2003-04-06 Roland McGrath <roland@redhat.com>

	* sysdeps/unix/sysv/linux/i386/swapcontext.S: Rewrite register
	restoration as done for setcontext yesterday.

diff --git a/sysdeps/unix/sysv/linux/i386/swapcontext.S b/sysdeps/unix/sysv/linux/i386/swapcontext.S
index e44e930..d909e65 100644 (file)
--- a/sysdeps/unix/sysv/linux/i386/swapcontext.S
+++ b/sysdeps/unix/sysv/linux/i386/swapcontext.S
@@ -1,5 +1,5 @@
 /* Save current context and install the given one.
-   Copyright (C) 2001, 2002 Free Software Foundation, Inc.
+   Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 2001.
 
@@ -78,43 +78,31 @@ ENTRY(__swapcontext)
        movl    oFPREGS(%eax), %ecx
        fldenv  (%ecx)
 
-       /* Restore the FS segment registers.  */
+       /* Restore the FS segment register.  We don't touch the GS register
+          since it is used for threads.  */
        movl    oFS(%eax), %edx
        movw    %dx, %fs
 
+       /* Fetch the address to return to.  */
+       movl    oEIP(%eax), %ecx
+
        /* Load the new stack pointer.  */
-       movl    oESP(%eax), %ecx
-       /* Make room for 8 registers and the return address.  We will load
-          the values from the stack.  */
-       subl    $36, %ecx
-
-       /* Move the values of all the 32-bit registers (except ESP) on
-          the stack.  This happens in the form the 'popa' instruction
-          expects it.  Before this block put the address of the code
-          to execute.  */
-       movl    oEDI(%eax), %ebx
-       movl    oESI(%eax), %edx
-       movl    oEBP(%eax), %esi
-       movl    oEBX(%eax), %edi
-       movl    %ebx, (%ecx)
-       movl    %edx, 4(%ecx)
-       movl    %esi, 8(%ecx)
-       movl    %edi, 16(%ecx)
-       movl    oEDX(%eax), %ebx
-       movl    oECX(%eax), %edx
-       movl    oEAX(%eax), %esi
-       movl    oEIP(%eax), %edi
-       movl    %ebx, 20(%ecx)
-       movl    %edx, 24(%ecx)
-       movl    %esi, 28(%ecx)
-       movl    %edi, 32(%ecx)
-
-       /* Set the new stack address.  The stack points now to the block
-          we put the register content in.  */
-       movl    %ecx, %esp
-       /* Restore the register content.  */
-       popa
-       /* The following 'ret' will pop the addres of the code and jump
+       movl    oESP(%eax), %esp
+
+       /* Push the return address on the new stack so we can return there.  */
+       pushl   %ecx
+
+       /* Load the values of all the 32-bit registers (except ESP).
+          Since we are loading from EAX, it must be last.  */
+       movl    oEDI(%eax), %edi
+       movl    oESI(%eax), %esi
+       movl    oEBP(%eax), %ebp
+       movl    oEBX(%eax), %ebx
+       movl    oEDX(%eax), %edx
+       movl    oECX(%eax), %ecx
+       movl    oEAX(%eax), %eax
+
+       /* The following 'ret' will pop the address of the code and jump
           to it.  */
 
 L(pseudo_end):