118 lines
3.0 KiB
C#
118 lines
3.0 KiB
C#
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/*
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* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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using System;
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using System.Collections.Generic;
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abstract class Opcode {
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internal Opcode()
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{
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}
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/*
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* Execute this opcode.
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*/
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internal abstract void Run(CPU cpu);
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/*
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* Resolve the target (word reference) for this opcode.
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*/
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internal virtual void ResolveTarget(Word target)
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{
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throw new Exception("Not a call opcode");
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}
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/*
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* Resolve the jump offset for this opcode. Displacement is
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* relative to the address of the opcode that immediately follows
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* the jump code; thus, 0 implies no jump at all.
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*/
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internal virtual void ResolveJump(int disp)
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{
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throw new Exception("Not a jump opcode");
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}
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/*
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* Get the Word that this opcode references; this can happen
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* only with "call" and "const" opcodes. For all other opcodes,
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* this method returns null.
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*/
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internal virtual Word GetReference(T0Comp ctx)
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{
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return null;
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}
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/*
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* Get the data block that this opcode references; this can happen
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* only with "const" opcodes. For all other opcodes, this method
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* returns null.
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*/
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internal virtual ConstData GetDataBlock(T0Comp ctx)
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{
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return null;
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}
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/*
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* Test whether this opcode may "fall through", i.e. execution
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* may at least potentially proceed to the next opcode.
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*/
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internal virtual bool MayFallThrough {
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get {
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return true;
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}
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}
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/*
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* Get jump displacement. For non-jump opcodes, this returns 0.
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*/
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internal virtual int JumpDisp {
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get {
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return 0;
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}
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}
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/*
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* Get stack effect for this opcode (number of elements added to
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* the stack, could be negative). For OpcodeCall, this returns
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* 0.
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*/
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internal virtual int StackAction {
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get {
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return 0;
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}
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}
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internal abstract CodeElement ToCodeElement();
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/*
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* This method is called for the CodeElement corresponding to
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* this opcode, at gcode[off]; it is used to compute actual
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* byte jump offsets when converting code to C.
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*/
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internal virtual void FixUp(CodeElement[] gcode, int off)
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{
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}
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}
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