/*****************************************************************************/
/*                                                                           */
/*                                 coptsub.h                                 */
/*                                                                           */
/*                      Optimize subtraction sequences                       */
/*                                                                           */
/*                                                                           */
/*                                                                           */
/* (C) 2001-2006, Ullrich von Bassewitz                                      */
/*                Römerstrasse 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.                                                          */
/*                                                                           */
/*****************************************************************************/



#ifndef COPTSUB_H
#define COPTSUB_H



/* cc65 */
#include "codeseg.h"



/*****************************************************************************/
/*                           Optimize subtractions                           */
/*****************************************************************************/



unsigned OptSub1 (CodeSeg* S);
/* Search for the sequence
 *
 *      sbc     ...
 *      bcs     L
 *      dex
 * L:
 *
 * and remove the handling of the high byte if X is not used later.
 */

unsigned OptSub2 (CodeSeg* S);
/* Search for the sequence
 *
 *      lda     xx
 *      sec
 *      sta     tmp1
 *      lda     yy
 *      sbc     tmp1
 *      sta     yy
 *
 * and replace it by
 *
 *      sec
 *      lda     yy
 *      sbc     xx
 *      sta     yy
 */

unsigned OptSub3 (CodeSeg* S);
/* Search for a call to decaxn and replace it by an 8 bit sub if the X register
 * is not used later.
 */



/* End of coptsub.h */

#endif



