usr/src/lib/libpc/SETRACE.s

# Copyright (c) 1979 Regents of the University of California
#
# sccsid[] = "@(#)SETRACE.s 1.1 10/29/80";
#
# set trace bit in return frame of calling routine
# this will cause core dump at point of return
# unless running a debugger, in which case a breakpoint
# will occur at the error point
#
        .globl  _SETRACE
_SETRACE:
        .word   0
        movl    FP(fp),r0       #r0 has ptr to callers frame
        bisl2   $0x10,PSW(r0)   #set trace bit
        ret