X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fuserprog.texi;h=fa3b4b8deb23d0a097249e7f1beefcb94d9cff9c;hb=659699f7814602571f17a88965ece50c7ebad0ad;hp=e3771e4e1aaf0f79e089841fa9d6432903737973;hpb=b7b1e6416ee6a167eeaad42553cbdd6e8f89e444;p=pintos-anon

diff --git a/doc/userprog.texi b/doc/userprog.texi
index e3771e4..fa3b4b8 100644
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -15,9 +15,7 @@ other part of the code for this assignment. We will describe the
 relevant parts below. If you are confident in your HW1 code, you can
 build on top of it.  However, if you wish you can start with a fresh
 copy of the code and re-implement @func{thread_join}, which is the
-only part of project #1 required for this assignment.  Your submission
-should define @code{THREAD_JOIN_IMPLEMENTED} in @file{constants.h}
-(@pxref{Conditional Compilation}).
+only part of project #1 required for this assignment.
 
 Up to now, all of the code you have written for Pintos has been part
 of the operating system kernel.  This means, for example, that all the
@@ -405,9 +403,9 @@ conditions (usually errors).
 @item SYS_exec
 @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, may return pid -1, which
-otherwise should not be a valid id number.
+given arguments, and returns the new process's program id (pid).  Must
+return pid -1, which otherwise should not be a valid program id, if
+there is an error loading this program.
 
 @item SYS_join
 @itemx int join (pid_t @var{pid})
@@ -516,9 +514,9 @@ recommend against modifying code in the @file{filesys} directory.}
 
 We have provided you a user-level function for each system call in
 @file{lib/user/syscall.c}.  These provide a way for user processes to
-invoke each system call from a C program.  Each of them calls an
-assembly language routine in @file{lib/user/syscall-stub.S}, which in
-turn invokes the system call interrupt and returns.
+invoke each system call from a C program.  Each uses a little inline
+assembly code to invoke the system call and (if appropriate) returns the
+system call's return value.
 
 When you're done with this part, and forevermore, Pintos should be
 bulletproof.  Nothing that a user program can do should ever cause the
@@ -686,7 +684,7 @@ provide a little bit of helpful code:
    Returns true if successful, false if USRC is invalid. */
 static inline bool get_user (uint8_t *dst, const uint8_t *usrc) {
   int eax;
-  asm ("movl $1f, %%eax; movb %2, %%al; movb %%al, %0; 1:"
+  asm ("mov %%eax, offset 1f; mov %%al, %2; mov %0, %%al; 1:"
        : "=m" (*dst), "=&a" (eax) : "m" (*usrc));
   return eax != 0;
 }
@@ -695,7 +693,7 @@ static inline bool get_user (uint8_t *dst, const uint8_t *usrc) {
    Returns true if successful, false if UDST is invalid. */
 static inline bool put_user (uint8_t *udst, uint8_t byte) {
   int eax;
-  asm ("movl $1f, %%eax; movb %b2, %0; 1:"
+  asm ("mov %%eax, offset 1f; mov %0, %b2; 1:"
        : "=m" (*udst), "=&a" (eax) : "r" (byte));
   return eax != 0;
 }