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Kio's Virtual Instruction Compiler.

intro | invocation | preprocessor | types | functions | operators | instructions  

compiler | memory  

Compiler

The compiler converts the tokenized words from the preprocessor into an intermediate code for the assembler.

Input Data:

TODO

Output Data:

TODO

Opcodes

The compiler generates an array of opcodes. Actual opcodes are a subclass of class Opcode:

LabelOpcode

JpOpcode

AsmOpcode

VarOpcode

IvalOpcode

CallProcOpcode

ProcPtrOpcode

CallProcPtrOpcode

SwitchOpcode

ExtConstOpcode

AsmSourceOpcode

ForAllEndOpcode

The base class has an interface as follows. It provides querrying the actual opcode class and conversion into human readable text. The explicit opcode class tests are for convenience only and do not cover all possible subclasses.

class Opcode
{
    opcode_id   Oid         ()  const;
    bool        Isa         (opcode_id o) const;
    bool        IsaIval     ()  const;
    bool        IsaAsmOpcode()  const;
    bool        IsaLabel    ()  const;
    bool        IsaVar      ()  const;
    cstr        ToString    ()  const;      //  e.g.: "call foo ( int, cstr -- str )"
};

LabelOpcode

class LabelOpcode : public Opcode
{
    uint Label() const;
};

The LabelOpcode defines a label at the current code position. The assembler should not generate any code, but store the label in a manner which allows him to resolve references to this label. Labels are simple uint numbers unique and starting at 0 for each compiled file.

AsmOpcode

class AsmOpcode : public Opcode
{
    cType*  RType   ()  const;
    cType*  ArgType (uint idx) const;
    idf_id  Idf     ()  const;
    cstr    Name    ()  const;
}

The AsmOpcode is the most often generated opcode. It stores a virtual assembler opcode with information about up to 2 arguments and a return type.

Member function Idf() returns an idf_id, which is a global enumeration for all known identifiers. These are enumerated in file 'idf_id.h' and all start with a lowercase 't'. The enumeration allows for fast selection of a code generation handler with a switch statement in the assember.

Member function Name() returns the readable name for this assembler opcode. This allows to print the name of an assembler opcode if the switch statement falls through all cases.

A full list of opcodes should be listed somewhere. TODO

Opcode Overloading

class cType is the base type for all target data types throughout the compiler. The assembler must extract the types and check them in order to generate the correct code. There are many opcodes which have identical names and just work on different data types.

case tPPPEEK:
{
    cType a1 = opcodes[i].ArgType(0);
    cType rt = opcodes[i].RType();
 
    assert(rt->RefSubtype() == a1);
    static ForthAsmop o[] = { ForthPPPEEKi16, ForthPPPEEKi32, ForthPPPEEKfloat };
    zcode.append( o[(rt->RealSize()-1)/2] );
    continue;
}

The above is an example for a '++peek' funktion handler. The assertion might be omitted (but was helpful for debugging the compiler). Then a static array of 3 opcode variants is defined and the actual one picked based on the data type's size and appended to the generated code in the array named 'zcode'.

JpOpcode

The JpOpcode is based on the AsmOpcode and adds a label for a jump target:

class JpOpcode : public AsmOpcode
{
    uint Label() const;
};

Possible opcodes (idf_id's) are:

tJP

tJP_Z

tJP_NZ

tAND0

tOR1

tFORALLITEMS

tFORRANGE

tDUP2_FORRANGE

tGROW_FORRANGE

VarOpcode

class VarOpcode : public Opcode
{
    Variable*   Var         ()  const;
    style_id    Context     ()  const;
    cType*      VType       ()  const;
    uint        Stack       ()  const;
};

The VarOpcode is generated to access a local or global variable. The kind of access can be either oid_vref, oid_vget or oid_vset, which can be tested with Opcode::Oid() or Opcode::Isa(opcode_id). Getters or setters for allocted data types must also just get/set the pointer and do no memory allocation/deallocation.

oid_vref: Push a pointer to the variable

oid_vget: Peek and push the contents of the variable

oid_vset: Pop and store a value into the variable

Function Context() returns an enumeration which indicated the kind of variable:

global: global variable

member: member data in a struct

local: local variable of a function

context1: local variable of a surrounding function

context2: ...

Function Stack() returns the size of data currently on the vstack (argument stack). This can be used to access local variables via the vstack pointer instead of a local variables base pointer, saving one address register.

IvalOpcode

TODO

CallProcOpcode

TODO

ProcPtrOpcode

TODO

CallProcPtrOpcode

TODO

SwitchOpcode

TODO

ExtConstOpcode

TODO

AsmSourceOpcode

TODO

ForAllEndOpcode

TODO

Archive

	Name		Letzte Änderung		Länge
	lib-Z80-Rop/		2020-11-30 15:50		21
	lib-Z80-Vss/		2017-11-12 09:55		452
	lib/		2019-10-30 17:02		3
	Libraries/		2019-10-30 17:11		6
	OSX-Qt40/		2019-10-30 17:02		5
	OSX/		2020-09-05 12:54		6
	Source/		2019-10-30 17:02		11
	Tests/		2019-10-30 17:02		9
	LICENSE		2019-10-30 17:25		1323
	README.md		2019-10-30 17:25		288
	TODO.txt		2020-10-18 12:42		340

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