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 | |
52 | unsigned 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 | |
63 | unsigned 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 | |
81 | unsigned 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 | |