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

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                coptpush.c                                 */
   4 /*                                                                           */
   5 /*                          Optimize push sequences                          */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2001-2012, Ullrich von Bassewitz                                      */
  10 /*                Roemerstrasse 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 /* cc65 */
  37 #include "codeent.h"
  38 #include "codeinfo.h"
  39 #include "coptpush.h"
  40
  41
  42
  43 /*****************************************************************************/
  44 /*                                   Code                                    */
  45 /*****************************************************************************/
  46
  47
  48
  49 unsigned OptPush1 (CodeSeg* S)
  50 /* Given a sequence
  51 **
  52 **     jsr     ldaxysp
  53 **     jsr     pushax
  54 **
  55 ** If a/x are not used later, and Y is known, replace that by
  56 **
  57 **     ldy     #xx+2
  58 **     jsr     pushwysp
  59 **
  60 ** saving 3 bytes and several cycles.
  61 */
  62 {
  63     unsigned I;
  64     unsigned Changes = 0;
  65
  66     /* Walk over the entries */
  67     I = 0;
  68     while (I < CS_GetEntryCount (S)) {
  69
  70         CodeEntry* L[2];
  71
  72         /* Get next entry */
  73         L[0] = CS_GetEntry (S, I);
  74
  75         /* Check for the sequence */
  76         if (CE_IsCallTo (L[0], "ldaxysp")               &&
  77             RegValIsKnown (L[0]->RI->In.RegY)           &&
  78             L[0]->RI->In.RegY < 0xFE                    &&
  79             (L[1] = CS_GetNextEntry (S, I)) != 0        &&
  80             !CE_HasLabel (L[1])                         &&
  81             CE_IsCallTo (L[1], "pushax")                &&
  82             !RegAXUsed (S, I+2)) {
  83
  84             /* Insert new code behind the pushax */
  85             const char* Arg;
  86             CodeEntry* X;
  87
  88             /* ldy     #xx+1 */
  89             Arg = MakeHexArg (L[0]->RI->In.RegY+2);
  90             X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[0]->LI);
  91             CS_InsertEntry (S, X, I+2);
  92
  93             /* jsr pushwysp */
  94             X = NewCodeEntry (OP65_JSR, AM65_ABS, "pushwysp", 0, L[1]->LI);
  95             CS_InsertEntry (S, X, I+3);
  96
  97             /* Delete the old code */
  98             CS_DelEntries (S, I, 2);
  99
 100             /* Remember, we had changes */
 101             ++Changes;
 102
 103         }
 104
 105         /* Next entry */
 106         ++I;
 107
 108     }
 109
 110     /* Return the number of changes made */
 111     return Changes;
 112 }
 113
 114
 115
 116 unsigned OptPush2 (CodeSeg* S)
 117 /* A sequence
 118 **
 119 **     jsr     ldaxidx
 120 **     jsr     pushax
 121 **
 122 ** may get replaced by
 123 **
 124 **     jsr     pushwidx
 125 */
 126 {
 127     unsigned I;
 128     unsigned Changes = 0;
 129
 130     /* Walk over the entries */
 131     I = 0;
 132     while (I < CS_GetEntryCount (S)) {
 133
 134         CodeEntry* L[2];
 135
 136         /* Get next entry */
 137         L[0] = CS_GetEntry (S, I);
 138
 139         /* Check for the sequence */
 140         if (CE_IsCallTo (L[0], "ldaxidx")               &&
 141             (L[1] = CS_GetNextEntry (S, I)) != 0        &&
 142             !CE_HasLabel (L[1])                         &&
 143             CE_IsCallTo (L[1], "pushax")) {
 144
 145             /* Insert new code behind the pushax */
 146             CodeEntry* X;
 147
 148             /* jsr pushwidx */
 149             X = NewCodeEntry (OP65_JSR, AM65_ABS, "pushwidx", 0, L[1]->LI);
 150             CS_InsertEntry (S, X, I+2);
 151
 152             /* Delete the old code */
 153             CS_DelEntries (S, I, 2);
 154
 155             /* Remember, we had changes */
 156             ++Changes;
 157
 158         }
 159
 160         /* Next entry */
 161         ++I;
 162
 163     }
 164
 165     /* Return the number of changes made */
 166     return Changes;
 167 }