/*****************************************************************************/
/*                                                                           */
/*                                 coptneg.h                                 */
/*                                                                           */
/*                        Optimize negation sequences                        */
/*                                                                           */
/*                                                                           */
/*                                                                           */
/* (C) 2001-2012, Ullrich von Bassewitz                                      */
/*                Roemerstrasse 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 COPTNEG_H
#define COPTNEG_H



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



/*****************************************************************************/
/*                            bnega optimizations                            */
/*****************************************************************************/



unsigned OptBNegA1 (CodeSeg* S);
/* Check for
 *
 *      ldx     #$00
 *      lda     ..
 *      jsr     bnega
 *
 * Remove the ldx if the lda does not use it.
 */

unsigned OptBNegA2 (CodeSeg* S);
/* Check for
 *
 *      lda     ..
 *      jsr     bnega
 *      jeq/jne ..
 *
 * Adjust the conditional branch and remove the call to the subroutine.
 */



/*****************************************************************************/
/*                            bnegax optimizations                           */
/*****************************************************************************/



unsigned OptBNegAX1 (CodeSeg* S);
/* On a call to bnegax, if X is zero, the result depends only on the value in
 * A, so change the call to a call to bnega. This will get further optimized
 * later if possible.
 */

unsigned OptBNegAX2 (CodeSeg* S);
/* Search for the sequence:
 *
 *      lda     (xx),y
 *      tax
 *      dey
 *      lda     (xx),y
 *      jsr     bnegax
 *      jne/jeq ...
 *
 * and replace it by
 *
 *      lda     (xx),y
 *      dey
 *      ora     (xx),y
 *      jeq/jne ...
 */

unsigned OptBNegAX3 (CodeSeg* S);
/* Search for the sequence:
 *
 *      lda     xx
 *      ldx     yy
 *      jsr     bnegax
 *      jne/jeq ...
 *
 * and replace it by
 *
 *      lda     xx
 *      ora     xx+1
 *      jeq/jne ...
 */

unsigned OptBNegAX4 (CodeSeg* S);
/* Search for the sequence:
 *
 *      jsr     xxx
 *      jsr     bnega(x)
 *      jeq/jne ...
 *
 * and replace it by:
 *
 *      jsr     xxx
 *      <boolean test>
 *      jne/jeq ...
 */



/*****************************************************************************/
/*                            negax optimizations                            */
/*****************************************************************************/



unsigned OptNegAX1 (CodeSeg* S);
/* Search for a call to negax and replace it by
 *
 *      eor     #$FF
 *      clc
 *      adc     #$01
 *
 * if X isn't used later.
 */

unsigned OptNegAX2 (CodeSeg* S);
/* Search for a call to negax and replace it by
 *
 *      ldx     #$FF
 *      eor     #$FF
 *      clc
 *      adc     #$01
 *      bne     L1
 *      inx
 * L1:
 *
 * if X is known and zero on entry.
 */



/*****************************************************************************/
/*                           complax optimizations                           */
/*****************************************************************************/



unsigned OptComplAX1 (CodeSeg* S);
/* Search for a call to complax and replace it by
 *
 *      eor     #$FF
 *
 * if X isn't used later.
 */



/* End of coptneg.h */

#endif



