1 | /*****************************************************************************/ |
2 | /* */ |
3 | /* coptind.h */ |
4 | /* */ |
5 | /* Environment independent low level optimizations */ |
6 | /* */ |
7 | /* */ |
8 | /* */ |
9 | /* (C) 2001-2009, 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 COPTIND_H |
37 | #define COPTIND_H |
38 | |
39 | |
40 | |
41 | /* cc65 */ |
42 | #include "codeseg.h" |
43 | |
44 | |
45 | |
46 | /*****************************************************************************/ |
47 | /* Code */ |
48 | /*****************************************************************************/ |
49 | |
50 | |
51 | |
52 | unsigned OptRTSJumps1 (CodeSeg* S); |
53 | /* Replace jumps to RTS by RTS */ |
54 | |
55 | unsigned OptRTSJumps2 (CodeSeg* S); |
56 | /* Replace long conditional jumps to RTS */ |
57 | |
58 | unsigned OptDeadJumps (CodeSeg* S); |
59 | /* Remove dead jumps (jumps to the next instruction) */ |
60 | |
61 | unsigned OptDeadCode (CodeSeg* S); |
62 | /* Remove dead code (code that follows an unconditional jump or an rts/rti |
63 | ** and has no label) |
64 | */ |
65 | |
66 | unsigned OptJumpCascades (CodeSeg* S); |
67 | /* Optimize jump cascades (jumps to jumps). In such a case, the jump is |
68 | ** replaced by a jump to the final location. This will in some cases produce |
69 | ** worse code, because some jump targets are no longer reachable by short |
70 | ** branches, but this is quite rare, so there are more advantages than |
71 | ** disadvantages. |
72 | */ |
73 | |
74 | unsigned OptRTS (CodeSeg* S); |
75 | /* Optimize subroutine calls followed by an RTS. The subroutine call will get |
76 | ** replaced by a jump. Don't bother to delete the RTS if it does not have a |
77 | ** label, the dead code elimination should take care of it. |
78 | */ |
79 | |
80 | unsigned OptJumpTarget1 (CodeSeg* S); |
81 | /* If the instruction preceeding an unconditional branch is the same as the |
82 | ** instruction preceeding the jump target, the jump target may be moved |
83 | ** one entry back. This is a size optimization, since the instruction before |
84 | ** the branch gets removed. |
85 | */ |
86 | |
87 | unsigned OptJumpTarget2 (CodeSeg* S); |
88 | /* If a bcs jumps to a sec insn or a bcc jumps to clc, skip this insn, since |
89 | ** it's job is already done. |
90 | */ |
91 | |
92 | unsigned OptJumpTarget3 (CodeSeg* S); |
93 | /* Jumps to load instructions of a register, that do already have the matching |
94 | ** register contents may skip the load instruction, since it's job is already |
95 | ** done. |
96 | */ |
97 | |
98 | unsigned OptCondBranches1 (CodeSeg* S); |
99 | /* If an immidiate load of a register is followed by a conditional jump that |
100 | ** is never taken because the load of the register sets the flags in such a |
101 | ** manner, remove the conditional branch. |
102 | */ |
103 | |
104 | unsigned OptCondBranches2 (CodeSeg* S); |
105 | /* If on entry to a "rol a" instruction the accu is zero, and a beq/bne follows, |
106 | ** we can remove the rol and branch on the state of the carry. |
107 | */ |
108 | |
109 | unsigned OptUnusedLoads (CodeSeg* S); |
110 | /* Remove loads of registers where the value loaded is not used later. */ |
111 | |
112 | unsigned OptUnusedStores (CodeSeg* S); |
113 | /* Remove stores into zero page registers that aren't used later */ |
114 | |
115 | unsigned OptDupLoads (CodeSeg* S); |
116 | /* Remove loads of registers where the value loaded is already in the register. */ |
117 | |
118 | unsigned OptStoreLoad (CodeSeg* S); |
119 | /* Remove a store followed by a load from the same location. */ |
120 | |
121 | unsigned OptTransfers1 (CodeSeg* S); |
122 | /* Remove transfers from one register to another and back */ |
123 | |
124 | unsigned OptTransfers2 (CodeSeg* S); |
125 | /* Replace loads followed by a register transfer by a load with the second |
126 | ** register if possible. |
127 | */ |
128 | |
129 | unsigned OptTransfers3 (CodeSeg* S); |
130 | /* Replace a register transfer followed by a store of the second register by a |
131 | ** store of the first register if this is possible. |
132 | */ |
133 | |
134 | unsigned OptTransfers4 (CodeSeg* S); |
135 | /* Replace a load of a register followed by a transfer insn of the same register |
136 | ** by a load of the second register if possible. |
137 | */ |
138 | |
139 | unsigned OptPushPop (CodeSeg* S); |
140 | /* Remove a PHA/PLA sequence were A is not used later */ |
141 | |
142 | unsigned OptPrecalc (CodeSeg* S); |
143 | /* Replace immediate operations with the accu where the current contents are |
144 | ** known by a load of the final value. |
145 | */ |
146 | |
147 | unsigned OptBranchDist (CodeSeg* S); |
148 | /* Change branches for the distance needed. */ |
149 | |
150 | unsigned OptIndLoads1 (CodeSeg* S); |
151 | /* Change |
152 | ** |
153 | ** lda (zp),y |
154 | ** |
155 | ** into |
156 | ** |
157 | ** lda (zp,x) |
158 | ** |
159 | ** provided that x and y are both zero. |
160 | */ |
161 | |
162 | unsigned OptIndLoads2 (CodeSeg* S); |
163 | /* Change |
164 | ** |
165 | ** lda (zp,x) |
166 | ** |
167 | ** into |
168 | ** |
169 | ** lda (zp),y |
170 | ** |
171 | ** provided that x and y are both zero. |
172 | */ |
173 | |
174 | |
175 | |
176 | /* End of coptind.h */ |
177 | |
178 | #endif |
179 | |