X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fuserprog.texi;h=25b7a70b7c6679bae217742b8e5203060b29abf3;hb=064e19becdc8969ddb605223b340606706a33f86;hp=525e8ced27e8699604c223a7996c4cd5bf9e5710;hpb=031abf164a9867f8f65d724eeeb298dc5f4ae8a6;p=pintos-anon

diff --git a/doc/userprog.texi b/doc/userprog.texi
index 525e8ce..25b7a70 100644
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -254,6 +254,19 @@ another reason.  The name printed should be the full name passed to
 @func{process_execute}, except that it is acceptable to truncate it to
 15 characters to allow for the limited space in @struct{thread}.
 
+@itemize @minus
+@item
+Do not print a message when a kernel thread that is not a process
+terminates.
+
+@item
+Do not print messages about process termination for the @code{halt}
+system call.
+
+@item
+No message need be printed when a process that fails to load.
+@end itemize
+
 @item
 Aside from this, the kernel should print out no other messages that
 Pintos as provided doesn't already print.  You
@@ -345,7 +358,7 @@ conditions (usually errors).
 @itemx pid_t exec (const char *@var{cmd_line})
 Runs the executable whose name is given in @var{cmd_line}, passing any
 given arguments, and returns the new process's program id (pid).  If
-there is an error loading this program, returns pid -1, which
+there is an error loading this program, may return pid -1, which
 otherwise should not be a valid id number.
 
 @item SYS_join
@@ -507,7 +520,8 @@ isn't properly set up yet, this causes a page fault.
 @samp{system call!}.}
 
 Every reasonable program tries to make at least one system call
-(@func{exit}) and most programs make more than that.  The default
+(@func{exit}) and most programs make more than that.  Notably,
+@func{printf} invokes the @code{write} system call.  The default
 system call handler just prints @samp{system call!} and terminates the
 program.  You'll have to implement 2-2 before you see anything more
 interesting.  Until then, you can use @func{hex_dump} to convince
@@ -818,7 +832,7 @@ After we push all of the strings onto the stack, we adjust the stack
 pointer so that it is word-aligned: that is, we move it down to the
 next 4-byte boundary.  This is required because we will next be
 placing several words of data on the stack, and they must be aligned
-in order to be read correctly.  In our example, as you'll see below,
+to be read correctly.  In our example, as you'll see below,
 the strings start at address @t{0xffed}.  One word below that would be
 at @t{0xffe9}, so we could in theory put the next word on the stack
 there.  However, since the stack pointer should always be