Comment only change: improve comments on VG_(clone) for x86 and AMD64.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@3771

diff --git a/coregrind/m_syscalls/syscall-amd64-linux.S b/coregrind/m_syscalls/syscall-amd64-linux.S
index 591b50d894ba3c20c0a0795add318b915ec53563..8ca293f048ee31ee5378c72bb90f355553a66192 100644 (file)
--- a/coregrind/m_syscalls/syscall-amd64-linux.S
+++ b/coregrind/m_syscalls/syscall-amd64-linux.S
@@ -83,12 +83,12 @@ VG_(do_syscall):
 
        System call requires:
 
+           int    $__NR_clone  in %rax
            int    flags        in %rdi
            void*  child_stack  in %rsi
            pid_t* parent_tid   in %rdx
            pid_t* child_tid    in %r10
            void*  tls_ptr      in %r8
-        
  */
 .globl VG_(clone)
 VG_(clone):

diff --git a/coregrind/m_syscalls/syscall-x86-linux.S b/coregrind/m_syscalls/syscall-x86-linux.S
index 4333b3b5ed5ca738916d790f29d0f13349f957fe..ea45472235a6308b333a3ce29b6d904be4ec45ff 100644 (file)
--- a/coregrind/m_syscalls/syscall-x86-linux.S
+++ b/coregrind/m_syscalls/syscall-x86-linux.S
@@ -71,11 +71,24 @@ VG_(do_syscall):
        fork()-like return-twice semantics, so it needs special
        handling here.
 
-       int VG_(clone)(int (*fn)(void *), void *child_stack, int flags, void *arg, 
-                      0                  4                  8          12
-                      pid_t *child_tid, pid_t *parent_tid, vki_modify_ldt_t *)
-                      16                20                 24
+       Upon entry, we have:
 
+           int (fn)(void*)     in  0+FSZ(%esp)
+           void* child_stack   in  4+FSZ(%esp)
+           int flags           in  8+FSZ(%esp)
+           void* arg           in 12+FSZ(%esp)
+           pid_t* child_tid    in 16+FSZ(%esp)
+           pid_t* parent_tid   in 20+FSZ(%esp)
+           void* tls_ptr       in 24+FSZ(%esp)
+
+       System call requires:
+
+           int    $__NR_clone  in %eax
+           int    flags        in %ebx
+           void*  child_stack  in %ecx
+           pid_t* parent_tid   in %edx
+           pid_t* child_tid    in %edi
+           void*  tls_ptr      in %esi
  */
 .globl VG_(clone)
 VG_(clone):
@@ -83,7 +96,7 @@ VG_(clone):
        push    %ebx
        push    %edi
        /* set up child stack with function and arg */
-       movl     4+FSZ(%esp), %ecx      /* child stack */
+       movl     4+FSZ(%esp), %ecx      /* syscall arg2: child stack */
        movl    12+FSZ(%esp), %ebx      /* fn arg */
        movl     0+FSZ(%esp), %eax      /* fn */
        lea     -8(%ecx), %ecx          /* make space on stack */
@@ -91,21 +104,21 @@ VG_(clone):
        movl    %eax, 0(%ecx)           /*   fn */
 
        /* get other args to clone */
-       movl     8+FSZ(%esp), %ebx      /* flags */
-       movl    20+FSZ(%esp), %edx      /* parent tid * */
-       movl    16+FSZ(%esp), %edi      /* child tid * */
-       movl    24+FSZ(%esp), %esi      /* modify_ldt_t * */
+       movl     8+FSZ(%esp), %ebx      /* syscall arg1: flags */
+       movl    20+FSZ(%esp), %edx      /* syscall arg3: parent tid * */
+       movl    16+FSZ(%esp), %edi      /* syscall arg4: child tid * */
+       movl    24+FSZ(%esp), %esi      /* syscall arg5: tls_ptr * */
        movl    $__NR_clone, %eax
-       int     $0x80
-       testl   %eax, %eax
+       int     $0x80                   /* clone() */
+       testl   %eax, %eax              /* child if retval == 0 */
        jnz     1f
 
        /* CHILD - call thread function */
        popl    %eax
-       call    *%eax
+       call    *%eax                   /* call fn */
 
        /* exit with result */
-       movl    %eax, %ebx
+       movl    %eax, %ebx              /* arg1: return value from fn */
        movl    $__NR_exit, %eax
        int     $0x80