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206 lines
6.0 KiB
C
206 lines
6.0 KiB
C
/*****************************************************************************/
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/* */
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/* ea65.c */
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/* */
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/* 65XX effective address parsing for the ca65 macroassembler */
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/* */
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/* */
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/* */
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/* (C) 1998-2004 Ullrich von Bassewitz */
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/* Römerstrasse 52 */
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/* D-70794 Filderstadt */
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/* EMail: uz@cc65.org */
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/* */
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/* */
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/* This software is provided 'as-is', without any expressed or implied */
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/* warranty. In no event will the authors be held liable for any damages */
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/* arising from the use of this software. */
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/* */
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/* Permission is granted to anyone to use this software for any purpose, */
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/* including commercial applications, and to alter it and redistribute it */
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/* freely, subject to the following restrictions: */
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/* */
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/* 1. The origin of this software must not be misrepresented; you must not */
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/* claim that you wrote the original software. If you use this software */
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/* in a product, an acknowledgment in the product documentation would be */
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/* appreciated but is not required. */
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/* 2. Altered source versions must be plainly marked as such, and must not */
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/* be misrepresented as being the original software. */
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/* 3. This notice may not be removed or altered from any source */
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/* distribution. */
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/* */
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/*****************************************************************************/
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/* ca65 */
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#include "ea.h"
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#include "ea65.h"
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#include "error.h"
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#include "expr.h"
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#include "instr.h"
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#include "nexttok.h"
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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void GetEA (EffAddr* A)
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/* Parse an effective address, return the result in A */
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{
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unsigned long Restrictions;
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/* Clear the output struct */
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A->AddrModeSet = 0;
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A->Expr = 0;
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/* Handle an addressing size override */
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switch (Tok) {
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case TOK_OVERRIDE_ZP:
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Restrictions = AM65_DIR | AM65_DIR_X | AM65_DIR_Y;
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NextTok ();
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break;
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case TOK_OVERRIDE_ABS:
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Restrictions = AM65_ABS | AM65_ABS_X | AM65_ABS_Y;
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NextTok ();
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break;
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case TOK_OVERRIDE_FAR:
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Restrictions = AM65_ABS_LONG | AM65_ABS_LONG_X;
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NextTok ();
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break;
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default:
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Restrictions = ~0UL; /* None */
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break;
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}
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/* Parse the effective address */
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if (TokIsSep (Tok)) {
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A->AddrModeSet = AM65_IMPLICIT;
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} else if (Tok == TOK_HASH) {
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/* #val */
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NextTok ();
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A->Expr = Expression ();
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A->AddrModeSet = AM65_IMM;
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} else if (Tok == TOK_A) {
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NextTok ();
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A->AddrModeSet = AM65_ACCU;
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} else if (Tok == TOK_LBRACK) {
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/* [dir] or [dir],y */
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NextTok ();
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A->Expr = Expression ();
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Consume (TOK_RBRACK, "']' expected");
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if (Tok == TOK_COMMA) {
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/* [dir],y */
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NextTok ();
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Consume (TOK_Y, "`Y' expected");
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A->AddrModeSet = AM65_DIR_IND_LONG_Y;
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} else {
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/* [dir] */
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A->AddrModeSet = AM65_DIR_IND_LONG;
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}
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} else if (Tok == TOK_LPAREN) {
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/* One of the indirect modes */
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NextTok ();
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A->Expr = Expression ();
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if (Tok == TOK_COMMA) {
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/* (expr,X) or (rel,S),y */
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NextTok ();
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if (Tok == TOK_X) {
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/* (adr,x) */
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NextTok ();
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A->AddrModeSet = AM65_ABS_X_IND | AM65_DIR_X_IND;
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ConsumeRParen ();
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} else if (Tok == TOK_S) {
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/* (rel,s),y */
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NextTok ();
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A->AddrModeSet = AM65_STACK_REL_IND_Y;
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ConsumeRParen ();
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ConsumeComma ();
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Consume (TOK_Y, "`Y' expected");
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} else {
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Error ("Syntax error");
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}
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} else {
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/* (adr) or (adr),y */
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ConsumeRParen ();
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if (Tok == TOK_COMMA) {
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/* (adr),y */
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NextTok ();
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Consume (TOK_Y, "`Y' expected");
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A->AddrModeSet = AM65_DIR_IND_Y;
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} else {
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/* (adr) */
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A->AddrModeSet = AM65_ABS_IND | AM65_DIR_IND;
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}
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}
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} else {
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/* Remaining stuff:
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*
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* adr
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* adr,x
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* adr,y
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* adr,s
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*/
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A->Expr = Expression ();
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if (Tok == TOK_COMMA) {
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NextTok ();
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switch (Tok) {
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case TOK_X:
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A->AddrModeSet = AM65_ABS_LONG_X | AM65_ABS_X | AM65_DIR_X;
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NextTok ();
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break;
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case TOK_Y:
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A->AddrModeSet = AM65_ABS_Y | AM65_DIR_Y;
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NextTok ();
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break;
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case TOK_S:
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A->AddrModeSet = AM65_STACK_REL;
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NextTok ();
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break;
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default:
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Error ("Syntax error");
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}
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} else {
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A->AddrModeSet = AM65_ABS_LONG | AM65_ABS | AM65_DIR;
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}
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}
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/* Apply addressing mode overrides */
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A->AddrModeSet &= Restrictions;
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}
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