compilers/linux86-0.16.17/bcc/preserve.c

   1 /* preserve.c - preserve opererands or registers in use for bcc */
   2
   3 /* Copyright (C) 1992 Bruce Evans */
   4
   5 #include "bcc.h"
   6 #include "gencode.h"
   7 #include "reg.h"
   8 #include "type.h"
   9 #include "scan.h"
  10
  11 /* change stack ptr without changing condition codes */
  12
  13 PUBLIC void changesp(newsp, absflag)
  14 offset_T newsp;
  15 bool_pt absflag;
  16 {
  17     if (newsp != sp || ((bool_t) absflag && switchnow != NULL))
  18     {
  19 #ifdef FRAMEPOINTER
  20         if (newsp != framep || (!(bool_t) absflag && switchnow != NULL))
  21         {
  22             int off;
  23             outleasp();
  24             if (!(bool_t) absflag && switchnow != NULL)
  25                 outswoffset(off = newsp);
  26             else
  27                 outoffset(off = newsp - framep);
  28 #ifndef NO_DEL_PUSH
  29             if (optimise && !callersaves && off < 0)
  30             {
  31                 outstr("+");
  32                 outstr(funcname);
  33                 outstr(".off");
  34             }
  35 #endif
  36             outindframereg();
  37             outnl();
  38         }
  39         else
  40             regtransfer(FRAMEREG, STACKREG);
  41         sp = newsp;
  42         if (framep == 0)
  43             bugerror("no frame pointer");
  44 #else
  45 # ifdef I8088
  46         outleasp();
  47         outoffset(newsp - sp);
  48         outindstackreg();
  49         outnl();
  50 # else
  51         modstk(newsp);          /* this should preserve CC */
  52 # endif
  53 #endif /* FRAMEPOINTER */
  54     }
  55 }
  56
  57 /* load source to any while preserving target */
  58
  59 PUBLIC void loadpres(source, target)
  60 struct symstruct *source;
  61 struct symstruct *target;
  62 {
  63     store_t regmark;
  64
  65     if (target->storage & ALLDATREGS)
  66     {
  67         if (source->type->scalar & CHAR)
  68         {
  69             push(target);
  70             load(source, DREG);
  71         }
  72         else
  73             load(source, getindexreg());
  74     }
  75     else
  76     {
  77         regmark = reguse;
  78         reguse |= target->storage;
  79         loadany(source);
  80         reguse = regmark;
  81     }
  82 }
  83
  84 /* change stack ptr */
  85
  86 PUBLIC void modstk(newsp)
  87 offset_T newsp;
  88 {
  89     if (newsp != sp)
  90     {
  91 #ifdef FRAMEPOINTER
  92         if (newsp != framep || framep == 0 || switchnow != NULL)
  93             addconst(newsp - sp, STACKREG);
  94         else
  95             regtransfer(FRAMEREG, STACKREG);
  96 #else
  97 # ifdef I8088
  98         addconst(newsp - sp, STACKREG);
  99 # else
 100         outleasp();
 101         outoffset(newsp - sp);
 102         outncspregname();
 103 # endif
 104 #endif
 105         sp = newsp;
 106     }
 107 }
 108
 109 /* preserve target without changing source */
 110
 111 PUBLIC void pres2(source, target)
 112 struct symstruct *source;
 113 struct symstruct *target;
 114 {
 115     if (target->storage & allregs)
 116     {
 117         if (target->storage & (allregs - allindregs) /* XXX */ ||
 118             (target->indcount == 0 &&
 119              target->type->scalar & (DLONG | RSCALAR)))
 120             push(target);       /* XXX - perhaps not float */
 121         else if (((target->storage | reguse) & allindregs) == allindregs)
 122         {
 123             loadpres(target, source);
 124             push(target);
 125         }
 126         else
 127             reguse |= target->storage;
 128     }
 129 }
 130
 131 /* preserve source */
 132
 133 PUBLIC void preserve(source)
 134 struct symstruct *source;
 135 {
 136     if (source->storage & allregs)
 137     {
 138         if (source->storage & (allregs - allindregs) /* XXX */ ||
 139             ((source->storage | reguse) & allindregs) == allindregs)
 140             push(source);
 141         else
 142             reguse |= source->storage;
 143     }
 144 }
 145
 146 /* preserve lvalue target without changing source or target */
 147
 148 PUBLIC store_pt preslval(source, target)
 149 struct symstruct *source;
 150 struct symstruct *target;
 151 {
 152     store_pt regpushed;
 153
 154     if (target->indcount == 0)
 155         reguse &= ~target->storage;
 156     else
 157         reguse = (target->storage | reguse) & allindregs;
 158     if (!((source->type->scalar | target->type->scalar) & (DLONG | RSCALAR))
 159         || reguse != allindregs)
 160         return 0;               /* XXX - perhaps not float */
 161     reguse = source->storage | target->storage; /* free one other than s/t */
 162     pushreg(regpushed = getindexreg());
 163     reguse = ~(store_t) regpushed & allindregs;
 164     return regpushed;
 165 }
 166
 167 PUBLIC void recovlist(reglist)
 168 store_pt reglist;
 169 {
 170     poplist(reglist);
 171     reguse |= (store_t) reglist;
 172 }
 173
 174 #ifdef I8088
 175 PRIVATE smalin_t regoffset[] = {0, 0, 0, 1, 2, 3, 0, 0, 0, 4, 5};
 176  /* CONSTANT, BREG, ax = DREG, bx = INDREG0, si = INDREG1, di = INDREG2 */
 177  /* LOCAL, GLOBAL, STACKREG, cx = DATREG1, dx = DATREG2 */
 178 #endif
 179 #ifdef MC6809
 180 PRIVATE smalin_t regoffset[] = {0, 0, 0, 1, 3, 2};
 181  /* CONSTANT, BREG, DREG, XREG = INDREG0, UREG = INDREG1, YREG = INDREG2 */
 182 #endif
 183
 184 PUBLIC void savereturn(savelist, saveoffset)
 185 store_pt savelist;
 186 offset_T saveoffset;
 187 {
 188     store_t reg;
 189     smalin_t *regoffptr;
 190     offset_T spoffset;
 191
 192     if (savelist == 0)
 193         return;
 194 #ifdef MC6809 /* must check this */
 195     if (savelist == XREG || savelist == INDREG1)
 196         saveoffset -= accregsize;       /* patch for DREG/YREG not saved */
 197 #endif
 198     for (reg = 1, regoffptr = regoffset; reg != 0; ++regoffptr, reg <<= 1)
 199         if (reg & savelist)
 200         {
 201             outstore();
 202             spoffset = saveoffset + *regoffptr * maxregsize;
 203 #ifdef I8088
 204 # ifdef FRAMEPOINTER
 205             if (switchnow != NULL)
 206                 outswoffset(spoffset);
 207             else
 208                 outoffset(spoffset - framep);
 209             outindframereg();
 210 # else
 211             outoffset(spoffset - sp);
 212             outindstackreg();
 213 # endif
 214             outncregname(reg);
 215 #endif
 216 #ifdef MC6809
 217             if (reg == YREG)
 218                 bumplc();
 219             outregname(reg);
 220             outtab();
 221             outoffset(spoffset - sp);
 222             outncspregname();
 223 #endif
 224         }
 225 }