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

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                   ea.c                                    */
   4 /*                                                                           */
   5 /*           Effective address parsing for the ca65 macroassembler           */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 1998-2003 Ullrich von Bassewitz                                       */
  10 /*               Römerstraße 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 /* ld65 */
  37 #include "error.h"
  38 #include "expr.h"
  39 #include "instr.h"
  40 #include "nexttok.h"
  41 #include "ea.h"
  42
  43
  44
  45 /*****************************************************************************/
  46 /*                                   Code                                    */
  47 /*****************************************************************************/
  48
  49
  50
  51 void GetEA (EffAddr* A)
  52 /* Parse an effective address, return the result in A */
  53 {
  54     unsigned long Restrictions;
  55
  56     /* Clear the output struct */
  57     A->AddrModeSet = 0;
  58     A->Expr = 0;
  59
  60     /* Handle an addressing size override */
  61     switch (Tok) {
  62         case TOK_OVERRIDE_ZP:
  63             Restrictions = AM_DIR | AM_DIR_X | AM_DIR_Y;
  64             NextTok ();
  65             break;
  66
  67         case TOK_OVERRIDE_ABS:
  68             Restrictions = AM_ABS | AM_ABS_X | AM_ABS_Y;
  69             NextTok ();
  70             break;
  71
  72         case TOK_OVERRIDE_FAR:
  73             Restrictions = AM_ABS_LONG | AM_ABS_LONG_X;
  74             NextTok ();
  75             break;
  76
  77         default:
  78             Restrictions = ~0UL;        /* None */
  79             break;
  80     }
  81
  82     /* Parse the effective address */
  83     if (TokIsSep (Tok)) {
  84
  85         A->AddrModeSet = AM_IMPLICIT;
  86
  87     } else if (Tok == TOK_HASH) {
  88
  89         /* #val */
  90         NextTok ();
  91         A->Expr  = Expression ();
  92         A->AddrModeSet = AM_IMM;
  93
  94     } else if (Tok == TOK_A) {
  95
  96         NextTok ();
  97         A->AddrModeSet = AM_ACCU;
  98
  99     } else if (Tok == TOK_LBRACK) {
 100
 101         /* [dir] or [dir],y */
 102         NextTok ();
 103         A->Expr = Expression ();
 104         Consume (TOK_RBRACK, "']' expected");
 105         if (Tok == TOK_COMMA) {
 106             /* [dir],y */
 107             NextTok ();
 108             Consume (TOK_Y, "`Y' expected");
 109             A->AddrModeSet = AM_DIR_IND_LONG_Y;
 110         } else {
 111             /* [dir] */
 112             A->AddrModeSet = AM_DIR_IND_LONG;
 113         }
 114
 115     } else if (Tok == TOK_LPAREN) {
 116
 117         /* One of the indirect modes */
 118         NextTok ();
 119         A->Expr = Expression ();
 120
 121         if (Tok == TOK_COMMA) {
 122
 123             /* (expr,X) or (rel,S),y */
 124             NextTok ();
 125             if (Tok == TOK_X) {
 126                 /* (adr,x) */
 127                 NextTok ();
 128                 A->AddrModeSet = AM_ABS_X_IND | AM_DIR_X_IND;
 129                 ConsumeRParen ();
 130             } else if (Tok == TOK_S) {
 131                 /* (rel,s),y */
 132                 NextTok ();
 133                 A->AddrModeSet = AM_STACK_REL_IND_Y;
 134                 ConsumeRParen ();
 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             ConsumeRParen ();
 145             if (Tok == TOK_COMMA) {
 146                 /* (adr),y */
 147                 NextTok ();
 148                 Consume (TOK_Y, "`Y' expected");
 149                 A->AddrModeSet = AM_DIR_IND_Y;
 150             } else {
 151                 /* (adr) */
 152                 A->AddrModeSet = AM_ABS_IND | AM_DIR_IND;
 153             }
 154         }
 155
 156     } else {
 157
 158         /* Remaining stuff:
 159          *
 160          * adr
 161          * adr,x
 162          * adr,y
 163          * adr,s
 164          */
 165         A->Expr = Expression ();
 166
 167         if (Tok == TOK_COMMA) {
 168
 169             NextTok ();
 170             switch (Tok) {
 171
 172                 case TOK_X:
 173                     A->AddrModeSet = AM_ABS_LONG_X | AM_ABS_X | AM_DIR_X;
 174                     NextTok ();
 175                     break;
 176
 177                 case TOK_Y:
 178                     A->AddrModeSet = AM_ABS_Y | AM_DIR_Y;
 179                     NextTok ();
 180                     break;
 181
 182                 case TOK_S:
 183                     A->AddrModeSet = AM_STACK_REL;
 184                     NextTok ();
 185                     break;
 186
 187                 default:
 188                     Error ("Syntax error");
 189
 190             }
 191
 192         } else {
 193
 194             A->AddrModeSet = AM_ABS_LONG | AM_ABS | AM_DIR;
 195
 196         }
 197     }
 198
 199     /* Apply addressing mode overrides */
 200     A->AddrModeSet &= Restrictions;
 201 }
 202
 203
 204