git.sur5r.net Git - cc65/blob - src/ca65/ea65.c

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                  ea65.c                                   */
   4 /*                                                                           */
   5 /*        65XX effective address parsing for the ca65 macroassembler         */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 1998-2011, Ullrich von Bassewitz                                      */
  10 /*                Roemerstrasse 52                                           */
  11 /*                D-70794 Filderstadt                                        */
  12 /* EMail:         uz@cc65.org                                                */
  13 /*                                                                           */
  14 /*                                                                           */
  15 /* This software is provided 'as-is', without any expressed or implied       */
  16 /* warranty.  In no event will the authors be held liable for any damages    */
  17 /* arising from the use of this software.                                    */
  18 /*                                                                           */
  19 /* Permission is granted to anyone to use this software for any purpose,     */
  20 /* including commercial applications, and to alter it and redistribute it    */
  21 /* freely, subject to the following restrictions:                            */
  22 /*                                                                           */
  23 /* 1. The origin of this software must not be misrepresented; you must not   */
  24 /*    claim that you wrote the original software. If you use this software   */
  25 /*    in a product, an acknowledgment in the product documentation would be  */
  26 /*    appreciated but is not required.                                       */
  27 /* 2. Altered source versions must be plainly marked as such, and must not   */
  28 /*    be misrepresented as being the original software.                      */
  29 /* 3. This notice may not be removed or altered from any source              */
  30 /*    distribution.                                                          */
  31 /*                                                                           */
  32 /*****************************************************************************/
  33
  34
  35
  36 /* ca65 */
  37 #include "ea.h"
  38 #include "ea65.h"
  39 #include "error.h"
  40 #include "expr.h"
  41 #include "instr.h"
  42 #include "nexttok.h"
  43 #include "global.h"
  44
  45
  46
  47 /*****************************************************************************/
  48 /*                                   Code                                    */
  49 /*****************************************************************************/
  50
  51
  52
  53 void GetEA (EffAddr* A)
  54 /* Parse an effective address, return the result in A */
  55 {
  56     unsigned long Restrictions;
  57     token_t IndirectEnter;
  58     token_t IndirectLeave;
  59     const char* IndirectExpect;
  60
  61     /* Choose syntax for indirection */
  62     if (BracketAsIndirect) {
  63         IndirectEnter = TOK_LBRACK;
  64         IndirectLeave = TOK_RBRACK;
  65         IndirectExpect = "']' expected";
  66     } else {
  67         IndirectEnter = TOK_LPAREN;
  68         IndirectLeave = TOK_RPAREN;
  69         IndirectExpect = "')' expected";
  70     }
  71
  72     /* Clear the output struct */
  73     A->AddrModeSet = 0;
  74     A->Expr = 0;
  75
  76     /* Handle an addressing size override */
  77     switch (CurTok.Tok) {
  78         case TOK_OVERRIDE_ZP:
  79             Restrictions = AM65_DIR | AM65_DIR_X | AM65_DIR_Y;
  80             NextTok ();
  81             break;
  82
  83         case TOK_OVERRIDE_ABS:
  84             Restrictions = AM65_ABS | AM65_ABS_X | AM65_ABS_Y;
  85             NextTok ();
  86             break;
  87
  88         case TOK_OVERRIDE_FAR:
  89             Restrictions = AM65_ABS_LONG | AM65_ABS_LONG_X;
  90             NextTok ();
  91             break;
  92
  93         default:
  94             Restrictions = ~0UL;        /* None */
  95             break;
  96     }
  97
  98     /* Parse the effective address */
  99     if (TokIsSep (CurTok.Tok)) {
 100
 101         A->AddrModeSet = AM65_IMPLICIT;
 102
 103     } else if (CurTok.Tok == TOK_HASH) {
 104
 105         /* #val */
 106         NextTok ();
 107         A->Expr  = Expression ();
 108         A->AddrModeSet = AM65_ALL_IMM;
 109
 110     } else if (CurTok.Tok == TOK_A) {
 111
 112         NextTok ();
 113         A->AddrModeSet = AM65_ACCU;
 114
 115     } else if (CurTok.Tok == IndirectEnter) {
 116
 117         /* One of the indirect modes */
 118         NextTok ();
 119         A->Expr = Expression ();
 120
 121         if (CurTok.Tok == TOK_COMMA) {
 122
 123             /* (expr,X) or (rel,S),y */
 124             NextTok ();
 125             if (CurTok.Tok == TOK_X) {
 126                 /* (adr,x) */
 127                 NextTok ();
 128                 A->AddrModeSet = AM65_ABS_X_IND | AM65_DIR_X_IND;
 129                 Consume (IndirectLeave, IndirectExpect);
 130             } else if (CurTok.Tok == TOK_S) {
 131                 /* (rel,s),y */
 132                 NextTok ();
 133                 A->AddrModeSet = AM65_STACK_REL_IND_Y;
 134                 Consume (IndirectLeave, IndirectExpect);
 135                 ConsumeComma ();
 136                 Consume (TOK_Y, "`Y' expected");
 137             } else {
 138                 Error ("Syntax error");
 139             }
 140
 141         } else {
 142
 143             /* (adr) or (adr),y */
 144             Consume (IndirectLeave, IndirectExpect);
 145             if (CurTok.Tok == TOK_COMMA) {
 146                 /* (adr),y */
 147                 NextTok ();
 148                 Consume (TOK_Y, "`Y' expected");
 149                 A->AddrModeSet = AM65_DIR_IND_Y;
 150             } else {
 151                 /* (adr) */
 152                 A->AddrModeSet = AM65_ABS_IND | AM65_ABS_IND_LONG | AM65_DIR_IND;
 153             }
 154         }
 155
 156     } else if (CurTok.Tok == TOK_LBRACK) {
 157
 158         /* Never executed if BracketAsIndirect feature is enabled. */
 159         /* [dir] or [dir],y */
 160         NextTok ();
 161         A->Expr = Expression ();
 162         Consume (TOK_RBRACK, "']' expected");
 163         if (CurTok.Tok == TOK_COMMA) {
 164             /* [dir],y */
 165             NextTok ();
 166             Consume (TOK_Y, "`Y' expected");
 167             A->AddrModeSet = AM65_DIR_IND_LONG_Y;
 168         } else {
 169             /* [dir] */
 170             A->AddrModeSet = AM65_DIR_IND_LONG | AM65_ABS_IND_LONG;
 171         }
 172
 173     } else {
 174
 175         /* Remaining stuff:
 176         **
 177         ** adr
 178         ** adr,x
 179         ** adr,y
 180         ** adr,s
 181         */
 182         A->Expr = Expression ();
 183
 184         if (CurTok.Tok == TOK_COMMA) {
 185
 186             NextTok ();
 187             switch (CurTok.Tok) {
 188
 189                 case TOK_X:
 190                     A->AddrModeSet = AM65_ABS_LONG_X | AM65_ABS_X | AM65_DIR_X;
 191                     NextTok ();
 192                     break;
 193
 194                 case TOK_Y:
 195                     A->AddrModeSet = AM65_ABS_Y | AM65_DIR_Y;
 196                     NextTok ();
 197                     break;
 198
 199                 case TOK_S:
 200                     A->AddrModeSet = AM65_STACK_REL;
 201                     NextTok ();
 202                     break;
 203
 204                 default:
 205                     Error ("Syntax error");
 206
 207             }
 208
 209         } else {
 210
 211             A->AddrModeSet = AM65_ABS_LONG | AM65_ABS | AM65_DIR;
 212
 213         }
 214     }
 215
 216     /* Apply addressing mode overrides */
 217     A->AddrModeSet &= Restrictions;
 218 }