1 41b3e8b9 2020-01-20 rsc #include "threadimpl.h"
 2 41b3e8b9 2020-01-20 rsc 
 3 41b3e8b9 2020-01-20 rsc void
 4 41b3e8b9 2020-01-20 rsc makecontext(ucontext_t *uc, void (*fn)(void), int argc, ...)
 5 41b3e8b9 2020-01-20 rsc {
 6 41b3e8b9 2020-01-20 rsc 	uintptr *sp;
 7 41b3e8b9 2020-01-20 rsc 	va_list arg;
 8 41b3e8b9 2020-01-20 rsc 
 9 41b3e8b9 2020-01-20 rsc 	if(argc != 2)
10 41b3e8b9 2020-01-20 rsc 		sysfatal("libthread: makecontext misused");
11 41b3e8b9 2020-01-20 rsc 	va_start(arg, argc);
12 41b3e8b9 2020-01-20 rsc 	uc->mc.di = va_arg(arg, uint);
13 41b3e8b9 2020-01-20 rsc 	uc->mc.si = va_arg(arg, uint);
14 41b3e8b9 2020-01-20 rsc 	va_end(arg);
15 41b3e8b9 2020-01-20 rsc 
16 41b3e8b9 2020-01-20 rsc 	sp = USPALIGN(uc, 16);
17 41b3e8b9 2020-01-20 rsc 	*--sp = 0;  // fn's return address
18 41b3e8b9 2020-01-20 rsc 	*--sp = (uintptr)fn;  // return address of setcontext
19 41b3e8b9 2020-01-20 rsc 	uc->mc.sp = (uintptr)sp;
20 41b3e8b9 2020-01-20 rsc }
21 41b3e8b9 2020-01-20 rsc 
22 41b3e8b9 2020-01-20 rsc int
23 41b3e8b9 2020-01-20 rsc swapcontext(ucontext_t *oucp, ucontext_t *ucp)
24 41b3e8b9 2020-01-20 rsc {
25 41b3e8b9 2020-01-20 rsc 	if(getcontext(oucp) == 0)
26 41b3e8b9 2020-01-20 rsc 		setcontext(ucp);
27 41b3e8b9 2020-01-20 rsc 	return 0;
28 41b3e8b9 2020-01-20 rsc }