_ARGSTART = 3 because of three locals here. */
STRLEN arg_len;
char *arg_scalar, *arg_on_stack;
register int i;
#if CDECL_ONE_BY_ONE
#if CDECL_REVERSE
for (i = DYNALIB_ARGSTART; i < items; i++) {
#else /* ! CDECL_REVERSE */
for (i = items - 1; i >= DYNALIB_ARGSTART; i--) {
#endif /* ! CDECL_REVERSE */
arg_scalar = SvPV(ST(i), arg_len);
arg_on_stack = alloca(arg_len);
Copy(arg_scalar, arg_on_stack, arg_len, char);
}
#else /* ! CDECL_ONE_BY_ONE */
STRLEN total_arg_len = 0;
for (i = items; i-- > DYNALIB_ARGSTART; ) {
(void) SvPV(ST(i), arg_len);
/* XXX CDECL_ARG_ALIGN=8 for amd64 */
total_arg_len += arg_len;
}
arg_on_stack = (char *) alloca(total_arg_len);
arg_on_stack += CDECL_ADJUST;
#if CDECL_REVERSE
for (i = items - 1; i >= DYNALIB_ARGSTART; i--) {
#else /* ! CDECL_REVERSE */
for (i = DYNALIB_ARGSTART; i < items; i++) {
#endif /* ! CDECL_REVERSE */
arg_scalar = SvPV(ST(i), arg_len);
#ifdef __x86_64__
if (arg_len < 8) {
/* x86_64 aligns to 8 non zero-filled.
http://blogs.msdn.com/oldnewthing/archive/2004/01/14/58579.aspx
*/
memzero(arg_on_stack, 8);
}
#endif
Copy(arg_scalar, arg_on_stack, arg_len, char);
arg_on_stack += arg_len;
}
#endif /* ! CDECL_ONE_BY_ONE */
/* Cross your fingers. */
return (*((int (*)()) func))();
}
#if defined(__GNUC__) && __GNUC__ >= 3 && defined(__GNUC_MINOR__) && (__GNUC_MINOR__ >= 3)
#define cdecl_CALL(func, type) \
(type)((*((int (*)()) cdecl_pray))(ax,items,func))
#else
#define cdecl_CALL(func, type) \
((*((type (*)()) cdecl_pray))(ax,items,func))
#endif