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[unix-history] / usr / src / libc / sys / reset.s

# C library -- reset, setexit

#       reset(x)
# will generate a "return" from
# the last call to
#       setexit()
# by restoring r6 - r12, ap, fp
# and doing a return.
# The returned value is x; on the original
# call the returned value is 0.
#
# useful for going back to the main loop
# after a horrible error in a lowlevel
# routine.

.globl  _setexit
.globl  _reset

       .align  1
_setexit:
       .word   0x0000
       movab   setsav,r0
       movq    r6,(r0)+
       movq    r8,(r0)+
       movq    r10,(r0)+
       movq    8(fp),(r0)+             # ap, fp
       movab   4(ap),(r0)+             # sp
       movl    16(fp),(r0)             # pc
       clrl    r0
       ret

       .align  1
_reset:
       .word   0x0000
       movl    4(ap),r0        # returned value
       movab   setsav,r1
       movq    (r1)+,r6
       movq    (r1)+,r8
       movq    (r1)+,r10
       movq    (r1)+,r12
       movl    (r1)+,sp
       jmp     *(r1)

       .data
setsav: .space  10*4