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cc65/src/ca65/easw16.c

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/*****************************************************************************/
/* */
/* easw16.c */
/* */
/* SWEET16 effective address parsing for the ca65 macroassembler */
/* */
/* */
/* */
/* (C) 2004 Ullrich von Bassewitz */
/* R<>merstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
/* ca65 */
#include "ea.h"
#include "ea65.h"
#include "error.h"
#include "expr.h"
#include "instr.h"
#include "nexttok.h"
/*****************************************************************************/
/* Code */
/*****************************************************************************/
void GetSweet16EA (EffAddr* A)
/* Parse an effective address, return the result in A */
{
/* Clear the output struct */
A->AddrModeSet = 0;
A->Expr = 0;
A->Reg = 0;
/* Parse the effective address */
if (TokIsSep (Tok)) {
A->AddrModeSet = AMSW16_IMP;
} else if (Tok == TOK_AT) {
/* @reg */
A->AddrModeSet = AMSW16_IND;
NextTok ();
if (Tok != TOK_REG) {
ErrorSkip ("Register expected");
A->Reg = 0;
} else {
A->Reg = (unsigned) IVal;
NextTok ();
}
} else if (Tok == TOK_REG) {
A->Reg = (unsigned) IVal;
NextTok ();
if (Tok == TOK_COMMA) {
/* Rx, Constant */
NextTok ();
A->Expr = Expression ();
A->AddrModeSet = AMSW16_IMM;
} else {
A->AddrModeSet = AMSW16_REG;
}
} else {
/* OPC ea */
A->Expr = Expression ();
A->AddrModeSet = AMSW16_BRA;
}
}