Revise.

[pintos-anon] / doc / userprog.texi

diff --git a/doc/userprog.texi b/doc/userprog.texi
index 32934965f4c44cc805de4b930ea4f56be4436ce2..25b7a70b7c6679bae217742b8e5203060b29abf3 100644 (file)
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -520,7 +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
@@ -831,7 +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