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->Bank = 0;
  59     A->Expr = 0;
  60
  61     /* Handle an addressing size override */
  62     switch (Tok) {
  63         case TOK_OVERRIDE_ZP:
  64             Restrictions = AM_DIR | AM_DIR_X | AM_DIR_Y;
  65             NextTok ();
  66             break;
  67
  68         case TOK_OVERRIDE_ABS:
  69             Restrictions = AM_ABS | AM_ABS_X | AM_ABS_Y;
  70             NextTok ();
  71             break;
  72
  73         case TOK_OVERRIDE_FAR:
  74             Restrictions = AM_ABS_LONG | AM_ABS_LONG_X;
  75             NextTok ();
  76             break;
  77
  78         default:
  79             Restrictions = ~0UL;        /* None */
  80             break;
  81     }
  82
  83     /* Parse the effective address */
  84     if (TokIsSep (Tok)) {
  85
  86         A->AddrModeSet = AM_IMPLICIT;
  87
  88     } else if (Tok == TOK_HASH) {
  89
  90         /* #val */
  91         NextTok ();
  92         A->Expr  = Expression ();
  93         A->AddrModeSet = AM_IMM;
  94
  95     } else if (Tok == TOK_A) {
  96
  97         NextTok ();
  98         A->AddrModeSet = AM_ACCU;
  99
 100     } else if (Tok == TOK_LBRACK) {
 101
 102         /* [dir] or [dir],y */
 103         NextTok ();
 104         A->Expr = Expression ();
 105         Consume (TOK_RBRACK, ERR_RBRACK_EXPECTED);
 106         if (Tok == TOK_COMMA) {
 107             /* [dir],y */
 108             NextTok ();
 109             Consume (TOK_Y, ERR_Y_EXPECTED);
 110             A->AddrModeSet = AM_DIR_IND_LONG_Y;
 111         } else {
 112             /* [dir] */
 113             A->AddrModeSet = AM_DIR_IND_LONG;
 114         }
 115
 116     } else if (Tok == TOK_LPAREN) {
 117
 118         /* One of the indirect modes */
 119         NextTok ();
 120         A->Expr = Expression ();
 121
 122         if (Tok == TOK_COMMA) {
 123
 124             /* (expr,X) or (rel,S),y */
 125             NextTok ();
 126             if (Tok == TOK_X) {
 127                 /* (adr,x) */
 128                 NextTok ();
 129                 A->AddrModeSet = AM_ABS_X_IND | AM_DIR_X_IND;
 130                 ConsumeRParen ();
 131             } else if (Tok == TOK_S) {
 132                 /* (rel,s),y */
 133                 NextTok ();
 134                 A->AddrModeSet = AM_STACK_REL_IND_Y;
 135                 ConsumeRParen ();
 136                 ConsumeComma ();
 137                 Consume (TOK_Y, ERR_Y_EXPECTED);
 138             } else {
 139                 Error (ERR_SYNTAX);
 140             }
 141
 142         } else {
 143
 144             /* (adr) or (adr),y */
 145             ConsumeRParen ();
 146             if (Tok == TOK_COMMA) {
 147                 /* (adr),y */
 148                 NextTok ();
 149                 Consume (TOK_Y, ERR_Y_EXPECTED);
 150                 A->AddrModeSet = AM_DIR_IND_Y;
 151             } else {
 152                 /* (adr) */
 153                 A->AddrModeSet = AM_ABS_IND | AM_DIR_IND;
 154             }
 155         }
 156
 157     } else {
 158
 159         /* Remaining stuff:
 160          *
 161          * adr
 162          * bank.adr
 163          * adr,x
 164          * bank.adr,x
 165          * adr,y
 166          * adr,s
 167          */
 168         A->Expr = Expression ();
 169
 170         if (Tok == TOK_DOT) {
 171
 172             /* Expr was a bank specification: bank.adr or bank.adr,x */
 173             A->Bank = A->Expr;
 174             NextTok ();
 175             A->Expr = Expression ();
 176             if (Tok == TOK_COMMA) {
 177                 /* bank.adr,x */
 178                 NextTok ();
 179                 Consume (TOK_X, ERR_X_EXPECTED);
 180                 A->AddrModeSet = AM_ABS_LONG_X;
 181             } else {
 182                 /* bank.adr */
 183                 A->AddrModeSet = AM_ABS_LONG;
 184             }
 185
 186         } else {
 187
 188             if (Tok == TOK_COMMA) {
 189
 190                 NextTok ();
 191                 switch (Tok) {
 192
 193                     case TOK_X:
 194                         A->AddrModeSet = AM_ABS_LONG_X | AM_ABS_X | AM_DIR_X;
 195                         NextTok ();
 196                         break;
 197
 198                     case TOK_Y:
 199                         A->AddrModeSet = AM_ABS_Y | AM_DIR_Y;
 200                         NextTok ();
 201                         break;
 202
 203                     case TOK_S:
 204                         A->AddrModeSet = AM_STACK_REL;
 205                         NextTok ();
 206                         break;
 207
 208                     default:
 209                         Error (ERR_SYNTAX);
 210
 211                 }
 212
 213             } else {
 214
 215                 A->AddrModeSet = AM_ABS_LONG | AM_ABS | AM_DIR;
 216
 217             }
 218         }
 219     }
 220
 221     /* Apply addressing mode overrides */
 222     A->AddrModeSet &= Restrictions;
 223 }
 224
 225
 226