Newsgroups: comp.lang.asm370
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From: phil@ux1.cso.uiuc.edu (Phil Howard KA9WGN)
Subject: Re: disabling CTRL-BREAK (dos)
Message-ID: <1991May30.000520.1375@ux1.cso.uiuc.edu>
Organization: University of Illinois at Urbana
References: <9105250259.AA11782@ucbvax.Berkeley.EDU> <91149.115927BRYAN@wvnvm.wvnet.edu>
Distribution: inet
Date: Thu, 30 May 1991 00:05:20 GMT
Lines: 20

Jerry Bryan <BRYAN@wvnvm.wvnet.edu> writes:

>The old Waterloo WATBOL compiler used invalid opcodes on purpose (trapping
>them with SPIE macro) to effect paragraph tracing.  One of the opcodes
>they chose invoked the APL microcode assist on a 370/148 rather than
>generating on operation exception.  We therefore
>found the problem of why tracing wouldn't work by reading the 148's
>microcode.

If the compiler is generating the code, why can't it simply generate a
branch to a trace subroutine.

When I need tracing, I use a set of trace macros I write.  Works great and
does not affect any registers.  The only requirement is that there be a
base register in effect.
-- 
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