705 lines
14 KiB
C
705 lines
14 KiB
C
/*
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* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
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* See the copyright notice in the ACK home directory, in the file "Copyright".
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*
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* Author: Ceriel J.H. Jacobs
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*/
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/* D E S I G N A T O R E V A L U A T I O N */
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/* $Id$ */
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/* Code generation for designators.
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This file contains some routines that generate code common to address
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as well as value computations, and leave a description in a "desig"
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structure. It also contains routines to load an address, load a value
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or perform a store.
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*/
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#include "debug.h"
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#include <em_arith.h>
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#include <em_label.h>
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#include <em_code.h>
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#include <assert.h>
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#include <alloc.h>
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#include "type.h"
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#include "LLlex.h"
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#include "def.h"
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#include "scope.h"
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#include "desig.h"
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#include "node.h"
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#include "warning.h"
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#include "walk.h"
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#include "squeeze.h"
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extern int proclevel;
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extern arith NewPtr();
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extern char options[];
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int
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WordOrDouble(ds, size)
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t_desig *ds;
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arith size;
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{
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/* Check if designator is suitable for word or double-word
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operation
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*/
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if ((int) (ds->dsg_offset) % word_align == 0) {
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if (size == word_size) return 1;
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if (size == dword_size) return 2;
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}
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return 0;
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}
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LOL(offset, size)
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arith offset, size;
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{
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if (size == word_size) {
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C_lol(offset);
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}
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else if (size == dword_size) {
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C_ldl(offset);
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}
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else {
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C_lal(offset);
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C_loi(size);
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}
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}
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STL(offset, size)
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arith offset, size;
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{
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if (size == word_size) {
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C_stl(offset);
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}
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else if (size == dword_size) {
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C_sdl(offset);
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}
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else {
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C_lal(offset);
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C_sti(size);
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}
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}
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int
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DoLoad(ds, size)
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register t_desig *ds;
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arith size;
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{
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/* Try to load designator with word or double-word operation.
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Return 0 if not done
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*/
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switch (WordOrDouble(ds, size)) {
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default:
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return 0;
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case 1:
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if (ds->dsg_name) {
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C_loe_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_lol(ds->dsg_offset);
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break;
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case 2:
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if (ds->dsg_name) {
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C_lde_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_ldl(ds->dsg_offset);
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break;
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}
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return 1;
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}
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int
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DoStore(ds, size)
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register t_desig *ds;
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arith size;
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{
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/* Try to store designator with word or double-word operation.
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Return 0 if not done
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*/
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switch (WordOrDouble(ds, size)) {
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default:
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return 0;
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case 1:
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if (ds->dsg_name) {
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C_ste_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_stl(ds->dsg_offset);
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break;
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case 2:
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if (ds->dsg_name) {
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C_sde_dnam(ds->dsg_name, ds->dsg_offset);
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}
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else C_sdl(ds->dsg_offset);
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break;
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}
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return 1;
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}
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/* Return 1 if the type indicated by tp has a size that is a
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multiple of the word_size and is also word_aligned
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*/
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#define word_multiple(tp) \
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( (int)(tp->tp_size) % (int)word_size == 0 && \
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tp->tp_align >= word_align)
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/* Return 1 if the type indicated by tp has a size that is a proper
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dividor of the word_size, and has alignment >= size or
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alignment >= word_align
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*/
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#define word_dividor(tp) \
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( tp->tp_size < word_size && \
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(int)word_size % (int)(tp->tp_size) == 0 && \
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(tp->tp_align >= word_align || \
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tp->tp_align >= (int)(tp->tp_size)))
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#define USE_LOI_STI 0
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#define USE_LOS_STS 1
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#define USE_LOAD_STORE 2
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#define USE_BLM 3 /* like USE_LOI_STI, but more restricted:
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multiple of word_size only
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*/
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STATIC int
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suitable_move(tp)
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register t_type *tp;
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{
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/* Find out how to load or store the value indicated by "ds".
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There are four ways:
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- suitable for BLM/LOI/STI
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- suitable for LOI/STI
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- suitable for LOS/STS/BLS
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- suitable for calls to load/store/blockmove
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*/
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if (! word_multiple(tp)) {
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if (word_dividor(tp)) return USE_LOI_STI;
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return USE_LOAD_STORE;
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}
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if (! fit(tp->tp_size, (int) word_size)) return USE_LOS_STS;
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return USE_BLM;
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}
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CodeValue(ds, tp)
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register t_desig *ds;
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register t_type *tp;
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{
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/* Generate code to load the value of the designator described
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in "ds".
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*/
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arith sz;
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switch(ds->dsg_kind) {
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case DSG_LOADED:
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break;
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case DSG_FIXED:
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if (DoLoad(ds, tp->tp_size)) break;
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/* Fall through */
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case DSG_PLOADED:
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case DSG_PFIXED:
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switch (suitable_move(tp)) {
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case USE_BLM:
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case USE_LOI_STI:
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#ifndef SQUEEZE
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CodeAddress(ds);
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C_loi(tp->tp_size);
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break;
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#endif
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case USE_LOS_STS:
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CodeAddress(ds);
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CodeConst(tp->tp_size, (int)pointer_size);
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C_los(pointer_size);
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break;
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case USE_LOAD_STORE:
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sz = WA(tp->tp_size);
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if (ds->dsg_kind != DSG_PFIXED) {
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arith tmp = NewPtr();
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CodeAddress(ds);
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STL(tmp, pointer_size);
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CodeConst(-sz, (int) pointer_size);
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C_ass(pointer_size);
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LOL(tmp, pointer_size);
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FreePtr(tmp);
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}
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else {
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CodeConst(-sz, (int) pointer_size);
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C_ass(pointer_size);
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CodeAddress(ds);
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}
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CodeConst(tp->tp_size, (int) pointer_size);
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CAL("load", (int)pointer_size + (int)pointer_size);
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break;
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}
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break;
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case DSG_INDEXED:
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C_lar(word_size);
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break;
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default:
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crash("(CodeValue)");
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}
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ds->dsg_kind = DSG_LOADED;
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}
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ChkForFOR(nd)
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register t_node *nd;
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{
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/* Check for an assignment to a FOR-loop control variable
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*/
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if (nd->nd_class == Def) {
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register t_def *df = nd->nd_def;
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if (df->df_flags & D_FORLOOP) {
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node_warning(nd,
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W_ORDINARY,
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"assignment to FOR-loop control variable");
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df->df_flags &= ~D_FORLOOP;
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/* only procude warning once */
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}
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}
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}
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CodeStore(ds, tp)
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register t_desig *ds;
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register t_type *tp;
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{
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/* Generate code to store the value on the stack in the designator
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described in "ds"
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*/
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switch(ds->dsg_kind) {
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case DSG_FIXED:
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if (DoStore(ds, tp->tp_size)) break;
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/* Fall through */
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case DSG_PLOADED:
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case DSG_PFIXED:
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CodeAddress(ds);
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switch (suitable_move(tp)) {
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case USE_BLM:
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case USE_LOI_STI:
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#ifndef SQUEEZE
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C_sti(tp->tp_size);
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break;
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#endif
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case USE_LOS_STS:
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CodeConst(tp->tp_size, (int) pointer_size);
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C_sts(pointer_size);
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break;
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case USE_LOAD_STORE:
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CodeConst(tp->tp_size, (int) pointer_size);
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C_cal("store");
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CodeConst(pointer_size + pointer_size + WA(tp->tp_size),
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(int) pointer_size);
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C_ass(pointer_size);
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break;
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}
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break;
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case DSG_INDEXED:
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C_sar(word_size);
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break;
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default:
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crash("(CodeStore)");
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}
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ds->dsg_kind = DSG_INIT;
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}
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CodeCopy(lhs, rhs, sz, psize)
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register t_desig *lhs, *rhs;
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arith sz, *psize;
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{
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/* Do part of a copy, which is assumed to be "reasonable",
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so that it can be done with LOI/STI or BLM.
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*/
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t_desig l, r;
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l = *lhs; r = *rhs;
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*psize -= sz;
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lhs->dsg_offset += sz;
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rhs->dsg_offset += sz;
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CodeAddress(&r);
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if (sz <= dword_size) {
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C_loi(sz);
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CodeAddress(&l);
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C_sti(sz);
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}
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else {
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CodeAddress(&l);
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C_blm(sz);
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}
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}
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t_desig null_desig;
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CodeMove(rhs, left, rtp)
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register t_desig *rhs;
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register t_node *left;
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t_type *rtp;
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{
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/* Generate code for an assignment. Testing of type
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compatibility and the like is already done.
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Go through some (considerable) trouble to see if a BLM can be
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generated.
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*/
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t_desig lhs;
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register t_type *tp = left->nd_type;
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int loadedflag = 0;
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lhs = null_desig;
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ChkForFOR(left);
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switch(rhs->dsg_kind) {
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case DSG_LOADED:
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CodeDesig(left, &lhs);
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if (rtp->tp_fund == T_STRING) {
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/* size of a string literal fits in an
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int of size word_size
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*/
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CodeAddress(&lhs);
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C_loc(rtp->tp_size);
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C_loc(tp->tp_size);
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CAL("StringAssign", (int)pointer_size + (int)pointer_size + (int)dword_size);
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break;
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}
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CodeStore(&lhs, tp);
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break;
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case DSG_FIXED:
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CodeDesig(left, &lhs);
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if (lhs.dsg_kind == DSG_FIXED &&
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fit(tp->tp_size, (int) word_size) &&
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(int) (lhs.dsg_offset) % word_align ==
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(int) (rhs->dsg_offset) % word_align) {
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register int sz = 1;
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arith size = tp->tp_size;
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while (size && sz < word_align) {
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/* First copy up to word-aligned
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boundaries
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*/
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if (!((int)(lhs.dsg_offset)%(sz+sz))) {
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sz += sz;
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}
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else CodeCopy(&lhs, rhs, (arith) sz, &size);
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}
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/* Now copy the bulk
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*/
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sz = (int) size % (int) word_size;
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size -= sz;
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CodeCopy(&lhs, rhs, size, &size);
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size = sz;
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sz = word_size;
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while (size) {
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/* And then copy remaining parts
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*/
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sz >>= 1;
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if (size >= sz) {
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CodeCopy(&lhs, rhs, (arith) sz, &size);
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}
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}
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break;
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}
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CodeAddress(&lhs);
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loadedflag = 1;
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/* Fall through */
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case DSG_PLOADED:
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case DSG_PFIXED:
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assert(! loadedflag || rhs->dsg_kind == DSG_FIXED);
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CodeAddress(rhs);
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if (loadedflag) {
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C_exg(pointer_size);
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}
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else {
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CodeDesig(left, &lhs);
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CodeAddress(&lhs);
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}
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switch (suitable_move(tp)) {
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case USE_BLM:
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#ifndef SQUEEZE
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C_blm(tp->tp_size);
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break;
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#endif
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case USE_LOS_STS:
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CodeConst(tp->tp_size, (int) pointer_size);
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C_bls(pointer_size);
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break;
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case USE_LOAD_STORE:
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case USE_LOI_STI:
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CodeConst(tp->tp_size, (int) pointer_size);
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CAL("blockmove", 3 * (int)pointer_size);
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break;
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}
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break;
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default:
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crash("CodeMove");
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}
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}
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CodeAddress(ds)
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register t_desig *ds;
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{
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/* Generate code to load the address of the designator described
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in "ds"
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*/
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switch(ds->dsg_kind) {
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case DSG_PLOADED:
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if (ds->dsg_offset) {
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C_adp(ds->dsg_offset);
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}
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break;
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case DSG_FIXED:
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if (ds->dsg_name) {
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C_lae_dnam(ds->dsg_name, ds->dsg_offset);
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break;
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}
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C_lal(ds->dsg_offset);
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if (ds->dsg_def) ds->dsg_def->df_flags |= D_NOREG;
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break;
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case DSG_PFIXED:
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if (! DoLoad(ds, pointer_size)) {
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assert(0);
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}
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break;
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case DSG_INDEXED:
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C_aar(word_size);
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break;
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default:
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crash("(CodeAddress)");
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}
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ds->dsg_offset = 0;
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ds->dsg_kind = DSG_PLOADED;
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}
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CodeFieldDesig(df, ds)
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register t_def *df;
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register t_desig *ds;
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{
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/* Generate code for a field designator. Only the code common for
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address as well as value computation is generated, and the
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resulting information on where to find the designator is placed
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in "ds". "df" indicates the definition of the field.
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*/
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if (ds->dsg_kind == DSG_INIT) {
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/* In a WITH statement. We must find the designator in the
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WITH statement, and act as if the field is a selection
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of this designator.
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So, first find the right WITH statement, which is the
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first one of the proper record type, which is
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recognized by its scope indication.
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*/
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register struct withdesig *wds = WithDesigs;
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assert(wds != 0);
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while (wds->w_scope != df->df_scope) {
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wds = wds->w_next;
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assert(wds != 0);
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}
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/* Found it. Now, act like it was a selection.
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*/
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*ds = wds->w_desig;
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wds->w_flags |= df->df_flags;
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assert(ds->dsg_kind == DSG_PFIXED);
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}
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switch(ds->dsg_kind) {
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case DSG_PLOADED:
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case DSG_FIXED:
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ds->dsg_offset += df->fld_off;
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break;
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case DSG_PFIXED:
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case DSG_INDEXED:
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CodeAddress(ds);
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ds->dsg_kind = DSG_PLOADED;
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ds->dsg_offset = df->fld_off;
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break;
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default:
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crash("(CodeFieldDesig)");
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}
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}
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CodeVarDesig(df, ds)
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register t_def *df;
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register t_desig *ds;
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{
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/* Generate code for a variable represented by a "def" structure.
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Of course, there are numerous cases: the variable is local,
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it is a value parameter, it is a var parameter, it is one of
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those of an enclosing procedure, or it is global.
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*/
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register t_scope *sc = df->df_scope;
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int difflevel;
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/* Selections from a module are handled earlier, when identifying
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the variable, so ...
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*/
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assert(ds->dsg_kind == DSG_INIT);
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if (df->df_flags & D_ADDRGIVEN) {
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/* the programmer specified an address in the declaration of
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the variable. Generate code to push the address.
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*/
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CodeConst(df->var_off, (int) pointer_size);
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ds->dsg_kind = DSG_PLOADED;
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ds->dsg_offset = 0;
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return;
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}
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if (df->var_name) {
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/* this variable has been given a name, so it is global.
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It is directly accessible.
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*/
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ds->dsg_name = df->var_name;
|
|
ds->dsg_offset = 0;
|
|
ds->dsg_kind = DSG_FIXED;
|
|
return;
|
|
}
|
|
|
|
if ((difflevel = proclevel - sc->sc_level) != 0) {
|
|
/* the variable is local to a statically enclosing procedure.
|
|
*/
|
|
assert(difflevel > 0);
|
|
|
|
df->df_flags |= D_NOREG;
|
|
if (df->df_flags & (D_VARPAR|D_VALPAR)) {
|
|
/* value or var parameter
|
|
*/
|
|
C_lxa((arith) difflevel);
|
|
if ((df->df_flags & D_VARPAR) ||
|
|
IsConformantArray(df->df_type)) {
|
|
/* var parameter or conformant array.
|
|
The address is passed.
|
|
*/
|
|
C_adp(df->var_off);
|
|
C_loi(pointer_size);
|
|
ds->dsg_offset = 0;
|
|
ds->dsg_kind = DSG_PLOADED;
|
|
return;
|
|
}
|
|
}
|
|
else C_lxl((arith) difflevel);
|
|
ds->dsg_kind = DSG_PLOADED;
|
|
ds->dsg_offset = df->var_off;
|
|
return;
|
|
}
|
|
|
|
/* Now, finally, we have a local variable or a local parameter
|
|
*/
|
|
if ((df->df_flags & D_VARPAR) ||
|
|
IsConformantArray(df->df_type)) {
|
|
/* a var parameter; address directly accessible.
|
|
*/
|
|
ds->dsg_kind = DSG_PFIXED;
|
|
}
|
|
else ds->dsg_kind = DSG_FIXED;
|
|
ds->dsg_offset = df->var_off;
|
|
ds->dsg_def = df;
|
|
}
|
|
|
|
CodeDesig(nd, ds)
|
|
register t_node *nd;
|
|
register t_desig *ds;
|
|
{
|
|
/* Generate code for a designator. Use divide and conquer
|
|
principle
|
|
*/
|
|
register t_def *df;
|
|
|
|
switch(nd->nd_class) { /* Divide */
|
|
case Def:
|
|
df = nd->nd_def;
|
|
if (nd->nd_NEXT) CodeDesig(nd->nd_NEXT, ds);
|
|
|
|
switch(df->df_kind) {
|
|
case D_FIELD:
|
|
CodeFieldDesig(df, ds);
|
|
break;
|
|
|
|
case D_VARIABLE:
|
|
CodeVarDesig(df, ds);
|
|
break;
|
|
|
|
default:
|
|
crash("(CodeDesig) Def");
|
|
}
|
|
break;
|
|
|
|
case Arrsel:
|
|
assert(nd->nd_symb == '[' || nd->nd_symb == ',');
|
|
|
|
CodeDesig(nd->nd_LEFT, ds);
|
|
CodeAddress(ds);
|
|
CodePExpr(nd->nd_RIGHT);
|
|
nd = nd->nd_LEFT;
|
|
|
|
/* Now load address of descriptor
|
|
*/
|
|
if (IsConformantArray(nd->nd_type)) {
|
|
arith off;
|
|
assert(nd->nd_class == Def);
|
|
|
|
df = nd->nd_def;
|
|
off = df->var_off + pointer_size;
|
|
if (proclevel > df->df_scope->sc_level) {
|
|
C_lxa((arith) (proclevel - df->df_scope->sc_level));
|
|
C_adp(off);
|
|
}
|
|
else C_lal(off);
|
|
}
|
|
else {
|
|
C_loc(nd->nd_type->arr_low);
|
|
C_sbu(int_size);
|
|
c_lae_dlb(nd->nd_type->arr_descr);
|
|
}
|
|
if (options['A']) {
|
|
C_cal("rcka");
|
|
}
|
|
ds->dsg_kind = DSG_INDEXED;
|
|
break;
|
|
|
|
case Arrow:
|
|
assert(nd->nd_symb == '^');
|
|
|
|
nd = nd->nd_RIGHT;
|
|
CodeDesig(nd, ds);
|
|
switch(ds->dsg_kind) {
|
|
case DSG_LOADED:
|
|
ds->dsg_kind = DSG_PLOADED;
|
|
break;
|
|
|
|
case DSG_INDEXED:
|
|
case DSG_PLOADED:
|
|
case DSG_PFIXED:
|
|
CodeValue(ds, nd->nd_type);
|
|
ds->dsg_kind = DSG_PLOADED;
|
|
ds->dsg_offset = 0;
|
|
break;
|
|
|
|
case DSG_FIXED:
|
|
ds->dsg_kind = DSG_PFIXED;
|
|
break;
|
|
|
|
default:
|
|
crash("(CodeDesig) Uoper");
|
|
}
|
|
break;
|
|
|
|
default:
|
|
crash("(CodeDesig) class");
|
|
}
|
|
}
|