1/*****************************************************************************/
2/* */
3/* coptsub.h */
4/* */
5/* Optimize subtraction sequences */
6/* */
7/* */
8/* */
9/* (C) 2001-2006, 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#ifndef COPTSUB_H
37#define COPTSUB_H
38
39
40
41/* cc65 */
42#include "codeseg.h"
43
44
45
46/*****************************************************************************/
47/* Optimize subtractions */
48/*****************************************************************************/
49
50
51
52unsigned OptSub1 (CodeSeg* S);
53/* Search for the sequence
54**
55** sbc ...
56** bcs L
57** dex
58** L:
59**
60** and remove the handling of the high byte if X is not used later.
61*/
62
63unsigned OptSub2 (CodeSeg* S);
64/* Search for the sequence
65**
66** lda xx
67** sec
68** sta tmp1
69** lda yy
70** sbc tmp1
71** sta yy
72**
73** and replace it by
74**
75** sec
76** lda yy
77** sbc xx
78** sta yy
79*/
80
81unsigned OptSub3 (CodeSeg* S);
82/* Search for a call to decaxn and replace it by an 8 bit sub if the X register
83** is not used later.
84*/
85
86
87
88/* End of coptsub.h */
89
90#endif
91