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Added Opt_a_tossub for 8-bit subtraction.
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@ -1292,6 +1292,58 @@ static unsigned Opt_a_tosne (StackOpData* D)
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static unsigned Opt_a_tossub (StackOpData* D)
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/* Optimize the tossubax sequence. */
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{
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CodeEntry* X;
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/* Inline the sbc */
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D->IP = D->OpIndex+1;
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/* Must be true because of OP_RHS_LOAD */
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CHECK ((D->Rhs.A.Flags & D->Rhs.X.Flags & LI_DIRECT) != 0);
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/* sec */
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X = NewCodeEntry (OP65_SEC, AM65_IMP, 0, 0, D->OpEntry->LI);
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InsertEntry (D, X, D->IP++);
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/* Add code for low operand */
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AddOpLow (D, OP65_SBC, &D->Rhs);
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/* Do sign-extension as high-byte operation only when its result is used */
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if ((GetRegInfo (D->Code, D->IP, REG_X) & REG_X) != 0) {
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CodeLabel* L;
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CodeEntry* N;
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X = NewCodeEntry (OP65_LDX, AM65_IMM, MakeHexArg (0), 0, D->OpEntry->LI);
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InsertEntry (D, X, D->IP++);
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/* Add sign extension - N is unused now */
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N = CS_GetEntry (D->Code, D->IP);
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CHECK (N != 0);
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L = CS_GenLabel (D->Code, N);
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X = NewCodeEntry (OP65_BCS, AM65_BRA, L->Name, L, D->OpEntry->LI);
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InsertEntry (D, X, D->IP++);
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X = NewCodeEntry (OP65_DEX, AM65_IMP, 0, 0, D->OpEntry->LI);
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InsertEntry (D, X, D->IP++);
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}
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/* Rhs load entries must be removed */
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D->Rhs.X.Flags |= LI_REMOVE;
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D->Rhs.A.Flags |= LI_REMOVE;
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/* Remove the push and the call to the tossubax function */
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RemoveRemainders (D);
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/* We changed the sequence */
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return 1;
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}
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static unsigned Opt_a_tosuge (StackOpData* D)
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/* Optimize the tosgeax and tosugeax sequences */
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{
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@ -1363,6 +1415,7 @@ static const OptFuncDesc FuncRegATable[] = {
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{ "tosleax", Opt_a_tosule, REG_NONE, OP_NONE },
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{ "tosltax", Opt_a_tosult, REG_NONE, OP_NONE },
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{ "tosneax", Opt_a_tosne, REG_NONE, OP_NONE },
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{ "tossubax", Opt_a_tossub, REG_NONE, OP_RHS_REMOVE_DIRECT | OP_RHS_LOAD_DIRECT },
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{ "tosugeax", Opt_a_tosuge, REG_NONE, OP_NONE },
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{ "tosugtax", Opt_a_tosugt, REG_NONE, OP_NONE },
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{ "tosuleax", Opt_a_tosule, REG_NONE, OP_NONE },
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