X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fuserprog.texi;h=aaf75e2aead1b749589d786f55e7ef12555d592f;hb=3edcfedb8e62970f3293fa676b6691f8658c3c11;hp=0872f798bd170d4319bdaf9a434b5cf156970c45;hpb=bbbad85235aaccd0d295e012133bca03918be6e5;p=pintos-anon

diff --git a/doc/userprog.texi b/doc/userprog.texi
index 0872f79..aaf75e2 100644
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -204,7 +204,7 @@ commands for copying files out of a VM are similar, but substitute
 @option{-g} for @option{-p}.
 
 Incidentally, these commands work by passing special commands
-@command{put} and @command{get} on the kernel's command line and copying
+@command{extract} and @command{append} on the kernel's command line and copying
 to and from a special simulated ``scratch'' disk.  If you're very
 curious, you can look at the @command{pintos} script as well as
 @file{filesys/fsutil.c} to learn the implementation details.
@@ -443,7 +443,7 @@ put_user (uint8_t *udst, uint8_t byte)
 {
   int error_code;
   asm ("movl $1f, %0; movb %b2, %1; 1:"
-       : "=&a" (error_code), "=m" (*udst) : "r" (byte));
+       : "=&a" (error_code), "=m" (*udst) : "q" (byte));
   return error_code != -1;
 }
 @end verbatim
@@ -1090,10 +1090,11 @@ pointers.
 
 Then, push the address of each string plus a null pointer sentinel, on
 the stack, in right-to-left order.  These are the elements of
-@code{argv}.  The order ensures that @code{argv[0]} is at the lowest
-virtual address.  Word-aligned accesses are faster than unaligned
-accesses, so for best performance round the stack pointer down to a
-multiple of 4 before the first push.
+@code{argv}.  The null pointer sentinel ensures that @code{argv[argc]}
+is a null pointer, as required by the C standard.  The order ensures
+that @code{argv[0]} is at the lowest virtual address.  Word-aligned
+accesses are faster than unaligned accesses, so for best performance
+round the stack pointer down to a multiple of 4 before the first push.
 
 Then, push @code{argv} (the address of @code{argv[0]}) and @code{argc},
 in that order.  Finally, push a fake ``return address'': although the