X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=src%2Fcc65%2Ffunction.c;h=c30e682a63eb17dd51ce5ade0a459844e5ed207b;hb=4a667ead00c10797fb57298b3dd33c2efc6c8d3f;hp=b0269576abcb7e102e853af5d9d12cdc8fc57bf1;hpb=a96da498f559cc9e794d26924ce0fb7c81c459a0;p=cc65 diff --git a/src/cc65/function.c b/src/cc65/function.c index b0269576a..c30e682a6 100644 --- a/src/cc65/function.c +++ b/src/cc65/function.c @@ -6,9 +6,9 @@ /* */ /* */ /* */ -/* (C) 2000-2001 Ullrich von Bassewitz */ -/* Wacholderweg 14 */ -/* D-70597 Stuttgart */ +/* (C) 2000-2003 Ullrich von Bassewitz */ +/* Römerstrasse 52 */ +/* D-70794 Filderstadt */ /* EMail: uz@cc65.org */ /* */ /* */ @@ -62,12 +62,13 @@ /* Structure that holds all data needed for function activation */ struct Function { - struct SymEntry* FuncEntry; /* Symbol table entry */ - type* ReturnType; /* Function return type */ - struct FuncDesc* Desc; /* Function descriptor */ - int Reserved; /* Reserved local space */ + struct SymEntry* FuncEntry; /* Symbol table entry */ + type* ReturnType; /* Function return type */ + struct FuncDesc* Desc; /* Function descriptor */ + int Reserved; /* Reserved local space */ unsigned RetLab; /* Return code label */ int TopLevelSP; /* SP at function top level */ + unsigned RegOffs; /* Register variable space offset */ }; /* Pointer to current function */ @@ -94,6 +95,7 @@ static Function* NewFunction (struct SymEntry* Sym) F->Reserved = 0; F->RetLab = GetLocalLabel (); F->TopLevelSP = 0; + F->RegOffs = RegisterSpace; /* Return the new structure */ return F; @@ -152,7 +154,7 @@ int F_HasVoidReturn (const Function* F) int F_IsVariadic (const Function* F) /* Return true if this is a variadic function */ { - return (F->Desc->Flags & FD_OLDSTYLE) != 0; + return (F->Desc->Flags & FD_VARIADIC) != 0; } @@ -220,6 +222,108 @@ void F_AllocLocalSpace (Function* F) +int F_AllocRegVar (Function* F, const type* Type) +/* Allocate a register variable for the given variable type. If the allocation + * was successful, return the offset of the register variable in the register + * bank (zero page storage). If there is no register space left, return -1. + */ +{ + /* Allow register variables only on top level and if enabled */ + if (EnableRegVars && GetLexicalLevel () == LEX_LEVEL_FUNCTION) { + + /* Get the size of the variable */ + unsigned Size = CheckedSizeOf (Type); + + /* Do we have space left? */ + if (F->RegOffs >= Size) { + /* Space left. We allocate the variables from high to low addresses, + * so the adressing is compatible with the saved values on stack. + * This allows shorter code when saving/restoring the variables. + */ + F->RegOffs -= Size; + return F->RegOffs; + } + } + + /* No space left or no allocation */ + return -1; +} + + + +static void F_RestoreRegVars (Function* F) +/* Restore the register variables for the local function if there are any. */ +{ + const SymEntry* Sym; + + /* If we don't have register variables in this function, bail out early */ + if (F->RegOffs == RegisterSpace) { + return; + } + + /* Save the accumulator if needed */ + if (!F_HasVoidReturn (F)) { + g_save (CF_CHAR | CF_FORCECHAR); + } + + /* Get the first symbol from the function symbol table */ + Sym = F->FuncEntry->V.F.Func->SymTab->SymHead; + + /* Walk through all symbols checking for register variables */ + while (Sym) { + if (SymIsRegVar (Sym)) { + + /* Check for more than one variable */ + int Offs = Sym->V.R.SaveOffs; + unsigned Bytes = CheckedSizeOf (Sym->Type); + + while (1) { + + /* Find next register variable */ + const SymEntry* NextSym = Sym->NextSym; + while (NextSym && !SymIsRegVar (NextSym)) { + NextSym = NextSym->NextSym; + } + + /* If we have a next one, compare the stack offsets */ + if (NextSym) { + + /* We have a following register variable. Get the size */ + int Size = CheckedSizeOf (NextSym->Type); + + /* Adjacent variable? */ + if (NextSym->V.R.SaveOffs + Size != Offs) { + /* No */ + break; + } + + /* Adjacent variable */ + Bytes += Size; + Offs -= Size; + Sym = NextSym; + + } else { + break; + } + } + + /* Restore the memory range */ + g_restore_regvars (Offs, Sym->V.R.RegOffs, Bytes); + + } + + /* Check next symbol */ + Sym = Sym->NextSym; + } + + /* Restore the accumulator if needed */ + if (!F_HasVoidReturn (F)) { + g_restore (CF_CHAR | CF_FORCECHAR); + } +} + + + /*****************************************************************************/ /* code */ /*****************************************************************************/ @@ -230,8 +334,7 @@ void NewFunc (SymEntry* Func) /* Parse argument declarations and function body. */ { int HadReturn; - int IsVoidFunc; - SymEntry* LastParam; + SymEntry* Param; /* Get the function descriptor from the function entry */ FuncDesc* D = Func->V.F.Func; @@ -242,9 +345,6 @@ void NewFunc (SymEntry* Func) /* Reenter the lexical level */ ReenterFunctionLevel (D); - /* Before adding more symbols, remember the last parameter for later */ - LastParam = D->SymTab->SymTail; - /* Declare two special functions symbols: __fixargs__ and __argsize__. * The latter is different depending on the type of the function (variadic * or not). @@ -262,12 +362,25 @@ void NewFunc (SymEntry* Func) /* Function body now defined */ Func->Flags |= SC_DEF; - /* Setup register variables */ - InitRegVars (); - /* Allocate code and data segments for this function */ Func->V.F.Seg = PushSegments (Func); + /* Special handling for main() */ + if (strcmp (Func->Name, "main") == 0) { + /* Main cannot be a fastcall function */ + if (IsFastCallFunc (Func->Type)) { + Error ("`main' cannot be declared as __fastcall__"); + } + + /* If main() takes parameters, generate a forced import to a function + * that will setup these parameters. This way, programs that do not + * need the additional code will not get it. + */ + if (D->ParamCount > 0 || (D->Flags & FD_VARIADIC) != 0) { + g_importmainargs (); + } + } + /* If this is a fastcall function, push the last parameter onto the stack */ if (IsFastCallFunc (Func->Type) && D->ParamCount > 0) { @@ -277,26 +390,57 @@ void NewFunc (SymEntry* Func) CHECK ((D->Flags & FD_VARIADIC) == 0); /* Generate the push */ - if (IsTypeFunc (LastParam->Type)) { + if (IsTypeFunc (D->LastParam->Type)) { /* Pointer to function */ Flags = CF_PTR; } else { - Flags = TypeOf (LastParam->Type) | CF_FORCECHAR; + Flags = TypeOf (D->LastParam->Type) | CF_FORCECHAR; } g_push (Flags, 0); } + /* Generate function entry code if needed */ + g_enter (TypeOf (Func->Type), F_GetParamSize (CurrentFunc)); + /* If stack checking code is requested, emit a call to the helper routine */ if (CheckStack) { - g_stackcheck (); + g_stackcheck (); } - /* Generate function entry code if needed */ - g_enter (TypeOf (Func->Type), F_GetParamSize (CurrentFunc)); - /* Setup the stack */ oursp = 0; + /* Walk through the parameter list and allocate register variable space + * for parameters declared as register. Generate code to swap the contents + * of the register bank with the save area on the stack. + */ + Param = D->SymTab->SymHead; + while (Param && (Param->Flags & SC_PARAM) != 0) { + + /* Check for a register variable */ + if (SymIsRegVar (Param)) { + + /* Allocate space */ + int Reg = F_AllocRegVar (CurrentFunc, Param->Type); + + /* Could we allocate a register? */ + if (Reg < 0) { + /* No register available: Convert parameter to auto */ + CvtRegVarToAuto (Param); + } else { + /* Remember the register offset */ + Param->V.R.RegOffs = Reg; + + /* Generate swap code */ + g_swap_regvars (Param->V.R.SaveOffs, Reg, CheckedSizeOf (Param->Type)); + + } + } + + /* Next parameter */ + Param = Param->NextSym; + } + /* Need a starting curly brace */ ConsumeLCurly (); @@ -318,38 +462,24 @@ void NewFunc (SymEntry* Func) } } - /* If the function has a return type but no return statement, flag - * a warning - */ - IsVoidFunc = F_HasVoidReturn (CurrentFunc); -#if 0 - /* Does not work reliably */ - if (!F_IsVoidFunc && !HadReturn) { - Warning ("Function `%s' should return a value", Func->Name); - } -#endif - /* Output the function exit code label */ g_defcodelabel (F_GetRetLab (CurrentFunc)); /* Restore the register variables */ - RestoreRegVars (!IsVoidFunc); + F_RestoreRegVars (CurrentFunc); /* Generate the exit code */ g_leave (); - /* Eat the closing brace */ - ConsumeRCurly (); - /* Emit references to imports/exports */ EmitExternals (); - /* Cleanup register variables */ - DoneRegVars (); - /* Leave the lexical level */ LeaveFunctionLevel (); + /* Eat the closing brace */ + ConsumeRCurly (); + /* Switch back to the old segments */ PopSegments ();