usr/src/lib/libc/tahoe/gen/setjmp.s

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 * This code is derived from software contributed to Berkeley by
 * Computer Consoles Inc.
 */

#if defined(LIBC_SCCS) && !defined(lint)
        .asciz "@(#)setjmp.s    1.5 (Berkeley) %G%"
#endif /* LIBC_SCCS and not lint */

/*
 * C library -- setjmp, longjmp
 *
 *      longjmp(a,v)
 * will generate a "return(v)" from
 * the last call to
 *      setjmp(a)
 * by restoring registers from the stack,
 * previous signal mask, and doing a return.
 */

#include "DEFS.h"

ENTRY(setjmp, R6)
        movl    4(fp),r6                # construct sigcontext
        movab   -8(sp),sp               # space for current struct sigstack
        pushal  (sp)                    # get current values
        pushl   $0                      # no new values
        callf   $16,_sigstack           # pop args plus signal stack value
        movl    (sp)+,(r6)              # save onsigstack status of caller
        pushl   $0
        callf   $8,_sigblock            # get signal mask
        movl    r0,4(r6)                # save signal mask of caller
        addl3   $8,fp,8(r6)             # save stack pointer of caller
        movl    (fp),12(r6)             # save frame pointer of caller
        movl    -8(fp),20(r6)           # save pc of caller
        movpsl  24(r6)                  # save psl of caller
        clrl    r0
        ret

ENTRY(longjmp, 0)
        movl    8(fp),r0                # return(v)
        movl    4(fp),r1                # fetch buffer
        tstl    12(r1)
        beql    botch
loop:
        cmpl    12(r1),(fp)
        beql    done
        blssu   botch
        movl    $loop,-8(fp)
        ret                             # pop another frame

done:
        cmpb    *-8(fp),reiins          # returning to an "rei"?
        bneq    1f
        movab   3f,-8(fp)               # do return w/ psl-pc pop
        brw     2f
1:
        movab   4f,-8(fp)               # do standard return
2:
        ret                             # unwind stack before signals enabled
3:
        addl2   $8,sp                   # compensate for PSL-PC push
4:
        pushl   r1                      # pointer to sigcontext
        callf   $4,_sigreturn           # restore previous context
                                        # we should never return

botch:
        callf   $4,_longjmperror
        halt

        .data
reiins: rei