/*****************************************************************************/ /* */ /* coptstore.c */ /* */ /* Optimize stores */ /* */ /* */ /* */ /* (C) 2002-2012, 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. */ /* */ /*****************************************************************************/ /* cc65 */ #include "codeent.h" #include "codeinfo.h" #include "coptstore.h" /*****************************************************************************/ /* Code */ /*****************************************************************************/ static void InsertStore (CodeSeg* S, unsigned* IP, LineInfo* LI) { CodeEntry* X = NewCodeEntry (OP65_STA, AM65_ZP_INDY, "sp", 0, LI); CS_InsertEntry (S, X, (*IP)++); } unsigned OptStore1 (CodeSeg* S) /* Search for the sequence ** ** ldy #n ** jsr staxysp ** ldy #n+1 ** jsr ldaxysp ** ** and remove the useless load. */ { unsigned Changes = 0; /* Walk over the entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* L[4]; /* Get next entry */ L[0] = CS_GetEntry (S, I); /* Check for the sequence */ if (L[0]->OPC == OP65_LDY && CE_IsConstImm (L[0]) && L[0]->Num < 0xFF && !CS_RangeHasLabel (S, I+1, 3) && CS_GetEntries (S, L+1, I+1, 3) && CE_IsCallTo (L[1], "staxysp") && L[2]->OPC == OP65_LDY && CE_IsKnownImm (L[2], L[0]->Num + 1) && CE_IsCallTo (L[3], "ldaxysp")) { /* Register has already the correct value, remove the loads */ CS_DelEntries (S, I+2, 2); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptStore2 (CodeSeg* S) /* Search for a call to staxysp. If the ax register is not used later, and ** the value is constant, just use the A register and store directly into the ** stack. */ { unsigned I; unsigned Changes = 0; /* Walk over the entries */ I = 0; while (I < CS_GetEntryCount (S)) { /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Get the input registers */ const RegInfo* RI = E->RI; /* Check for the call */ if (CE_IsCallTo (E, "staxysp") && RegValIsKnown (RI->In.RegA) && RegValIsKnown (RI->In.RegX) && RegValIsKnown (RI->In.RegY) && !RegAXUsed (S, I+1)) { /* Get the register values */ unsigned char A = (unsigned char) RI->In.RegA; unsigned char X = (unsigned char) RI->In.RegX; unsigned char Y = (unsigned char) RI->In.RegY; /* Setup other variables */ CodeEntry* N; unsigned IP = I + 1; /* Insertion point */ /* Replace the store. We will not remove the loads, since this is ** too complex and will be done by other optimizer steps. */ N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (A), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); /* Check if we can store one of the other bytes */ if (A != X) { N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (X), 0, E->LI); CS_InsertEntry (S, N, IP++); } N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+1), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); /* Remove the call */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptStore3 (CodeSeg* S) /* Search for a call to steaxysp. If the eax register is not used later, and ** the value is constant, just use the A register and store directly into the ** stack. */ { unsigned I; unsigned Changes = 0; /* Walk over the entries */ I = 0; while (I < CS_GetEntryCount (S)) { /* Get next entry */ CodeEntry* E = CS_GetEntry (S, I); /* Get the input registers */ const RegInfo* RI = E->RI; /* Check for the call */ if (CE_IsCallTo (E, "steaxysp") && RegValIsKnown (RI->In.RegA) && RegValIsKnown (RI->In.RegX) && RegValIsKnown (RI->In.RegY) && RegValIsKnown (RI->In.SRegLo) && RegValIsKnown (RI->In.SRegHi) && !RegEAXUsed (S, I+1)) { /* Get the register values */ unsigned char A = (unsigned char) RI->In.RegA; unsigned char X = (unsigned char) RI->In.RegX; unsigned char Y = (unsigned char) RI->In.RegY; unsigned char L = (unsigned char) RI->In.SRegLo; unsigned char H = (unsigned char) RI->In.SRegHi; /* Setup other variables */ unsigned Done = 0; CodeEntry* N; unsigned IP = I + 1; /* Insertion point */ /* Replace the store. We will not remove the loads, since this is ** too complex and will be done by other optimizer steps. */ N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (A), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x01; /* Check if we can store one of the other bytes */ if (A == X && (Done & 0x02) == 0) { N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+1), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x02; } if (A == L && (Done & 0x04) == 0) { N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+2), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x04; } if (A == H && (Done & 0x08) == 0) { N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x08; } /* Store the second byte */ if ((Done & 0x02) == 0) { N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (X), 0, E->LI); CS_InsertEntry (S, N, IP++); N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+1), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x02; } /* Check if we can store one of the other bytes */ if (X == L && (Done & 0x04) == 0) { N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+2), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x04; } if (X == H && (Done & 0x08) == 0) { N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x08; } /* Store the third byte */ if ((Done & 0x04) == 0) { N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (L), 0, E->LI); CS_InsertEntry (S, N, IP++); N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+2), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x04; } /* Check if we can store one of the other bytes */ if (L == H && (Done & 0x08) == 0) { N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x08; } /* Store the fourth byte */ if ((Done & 0x08) == 0) { N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (H), 0, E->LI); CS_InsertEntry (S, N, IP++); N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI); CS_InsertEntry (S, N, IP++); InsertStore (S, &IP, E->LI); Done |= 0x08; } /* Remove the call */ CS_DelEntry (S, I); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptStore4 (CodeSeg* S) /* Search for the sequence ** ** sta xx ** stx yy ** lda xx ** ldx yy ** ** and remove the useless load, provided that the next insn doesn't use flags ** from the load. */ { unsigned Changes = 0; /* Walk over the entries */ unsigned I = 0; while (I < CS_GetEntryCount (S)) { CodeEntry* L[5]; /* Get next entry */ L[0] = CS_GetEntry (S, I); /* Check for the sequence */ if (L[0]->OPC == OP65_STA && (L[0]->AM == AM65_ABS || L[0]->AM == AM65_ZP) && !CS_RangeHasLabel (S, I+1, 3) && CS_GetEntries (S, L+1, I+1, 4) && L[1]->OPC == OP65_STX && L[1]->AM == L[0]->AM && L[2]->OPC == OP65_LDA && L[2]->AM == L[0]->AM && L[3]->OPC == OP65_LDX && L[3]->AM == L[1]->AM && strcmp (L[0]->Arg, L[2]->Arg) == 0 && strcmp (L[1]->Arg, L[3]->Arg) == 0 && !CE_UseLoadFlags (L[4])) { /* Register has already the correct value, remove the loads */ CS_DelEntries (S, I+2, 2); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; } unsigned OptStore5 (CodeSeg* S) /* Search for the sequence ** ** lda foo ** ldx bar ** sta something ** stx something-else ** ** and, replace it by ** ** lda bar ** sta something-else ** lda foo ** sta something ** ** if the new value of X is not used later. That replacement doesn't save any ** cycles or bytes; but, it keeps the old value of X, which may be reused later. */ { unsigned Changes = 0; unsigned I = 0; /* Walk over the entries */ while (I < CS_GetEntryCount (S)) { CodeEntry* L[4]; /* Get next entry */ L[0] = CS_GetEntry (S, I); /* Check for the sequence */ if (L[0]->OPC == OP65_LDA && !CS_RangeHasLabel (S, I+1, 3) && CS_GetEntries (S, L+1, I+1, 3) && L[1]->OPC == OP65_LDX && L[2]->OPC == OP65_STA && L[3]->OPC == OP65_STX && !RegXUsed (S, I+4)) { CodeEntry* E = CS_GetEntry (S, I+1); /* Move the high-byte code to the beginning of the sequence */ CS_MoveEntry (S, I+1, I); CS_MoveEntry (S, I+3, I+1); /* Change from the X register to the A register */ CE_ReplaceOPC (E, OP65_LDA); CE_ReplaceOPC (CS_GetEntry (S, I+1), OP65_STA); /* Move labels from the old first entry to the new first entry */ CS_MoveLabels (S, CS_GetEntry (S, I+2), E); /* Remember, we had changes */ ++Changes; } /* Next entry */ ++I; } /* Return the number of changes made */ return Changes; }