From 6af21e6a4f2251e71353562d5df7f376fdffc270 Mon Sep 17 00:00:00 2001 From: Freya Murphy Date: Tue, 25 Mar 2025 17:36:52 -0400 Subject: initial checkout from wrc --- user/idle.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 user/idle.c (limited to 'user/idle.c') diff --git a/user/idle.c b/user/idle.c new file mode 100644 index 0000000..dbce885 --- /dev/null +++ b/user/idle.c @@ -0,0 +1,51 @@ +#include + +/** +** Idle process: write, getpid, gettime, exit +** +** Reports itself, then loops forever delaying and printing a character. +** MUST NOT SLEEP, as it must always be available in the ready queue +** when there is no other process to dispatch. +** +** Invoked as: idle +*/ + +USERMAIN( main ) { + // this is the character we will repeatedly print + char ch = '.'; + + // ignore the command-line arguments + (void) argc; + (void) argv; + + // get some current information + uint_t pid = getpid(); + uint32_t now = gettime(); + enum priority_e prio = getprio(); + + char buf[128]; + sprint( buf, "Idle [%d], started @ %u\n", pid, prio, now ); + cwrites( buf ); + + // report our presence on the console + cwrites( "Idle started\n" ); + + write( CHAN_SIO, &ch, 1 ); + + // idle() should never block - it must always be available + // for dispatching when we need to pick a new current process + + for(;;) { + DELAY(LONG); + write( CHAN_SIO, &ch, 1 ); + } + + // we should never reach this point! + now = gettime(); + sprint( buf, "Idle [%d] EXITING @ %u!?!?!\n", pid, now ); + cwrites( buf ); + + exit( 1 ); + + return( 42 ); +} -- cgit v1.2.3-freya