[m-dev.] for review: new method of handling failures, part 2 of 6

[Fergus Henderson]

On 02-Jul-1998, Zoltan Somogyi <zs at cs.mu.OZ.AU> wrote:
> 
> <continuing the new code_info.m>
...
> 	% XXX We could use the sanity checking mechanism...
> code_info__clear_all_registers -->
> 	code_info__get_exprn_info(Exprn0),
> 	{ code_exprn__clobber_regs([], Exprn0, Exprn) },
> 	code_info__set_exprn_info(Exprn).

I don't understand the comment.

> %---------------------------------------------------------------------------%
> 
> 	% Submodule for managing stack slots.
> 
> 	% The det stack frame is organized as follows.
> 	%
> 	%		... unused ...
> 	%	sp --->	<first unused slot>
> 	%		<space for local var 1>
> 	%		... local vars ...
> 	%		<space for local var n>
> 	%		<space for temporary reg save 1>
> 	%		... temporary reg saves ...
> 	%		<space for temporary reg save n>

It is?  Are you sure??

I thought it was

 	%		... unused ...
 	%	sp --->	<first unused slot>
 	%		<space for succip>
			...

Did that change?
		
> 	% `code_info__num_stackslots' counts the number of slots reserved
> 	% for saving local variables. XXX

Please explain the XXX.

> 	% The variable part of the nondet stack is organized in the same way
> 	% as the det stack (but the nondet stack also contains several other
> 	% fixed fields.)

Is this true for the saved succip slot?

> %---------------------------------------------------------------------------%
> 
> 	% Values of this type hold information about stack frames that is
> 	% generated when generating prologs and is used in generating epilogs
> 	% and when massaging the code generated for the procedure.
> 
> :- type frame_info	--->	frame(
> 					int, 	    % Number of slots in frame.
> 
> 					maybe(int), % Slot number of succip
> 						    % if succip is present
> 						    % in a general slot.
> 
> 					bool	    % Is this the frame of a
> 						    % model_non proc defined
> 						    % via pragma C code?
> 				).

Please use the layout recommended in our Mercury coding guidelines:

	:- type foo
		--->	foo(
				...
			).

(This layout leaves more room for comments.)

[... to be continued ...]

-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.