SYS_mmap
(void) syscall(SYS_mmap, NULL, 1, 2, 3, -1, 0x12345678);
case SYS_mmap: /* set both if either */
sys = SYS_mmap;
if (__systemcall6(&rval, SYS_mmap, CHUNKSIZE, BASE_SIZE,
error = Psyscall(Pr, &rval, SYS_mmap, 6, &argd[0]);