#include "threadimpl.h" voidmakecontext(ucontext_t *ucp, void (*func)(void), int argc, ...){	ulong *sp, *tos;	va_list arg; 	tos = (ulong*)ucp->uc_stack.ss_sp+ucp->uc_stack.ss_size/sizeof(ulong);	sp = (ulong*)((ulong)(tos-16) & ~15);	ucp->mc.pc = (long)func;	ucp->mc.sp = (long)sp;	va_start(arg, argc);	ucp->mc.r3 = va_arg(arg, long);	va_end(arg);} intswapcontext(ucontext_t *oucp, ucontext_t *ucp){	if(getcontext(oucp) == 0)		setcontext(ucp);	return 0;}