1 | /*****************************************************************************/ |
2 | /* */ |
3 | /* coptneg.h */ |
4 | /* */ |
5 | /* Optimize negation 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 | #ifndef COPTNEG_H |
37 | #define COPTNEG_H |
38 | |
39 | |
40 | |
41 | /* cc65 */ |
42 | #include "codeseg.h" |
43 | |
44 | |
45 | |
46 | /*****************************************************************************/ |
47 | /* bnega optimizations */ |
48 | /*****************************************************************************/ |
49 | |
50 | |
51 | |
52 | unsigned OptBNegA1 (CodeSeg* S); |
53 | /* Check for |
54 | ** |
55 | ** ldx #$00 |
56 | ** lda .. |
57 | ** jsr bnega |
58 | ** |
59 | ** Remove the ldx if the lda does not use it. |
60 | */ |
61 | |
62 | unsigned OptBNegA2 (CodeSeg* S); |
63 | /* Check for |
64 | ** |
65 | ** lda .. |
66 | ** jsr bnega |
67 | ** jeq/jne .. |
68 | ** |
69 | ** Adjust the conditional branch and remove the call to the subroutine. |
70 | */ |
71 | |
72 | |
73 | |
74 | /*****************************************************************************/ |
75 | /* bnegax optimizations */ |
76 | /*****************************************************************************/ |
77 | |
78 | |
79 | |
80 | unsigned OptBNegAX1 (CodeSeg* S); |
81 | /* On a call to bnegax, if X is zero, the result depends only on the value in |
82 | ** A, so change the call to a call to bnega. This will get further optimized |
83 | ** later if possible. |
84 | */ |
85 | |
86 | unsigned OptBNegAX2 (CodeSeg* S); |
87 | /* Search for the sequence: |
88 | ** |
89 | ** lda (xx),y |
90 | ** tax |
91 | ** dey |
92 | ** lda (xx),y |
93 | ** jsr bnegax |
94 | ** jne/jeq ... |
95 | ** |
96 | ** and replace it by |
97 | ** |
98 | ** lda (xx),y |
99 | ** dey |
100 | ** ora (xx),y |
101 | ** jeq/jne ... |
102 | */ |
103 | |
104 | unsigned OptBNegAX3 (CodeSeg* S); |
105 | /* Search for the sequence: |
106 | ** |
107 | ** lda xx |
108 | ** ldx yy |
109 | ** jsr bnegax |
110 | ** jne/jeq ... |
111 | ** |
112 | ** and replace it by |
113 | ** |
114 | ** lda xx |
115 | ** ora xx+1 |
116 | ** jeq/jne ... |
117 | */ |
118 | |
119 | unsigned OptBNegAX4 (CodeSeg* S); |
120 | /* Search for the sequence: |
121 | ** |
122 | ** jsr xxx |
123 | ** jsr bnega(x) |
124 | ** jeq/jne ... |
125 | ** |
126 | ** and replace it by: |
127 | ** |
128 | ** jsr xxx |
129 | ** <boolean test> |
130 | ** jne/jeq ... |
131 | */ |
132 | |
133 | |
134 | |
135 | /*****************************************************************************/ |
136 | /* negax optimizations */ |
137 | /*****************************************************************************/ |
138 | |
139 | |
140 | |
141 | unsigned OptNegAX1 (CodeSeg* S); |
142 | /* Search for a call to negax and replace it by |
143 | ** |
144 | ** eor #$FF |
145 | ** clc |
146 | ** adc #$01 |
147 | ** |
148 | ** if X isn't used later. |
149 | */ |
150 | |
151 | unsigned OptNegAX2 (CodeSeg* S); |
152 | /* Search for a call to negax and replace it by |
153 | ** |
154 | ** ldx #$FF |
155 | ** eor #$FF |
156 | ** clc |
157 | ** adc #$01 |
158 | ** bne L1 |
159 | ** inx |
160 | ** L1: |
161 | ** |
162 | ** if X is known and zero on entry. |
163 | */ |
164 | |
165 | |
166 | |
167 | /*****************************************************************************/ |
168 | /* complax optimizations */ |
169 | /*****************************************************************************/ |
170 | |
171 | |
172 | |
173 | unsigned OptComplAX1 (CodeSeg* S); |
174 | /* Search for a call to complax and replace it by |
175 | ** |
176 | ** eor #$FF |
177 | ** |
178 | ** if X isn't used later. |
179 | */ |
180 | |
181 | |
182 | |
183 | /* End of coptneg.h */ |
184 | |
185 | #endif |
186 | |