1 #include "threadimpl.h"
2 
3 void
4 makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
5 {
6 	int *sp;
7 
8 	sp = (int*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/4;
9 	sp -= argc;
10 	/*
11 	 * Stack pointer at call instruction (before return address
12 	 * gets pushed) must be 16-byte aligned.
13 	 */
14 	if((uintptr)sp%4)
15 		abort();
16 	while((uintptr)sp%16)
17 		sp--;
18 	memmove(sp, &argc+1, argc*sizeof(int));
19 	*--sp = 0;		/* return address */
20 	ucp->uc_mcontext.mc_eip = (long)func;
21 	ucp->uc_mcontext.mc_esp = (int)sp;
22 }
23 
24 int
25 swapcontext(ucontext_t *oucp, ucontext_t *ucp)
26 {
27 	if(getcontext(oucp) == 0)
28 		setcontext(ucp);
29 	return 0;
30 }
31