git.sur5r.net Git - cc65/blob - src/cc65/coptstore.h

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                  coptstore.h                              */
   4 /*                                                                           */
   5 /*                                Optimize stores                            */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2002-2006, 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 #ifndef COPTSTORE_H
  37 #define COPTSTORE_H
  38
  39
  40
  41 /* cc65 */
  42 #include "codeseg.h"
  43
  44
  45
  46 /*****************************************************************************/
  47 /*                                   Code                                    */
  48 /*****************************************************************************/
  49
  50
  51
  52 unsigned OptStore1 (CodeSeg* S);
  53 /* Search for the sequence
  54  *
  55  *      ldy     #n
  56  *      jsr     staxysp
  57  *      ldy     #n+1
  58  *      jsr     ldaxysp
  59  *
  60  * and remove the useless load, provided that the next insn doesn't use flags
  61  * from the load.
  62  */
  63
  64 unsigned OptStore2 (CodeSeg* S);
  65 /* Search for a call to staxysp. If the ax register is not used later, and
  66  * the value is constant, just use the A register and store directly into the
  67  * stack.
  68  */
  69
  70 unsigned OptStore3 (CodeSeg* S);
  71 /* Search for a call to steaxysp. If the eax register is not used later, and
  72  * the value is constant, just use the A register and store directly into the
  73  * stack.
  74  */
  75
  76 unsigned OptStore4 (CodeSeg* S);
  77 /* Search for the sequence
  78  *
  79  *      sta     xx
  80  *      stx     yy
  81  *      lda     xx
  82  *      ldx     yy
  83  *
  84  * and remove the useless load, provided that the next insn doesn't use flags
  85  * from the load.
  86  */
  87
  88 unsigned OptStore5 (CodeSeg* S);
  89 /* Search for the sequence
  90  *
  91  *      lda     foo
  92  *      ldx     bar
  93  *      sta     something
  94  *      stx     something-else
  95  *
  96  * and replace it by
  97  *
  98  *      lda     foo
  99  *      sta     something
 100  *      lda     bar
 101  *      sta     something-else
 102  *
 103  * if X is not used later. This replacement doesn't save any cycles or bytes,
 104  * but it keeps the value of X, which may be reused later.
 105  */
 106
 107
 108
 109 /* End of coptstore.h */
 110
 111 #endif
 112
 113
 114