_vcomp_fork stack frame puzzle

[Dan Kegel]

Yes indeed, this works:

extern void WINAPIV VCOMP__vcomp_fork(DWORD parallel, int ncount, void
(__cdecl *helper)(__ms_va_list), ...);
__ASM_GLOBAL_FUNC( VCOMP__vcomp_fork,
                   "pop %eax\n\t"           /* save return address */
                   "add $8,%esp\n\t"        /* skip parallel and ncount */
                   "pop %ebx\n\t"           /* save helper */
                   "push %eax\n\t"          /* set up return address */
                   "jmp %ebx"               /* enter handler */
                 )