3 commits

Author	SHA1	Message	Date
Robert Morris	a82772594e	timer interrupts -> supervisor software interrupt	2019-06-04 14:20:37 -04:00
Robert Morris	0e131b2263	fix a problem with end. make uartputc() wait until h/w is ready.	2019-06-04 10:43:45 -04:00
Robert Morris	2ec1959fd1	fork/wait/exit work	2019-05-31 09:45:59 -04:00