git.sur5r.net Git - cc65/blob - src/cc65/coptc02.c

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                 coptc02.h                                 */
   4 /*                                                                           */
   5 /*                       65C02 specific optimizations                        */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2001      Ullrich von Bassewitz                                       */
  10 /*               Wacholderweg 14                                             */
  11 /*               D-70597 Stuttgart                                           */
  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 #include <string.h>
  37
  38 /* cc65 */
  39 #include "codeent.h"
  40 #include "codeinfo.h"
  41 #include "error.h"
  42 #include "coptc02.h"
  43
  44
  45
  46 /*****************************************************************************/
  47 /*                                   Data                                    */
  48 /*****************************************************************************/
  49
  50
  51
  52 /*****************************************************************************/
  53 /*                             Helper functions                              */
  54 /*****************************************************************************/
  55
  56
  57
  58 /*****************************************************************************/
  59 /*                                   Code                                    */
  60 /*****************************************************************************/
  61
  62
  63
  64 unsigned Opt65C02Ind (CodeSeg* S)
  65 /* Try to use the indirect addressing mode where possible */
  66 {
  67     unsigned Changes = 0;
  68     unsigned I;
  69
  70     /* Generate register info for this step */
  71     CS_GenRegInfo (S);
  72
  73     /* Walk over the entries */
  74     I = 0;
  75     while (I < CS_GetEntryCount (S)) {
  76
  77         /* Get next entry */
  78         CodeEntry* E = CS_GetEntry (S, I);
  79
  80         /* Check for addressing mode indirect indexed Y where Y is zero.
  81          * Note: All opcodes that are available as (zp),y are also available
  82          * as (zp), so we can ignore the actual opcode here.
  83          */
  84         if (E->AM == AM65_ZP_INDY && E->RI->In.RegY == 0) {
  85
  86             /* Replace it by indirect addressing mode */
  87             CodeEntry* X = NewCodeEntry (E->OPC, AM65_ZP_IND, E->Arg, 0, E->LI);
  88             CS_InsertEntry (S, X, I+1);
  89             CS_DelEntry (S, I);
  90
  91             /* We had changes */
  92             ++Changes;
  93
  94         }
  95
  96         /* Next entry */
  97         ++I;
  98
  99     }
 100
 101     /* Free register info */
 102     CS_FreeRegInfo (S);
 103
 104     /* Return the number of changes made */
 105     return Changes;
 106 }
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