572 lines
12 KiB
C
572 lines
12 KiB
C
/* D E S I G N A T O R E V A L U A T I O N */
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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 "type.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 "LLlex.h"
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#include "node.h"
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extern int proclevel;
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struct desig InitDesig = {DSG_INIT, 0, 0};
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STATIC int
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properly(ds, size, al)
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register struct desig *ds;
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arith size;
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{
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/* Check if it is allowed to load or store the value indicated
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by "ds" with LOI/STI.
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- if the size is not either a multiple or a dividor of the
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wordsize, then not.
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- if the alignment is at least "word" then OK.
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- if size is dividor of word_size and alignment >= size then OK.
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- otherwise check alignment of address. This can only be done
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with DSG_FIXED.
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*/
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arith szmodword = size % word_size; /* 0 if multiple of wordsize */
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arith wordmodsz = word_size % size; /* 0 if dividor of wordsize */
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if (szmodword && wordmodsz) return 0;
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if (al >= word_size) return 1;
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if (szmodword && al >= szmodword) return 1;
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return ds->dsg_kind == DSG_FIXED &&
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((! szmodword && ds->dsg_offset % word_size == 0) ||
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(! wordmodsz && ds->dsg_offset % size == 0));
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}
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CodeValue(ds, size, al)
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register struct desig *ds;
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arith size;
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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 tmp = 0;
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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 (ds->dsg_offset % word_size == 0) {
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if (size == word_size) {
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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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}
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if (size == dword_size) {
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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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}
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/* Fall through */
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case DSG_PLOADED:
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case DSG_PFIXED:
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if (properly(ds, size, al)) {
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CodeAddress(ds);
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C_loi(size);
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break;
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}
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if (ds->dsg_kind == DSG_PLOADED) {
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tmp = NewPtr();
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C_stl(tmp);
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}
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C_asp(-WA(size));
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if (!tmp) CodeAddress(ds);
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else {
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C_lol(tmp);
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FreePtr(tmp);
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}
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C_loc(size);
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C_cal("_load");
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C_asp(2 * word_size);
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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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CodeStore(ds, size, al)
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register struct desig *ds;
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arith size;
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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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struct desig save;
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save = *ds;
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switch(ds->dsg_kind) {
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case DSG_FIXED:
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if (ds->dsg_offset % word_size == 0) {
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if (size == word_size) {
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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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}
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if (size == dword_size) {
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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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}
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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(&save);
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if (properly(ds, size, al)) {
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C_sti(size);
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break;
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}
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C_loc(size);
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C_cal("_store");
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C_asp(2 * word_size + WA(size));
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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 struct desig *lhs, *rhs;
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arith sz, *psize;
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{
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struct 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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C_loi(sz);
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CodeAddress(&l);
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C_sti(sz);
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}
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CodeMove(rhs, left, rtp)
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register struct desig *rhs;
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register struct node *left;
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struct type *rtp;
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{
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struct desig dsl;
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register struct desig *lhs = &dsl;
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register struct type *tp = left->nd_type;
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int loadedflag = 0;
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dsl = InitDesig;
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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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switch(rhs->dsg_kind) {
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case DSG_LOADED:
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CodeDesig(left, lhs);
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CodeAddress(lhs);
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if (rtp->tp_fund == T_STRING) {
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C_loc(rtp->tp_size);
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C_loc(tp->tp_size);
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C_cal("_StringAssign");
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C_asp(word_size << 2);
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return;
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}
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CodeStore(lhs, tp->tp_size, tp->tp_align);
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return;
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case DSG_PLOADED:
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case DSG_PFIXED:
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CodeAddress(rhs);
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if (tp->tp_size % word_size == 0 && tp->tp_align >= word_size) {
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CodeDesig(left, lhs);
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CodeAddress(lhs);
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C_blm(tp->tp_size);
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return;
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}
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CodeValue(rhs, tp->tp_size, tp->tp_align);
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CodeDStore(left);
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return;
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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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lhs->dsg_offset % word_size ==
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rhs->dsg_offset % word_size) {
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register arith sz;
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arith size = tp->tp_size;
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while (size && (sz = (lhs->dsg_offset % word_size))) {
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/* First copy up to word-aligned
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boundaries
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*/
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if (sz < 0) sz = -sz; /* bloody '%' */
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while (word_size % sz) sz--;
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CodeCopy(lhs, rhs, sz, &size);
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}
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if (size > 3*dword_size) {
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/* Do a block move
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*/
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struct desig l, r;
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sz = (size / word_size) * word_size;
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l = *lhs; r = *rhs;
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CodeAddress(&r);
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CodeAddress(&l);
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C_blm(sz);
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rhs->dsg_offset += sz;
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lhs->dsg_offset += sz;
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size -= sz;
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}
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else for (sz = dword_size; sz; sz -= word_size) {
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while (size >= sz) {
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/* Then copy dwords, words.
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Depend on peephole optimizer
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*/
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CodeCopy(lhs, rhs, sz, &size);
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}
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}
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sz = word_size;
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while (size && --sz) {
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/* And then copy remaining parts
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*/
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while (word_size % sz) sz--;
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while (size >= sz) {
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CodeCopy(lhs, rhs, sz, &size);
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}
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}
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return;
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}
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if (lhs->dsg_kind == DSG_PLOADED ||
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lhs->dsg_kind == DSG_INDEXED) {
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CodeAddress(lhs);
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loadedflag = 1;
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}
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if (tp->tp_size % word_size == 0 && tp->tp_align >= word_size) {
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CodeAddress(rhs);
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if (loadedflag) C_exg(pointer_size);
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else CodeAddress(lhs);
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C_blm(tp->tp_size);
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return;
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}
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{
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arith tmp;
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if (loadedflag) {
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tmp = NewPtr();
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lhs->dsg_offset = tmp;
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lhs->dsg_name = 0;
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lhs->dsg_kind = DSG_PFIXED;
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C_stl(tmp); /* address of lhs */
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}
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CodeValue(rhs, tp->tp_size, tp->tp_align);
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CodeStore(lhs, tp->tp_size, tp->tp_align);
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if (loadedflag) FreePtr(tmp);
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return;
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}
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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 struct 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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break;
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case DSG_PFIXED:
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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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break;
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}
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C_lol(ds->dsg_offset);
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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 struct def *df;
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register struct 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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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 struct def *df;
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register struct 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 struct scope *sc = df->df_scope;
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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->var_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, 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;
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ds->dsg_offset = 0;
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ds->dsg_kind = DSG_FIXED;
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return;
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}
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if (sc->sc_level != proclevel) {
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/* the variable is local to a statically enclosing procedure.
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*/
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assert(proclevel > sc->sc_level);
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df->df_flags |= D_NOREG;
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if (df->df_flags & (D_VARPAR|D_VALPAR)) {
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/* value or var parameter
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*/
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C_lxa((arith) (proclevel - sc->sc_level));
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if ((df->df_flags & D_VARPAR) ||
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IsConformantArray(df->df_type)) {
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/* var parameter or conformant array.
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For conformant array's, the address is
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passed.
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*/
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C_adp(df->var_off);
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C_loi(pointer_size);
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ds->dsg_offset = 0;
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ds->dsg_kind = DSG_PLOADED;
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return;
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}
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}
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else C_lxl((arith) (proclevel - sc->sc_level));
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ds->dsg_kind = DSG_PLOADED;
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ds->dsg_offset = df->var_off;
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return;
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}
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/* Now, finally, we have a local variable or a local parameter
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*/
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if ((df->df_flags & D_VARPAR) || IsConformantArray(df->df_type)) {
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/* a var parameter; address directly accessible.
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*/
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ds->dsg_kind = DSG_PFIXED;
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}
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else ds->dsg_kind = DSG_FIXED;
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ds->dsg_offset =df->var_off;
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}
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CodeDesig(nd, ds)
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register struct node *nd;
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register struct desig *ds;
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{
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/* Generate code for a designator. Use divide and conquer
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principle
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*/
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register struct def *df;
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switch(nd->nd_class) { /* Divide */
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case Def:
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df = nd->nd_def;
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switch(df->df_kind) {
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case D_FIELD:
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CodeFieldDesig(df, ds);
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break;
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case D_VARIABLE:
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CodeVarDesig(df, ds);
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break;
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default:
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crash("(CodeDesig) Def");
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}
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break;
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case LinkDef:
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assert(nd->nd_symb == '.');
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CodeDesig(nd->nd_left, ds);
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CodeFieldDesig(nd->nd_def, ds);
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break;
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case Arrsel:
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assert(nd->nd_symb == '[');
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CodeDesig(nd->nd_left, ds);
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CodeAddress(ds);
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CodePExpr(nd->nd_right);
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if (nd->nd_right->nd_type->tp_size > word_size) {
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CodeCoercion(nd->nd_right->nd_type, int_type);
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}
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/* Now load address of descriptor
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*/
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if (IsConformantArray(nd->nd_left->nd_type)) {
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assert(nd->nd_left->nd_class == Def);
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df = nd->nd_left->nd_def;
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if (proclevel > df->df_scope->sc_level) {
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C_lxa((arith) (proclevel - df->df_scope->sc_level));
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C_adp(df->var_off + pointer_size);
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}
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else C_lal(df->var_off + pointer_size);
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}
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else {
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C_lae_dlb(nd->nd_left->nd_type->arr_descr, (arith) 0);
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}
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ds->dsg_kind = DSG_INDEXED;
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break;
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case Arrow:
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assert(nd->nd_symb == '^');
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CodeDesig(nd->nd_right, ds);
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switch(ds->dsg_kind) {
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case DSG_LOADED:
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ds->dsg_kind = DSG_PLOADED;
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break;
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case DSG_INDEXED:
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case DSG_PLOADED:
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case DSG_PFIXED:
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CodeValue(ds, pointer_size, pointer_align);
|
|
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");
|
|
}
|
|
}
|