[src/trunk]: src/lib/libc/arch/sparc/gen A new implementation of _setjmp/_lon...

[pk <pk%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/ea6ea7fd6811
branches:  trunk
changeset: 474059:ea6ea7fd6811
user:      pk <pk%NetBSD.org@localhost>
date:      Sun Jun 27 11:10:18 1999 +0000

description:
A new implementation of _setjmp/_longjmp that uses the T_FLUSHWIN trap.
This means the stack frame and program counter can restored directly
from the jmp_buf, eliminating the need to backtrack through frames
which does not work in all cases.

diffstat:

 lib/libc/arch/sparc/gen/_setjmp.S |  95 ++++++++++++++++----------------------
 1 files changed, 39 insertions(+), 56 deletions(-)

diffs (133 lines):

diff -r ac4b559a6765 -r ea6ea7fd6811 lib/libc/arch/sparc/gen/_setjmp.S
--- a/lib/libc/arch/sparc/gen/_setjmp.S Sun Jun 27 10:00:36 1999 +0000
+++ b/lib/libc/arch/sparc/gen/_setjmp.S Sun Jun 27 11:10:18 1999 +0000
@@ -1,12 +1,11 @@
-/*     $NetBSD: _setjmp.S,v 1.5 1998/07/01 02:16:27 tv Exp $   */
+/*     $NetBSD: _setjmp.S,v 1.6 1999/06/27 11:10:18 pk Exp $   */
 
-/*
- * Copyright (c) 1992, 1993
- *     The Regents of the University of California.  All rights reserved.
+/*-
+ * Copyright (c) 1999 The NetBSD Foundation, Inc.
+ * All rights reserved.
  *
- * This software was developed by the Computer Systems Engineering group
- * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
- * contributed to Berkeley.
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Paul Kranenburg.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -18,34 +17,30 @@
  *    documentation and/or other materials provided with the distribution.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
- *     This product includes software developed by the University of
- *     California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
+ *        This product includes software developed by the NetBSD
+ *        Foundation, Inc. and its contributors.
+ * 4. Neither the name of The NetBSD Foundation nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
  *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * from: Header: _setjmp.s,v 1.1 91/07/06 16:45:53 torek Exp
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include <machine/asm.h>
+#include <machine/trap.h>
+
 #if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-       .asciz "@(#)_setjmp.s   8.1 (Berkeley) 6/4/93"
-#else
-       RCSID("$NetBSD: _setjmp.S,v 1.5 1998/07/01 02:16:27 tv Exp $")
-#endif
+RCSID("$NetBSD: _setjmp.S,v 1.6 1999/06/27 11:10:18 pk Exp $")
 #endif /* LIBC_SCCS and not lint */
 
 /*
@@ -55,42 +50,30 @@
  * will generate a "return(v?v:1)" from
  * the last call to
  *     _setjmp(a)
- * by unwinding the call stack.
  * The previous signal state is NOT restored.
  */
 
 ENTRY(_setjmp)
        st      %sp, [%o0+0]    /* store caller's stack pointer */
-       st      %o7, [%o0+4]    /* ... return pc */
-       st      %fp, [%o0+8]    /* ... and frame pointer */
+       st      %o7, [%o0+4]    /* and the return pc */
        retl
         clr    %o0             ! return 0
 
 ENTRY(_longjmp)
-       addcc   %o1, %g0, %g6   ! compute v ? v : 1 in a global register
+       sub     %sp, 64, %sp    ! set up a local stack frame
+       tst     %o1             ! compute v ? v : 1
        be,a    0f
-        mov    1, %g6
+        mov    1, %o1
 0:
-       mov     %o0, %g1        ! save a in another global register
-       ld      [%g1+8], %g7    /* get caller's frame */
-1:
-       cmp     %fp, %g7        ! compare against desired frame
-       bl,a    1b              ! if below,
-        restore                !    pop frame and loop
-       be,a    2f              ! if there,
-        ld     [%g1+0], %o2    !    fetch return %sp
+       t       ST_FLUSHWIN     ! flush register windows out to the stack
 
-Lbotch:
-       call    _C_LABEL(longjmperror)  ! otherwise, went too far; bomb out
-       nop
-       unimp   0
+       /*
+        * We restore the saved stack pointer to %fp, then issue
+        * a `restore' instruction which will reload the register
+        * window from the stack.
+        */
+       ld      [%o0+4], %o7    /* restore return pc */
+       ld      [%o0+0], %fp    /* and stack pointer */
 
-2:
-       cmp     %o2, %sp        ! %sp must not decrease
-       bge,a   3f
-        mov    %o2, %sp        ! it is OK, put it in place
-       b,a     Lbotch
-3:
-       ld      [%g1+4], %o3    ! fetch pc
-       jmp     %o3 + 8         ! success, return %g6
-        mov    %g6, %o0
+       retl                    ! success, return %g6
+        restore        %o1, 0, %o0