/*****************************************************************************/ /* */ /* coptind.h */ /* */ /* Environment independent low level optimizations */ /* */ /* */ /* */ /* (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 */ /* warranty. In no event will the authors be held liable for any damages */ /* arising from the use of this software. */ /* */ /* Permission is granted to anyone to use this software for any purpose, */ /* including commercial applications, and to alter it and redistribute it */ /* freely, subject to the following restrictions: */ /* */ /* 1. The origin of this software must not be misrepresented; you must not */ /* claim that you wrote the original software. If you use this software */ /* in a product, an acknowledgment in the product documentation would be */ /* appreciated but is not required. */ /* 2. Altered source versions must be plainly marked as such, and must not */ /* be misrepresented as being the original software. */ /* 3. This notice may not be removed or altered from any source */ /* distribution. */ /* */ /*****************************************************************************/ #ifndef COPTIND_H #define COPTIND_H /* cc65 */ #include "codeseg.h" /*****************************************************************************/ /* 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) */ 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. */ 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. */ 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 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. */ 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