/*****************************************************************************/
/* */
-/* coptind.h */
+/* coptind.h */
/* */
-/* Environment independent low level optimizations */
+/* Environment independent low level optimizations */
/* */
/* */
/* */
-/* (C) 2001 Ullrich von Bassewitz */
-/* Wacholderweg 14 */
-/* D-70597 Stuttgart */
-/* EMail: uz@cc65.org */
+/* (C) 2001-2009, Ullrich von Bassewitz */
+/* Roemerstrasse 52 */
+/* D-70794 Filderstadt */
+/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
+/* cc65 */
#include "codeseg.h"
/*****************************************************************************/
-/* Code */
+/* Code */
/*****************************************************************************/
+unsigned OptRTSJumps1 (CodeSeg* S);
+/* Replace jumps to RTS by RTS */
+
+unsigned OptRTSJumps2 (CodeSeg* S);
+/* Replace long conditional jumps to RTS */
+
unsigned OptDeadJumps (CodeSeg* S);
/* Remove dead jumps (jumps to the next instruction) */
unsigned OptDeadCode (CodeSeg* S);
/* Remove dead code (code that follows an unconditional jump or an rts/rti
- * and has no label)
- */
+** and has no label)
+*/
unsigned OptJumpCascades (CodeSeg* S);
/* Optimize jump cascades (jumps to jumps). In such a case, the jump is
- * replaced by a jump to the final location. This will in some cases produce
- * worse code, because some jump targets are no longer reachable by short
- * branches, but this is quite rare, so there are more advantages than
- * disadvantages.
- */
+** replaced by a jump to the final location. This will in some cases produce
+** worse code, because some jump targets are no longer reachable by short
+** branches, but this is quite rare, so there are more advantages than
+** disadvantages.
+*/
unsigned OptRTS (CodeSeg* S);
/* Optimize subroutine calls followed by an RTS. The subroutine call will get
- * replaced by a jump. Don't bother to delete the RTS if it does not have a
- * label, the dead code elimination should take care of it.
- */
+** replaced by a jump. Don't bother to delete the RTS if it does not have a
+** label, the dead code elimination should take care of it.
+*/
-unsigned OptJumpTarget (CodeSeg* S);
+unsigned OptJumpTarget1 (CodeSeg* S);
/* If the instruction preceeding an unconditional branch is the same as the
- * instruction preceeding the jump target, the jump target may be moved
- * one entry back. This is a size optimization, since the instruction before
- * the branch gets removed.
- */
-
-unsigned OptCondBranches (CodeSeg* S);
+** instruction preceeding the jump target, the jump target may be moved
+** one entry back. This is a size optimization, since the instruction before
+** the branch gets removed.
+*/
+
+unsigned OptJumpTarget2 (CodeSeg* S);
+/* If a bcs jumps to a sec insn or a bcc jumps to clc, skip this insn, since
+** it's job is already done.
+*/
+
+unsigned OptJumpTarget3 (CodeSeg* S);
+/* Jumps to load instructions of a register, that do already have the matching
+** register contents may skip the load instruction, since it's job is already
+** done.
+*/
+
+unsigned OptCondBranches1 (CodeSeg* S);
/* If an immidiate load of a register is followed by a conditional jump that
- * is never taken because the load of the register sets the flags in such a
- * manner, remove the conditional branch.
- */
+** is never taken because the load of the register sets the flags in such a
+** manner, remove the conditional branch.
+*/
+
+unsigned OptCondBranches2 (CodeSeg* S);
+/* If on entry to a "rol a" instruction the accu is zero, and a beq/bne follows,
+** we can remove the rol and branch on the state of the carry.
+*/
unsigned OptUnusedLoads (CodeSeg* S);
/* Remove loads of registers where the value loaded is not used later. */
+unsigned OptUnusedStores (CodeSeg* S);
+/* Remove stores into zero page registers that aren't used later */
+
+unsigned OptDupLoads (CodeSeg* S);
+/* Remove loads of registers where the value loaded is already in the register. */
+
+unsigned OptStoreLoad (CodeSeg* S);
+/* Remove a store followed by a load from the same location. */
+
+unsigned OptTransfers1 (CodeSeg* S);
+/* Remove transfers from one register to another and back */
+
+unsigned OptTransfers2 (CodeSeg* S);
+/* Replace loads followed by a register transfer by a load with the second
+** register if possible.
+*/
+
+unsigned OptTransfers3 (CodeSeg* S);
+/* Replace a register transfer followed by a store of the second register by a
+** store of the first register if this is possible.
+*/
+
+unsigned OptTransfers4 (CodeSeg* S);
+/* Replace a load of a register followed by a transfer insn of the same register
+** by a load of the second register if possible.
+*/
+
+unsigned OptPushPop (CodeSeg* S);
+/* Remove a PHA/PLA sequence were A is not used later */
+
+unsigned OptPrecalc (CodeSeg* S);
+/* Replace immediate operations with the accu where the current contents are
+** known by a load of the final value.
+*/
+
+unsigned OptBranchDist (CodeSeg* S);
+/* Change branches for the distance needed. */
+
+unsigned OptIndLoads1 (CodeSeg* S);
+/* Change
+**
+** lda (zp),y
+**
+** into
+**
+** lda (zp,x)
+**
+** provided that x and y are both zero.
+*/
+
+unsigned OptIndLoads2 (CodeSeg* S);
+/* Change
+**
+** lda (zp,x)
+**
+** into
+**
+** lda (zp),y
+**
+** provided that x and y are both zero.
+*/
-/* End of coptind.h */
-#endif
-
+/* End of coptind.h */
+#endif
projects / cc65 / blobdiff