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/*
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Crown Copyright (c) 1997
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This TenDRA(r) Computer Program is subject to Copyright
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owned by the United Kingdom Secretary of State for Defence
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acting through the Defence Evaluation and Research Agency
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(DERA). It is made available to Recipients with a
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royalty-free licence for its use, reproduction, transfer
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to other parties and amendment for any purpose not excluding
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product development provided that any such use et cetera
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shall be deemed to be acceptance of the following conditions:-
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(1) Its Recipients shall ensure that this Notice is
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reproduced upon any copies or amended versions of it;
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(2) Any amended version of it shall be clearly marked to
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show both the nature of and the organisation responsible
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for the relevant amendment or amendments;
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(3) Its onward transfer from a recipient to another
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party shall be deemed to be that party's acceptance of
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these conditions;
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(4) DERA gives no warranty or assurance as to its
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quality or suitability for any purpose and DERA accepts
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no liability whatsoever in relation to any use to which
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it may be put.
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*/
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/**********************************************************************
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$Author: release $
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$Date: 1998/01/17 15:56:05 $
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$Revision: 1.1.1.1 $
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$Log: guard.c,v $
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* Revision 1.1.1.1 1998/01/17 15:56:05 release
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* First version to be checked into rolling release.
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*
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* Revision 1.3 1995/09/12 10:59:23 currie
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* gcc pedanttry
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*
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* Revision 1.2 1995/08/16 16:06:42 currie
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* Shortened some .h names
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*
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* Revision 1.1 1995/04/13 09:08:06 currie
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* Initial revision
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*
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***********************************************************************/
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/****************************************************************
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guard.c
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These routines protect registers from future use. The type
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involved is space which consists of two long ints with bit patterns
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taken to represent usage of temporary fixed and floating
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point registers. These bits are used in the procedure
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getregs which understands a clear bit to mean that the corresponding
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register is free for use.
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The procedures are widely used in make_code which may use
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getreg to choose a register to contain the result of an expression.
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If this expression is the first operand of a binary operation (say) then the register
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is guarded, producing another space which will be used by make_code for the
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second operand.
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******************************************************************/
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#include "config.h"
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#include "procrectypes.h"
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#include "addrtypes.h"
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#include "basicread.h"
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#include "guard.h"
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/*******************************************************************
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The integer parameter to procedures guardreg and guardfreg
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is taken to be a register which needs to be protected. For floating point
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registers a factor of 2 is involved. The corresponding bit in the appropriate field of the
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space i.e fixed or float, is therefore set.
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********************************************************************/
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space guardreg
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PROTO_N ( (r, sp) )
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PROTO_T ( int r X space sp )
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{
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if ((r >= 2 && r <= 15) || (r >= 24 && r <= 25) || r==31) {
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/* r is a fixed point t reg */
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sp.fixed |= (1 << r);
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} /* set bit in the fixed field of sp */
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return sp;
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}
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space guardfreg
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PROTO_N ( (r, sp) )
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PROTO_T ( int r X space sp )
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{
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if (r<=9) {
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/* r is a floating point t reg */
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sp.flt |= (1 << r);
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} /* set bit in the flt field of sp */
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return sp;
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}
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/********************************************************************
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The procedure guard may also protect a register involved in
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addressing depending on the value of the parameter of type where. This is a
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union of a fixpnt reg , a float reg and an instore value. In the latter case the
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register involved in the addressing can be deduced from the base field of the
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instore value. These types are defined in addressingtypes.h.
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*********************************************************************/
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space guard
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PROTO_N ( (w, sp) )
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PROTO_T ( where w X space sp )
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{
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switch (w.answhere.discrim) {
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case inreg:
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{
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int r = regalt (w.answhere);
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if ((r >= 2 && r <= 15) || (r >= 24 && r <= 25) || r==31) {
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sp.fixed |= (1 << r);
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} /* guard reg */
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return sp;
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}
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case infreg:
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{
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int r = fregalt (w.answhere).fr;
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if (r<=9) {
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sp.flt |= (1 << r);
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} /* guard freg */
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return sp;
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}
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case notinreg:
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{
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int r = insalt (w.answhere).b.base;
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if ((r >= 2 && r <= 15) || (r >= 24 && r <= 25) || r==31) {
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sp.fixed |= (1 << r);
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}
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/* guard fixed point t reg used as base of address */
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return sp;
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}
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default: {
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failer ("Guard ? reg ");
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}
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}
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return sp;
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}
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