/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1988 AT&T */
/*        All Rights Reserved   */

        .file   "setjmp.s"

#include <sys/asm_linkage.h>

        ANSI_PRAGMA_WEAK(setjmp,function)
        ANSI_PRAGMA_WEAK(longjmp,function)

#include <../assym.h>
#include <sys/trap.h>

JB_FLAGS        = (0*4) ! offsets in jmpbuf (see siglonglmp.c)
JB_SP           = (1*4) ! words 5 through 11 are unused!
JB_PC           = (2*4)
JB_FP           = (3*4)
JB_I7           = (4*4)

/*
 * Flag telling longjmp to set curthread->ul_siglink to NULL.
 */
JB_CLEARLINK    = 0x10

/*
 * setjmp(buf_ptr)
 * buf_ptr points to a twelve word array (jmp_buf)
 */
        ENTRY(setjmp)
        clr     %o2
        ld      [%g7 + UL_SIGLINK], %o1 ! are we in a signal context?
        tst     %o1
        be,a,pt %icc, 1f
        mov     JB_CLEARLINK, %o2       ! no, tell longjmp to clear ul_siglink
1:      st      %o2, [%o0 + JB_FLAGS]
        st      %sp, [%o0 + JB_SP]      ! save caller's sp
        add     %o7, 8, %o1             ! compute return pc
        st      %o1, [%o0 + JB_PC]      ! save pc
        st      %fp, [%o0 + JB_FP]      ! save fp
        st      %i7, [%o0 + JB_I7]      ! save %i7
        retl
        clr     %o0                     ! return (0)

        SET_SIZE(setjmp)

/*
 * longjmp(buf_ptr, val)
 * buf_ptr points to a jmpbuf which has been initialized by setjmp.
 * val is the value we wish to return to setjmp's caller
 *
 * We flush the register file to the stack by doing a kernel call.
 * This is necessary to ensure that the registers we want to
 * pick up are stored on the stack, and that subsequent restores
 * will function correctly.
 *
 * sp, fp, and %i7, the caller's return address, are all restored
 * to the values they had at the time of the call to setjmp().  All
 * other locals, ins and outs are set to potentially random values
 * (as per the man page).  This is sufficient to permit the correct
 * operation of normal code.
 *
 * Actually, the above description is not quite correct.  If the routine
 * that called setjmp() has not altered the sp value of their frame we
 * will restore the remaining locals and ins to the values these
 * registers had in the this frame at the time of the call to longjmp()
 * (not setjmp()!).  This is intended to help compilers, typically not
 * C compilers, that have some registers assigned to fixed purposes,
 * and that only alter the values of these registers on function entry
 * and exit.
 *
 * Since a C routine could call setjmp() followed by alloca() and thus
 * alter the sp this feature will typically not be helpful for a C
 * compiler.
 *
 * Note also that because the caller of a routine compiled "flat" (without
 * register windows) assumes that their ins and locals are preserved,
 * routines that call setjmp() must not be flat.
 */
        ENTRY(longjmp)
        ta      ST_FLUSH_WINDOWS        ! flush all reg windows to the stack.
        ld      [%o0 + JB_SP], %o2      ! sp in %o2 until safe to puke there
        ldd     [%o2 + (0*8)], %l0      ! restore locals and ins if we can
        ldd     [%o2 + (1*8)], %l2
        ldd     [%o2 + (2*8)], %l4
        ldd     [%o2 + (3*8)], %l6
        ldd     [%o2 + (4*8)], %i0
        ldd     [%o2 + (5*8)], %i2
        ldd     [%o2 + (6*8)], %i4
        ld      [%o0 + JB_FP], %fp      ! restore fp
        mov     %o2, %sp                ! restore sp
        ld      [%o0 + JB_FLAGS], %o2
        btst    JB_CLEARLINK, %o2       ! test JB_CLEARLINK flag
        bne,a,pt %icc, 1f
        clr     [%g7 + UL_SIGLINK]      ! if set, clear ul_siglink
1:
        ld      [%o0 + JB_I7], %i7      ! restore %i7
        ld      [%o0 + JB_PC], %o3      ! get new return pc
        tst     %o1                     ! is return value 0?
        bnz     1f                      ! no - leave it alone
        sub     %o3, 8, %o7             ! normalize return (for adb) (dly slot)
        mov     1, %o1                  ! yes - set it to one
1:
        retl
        mov     %o1, %o0                ! return (val)

        SET_SIZE(longjmp)