92 lines
2.3 KiB
C++
92 lines
2.3 KiB
C++
/** @file VirtualSchematikaMachine.hpp
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*
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* @author Roland Conybare, Jan 2026
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**/
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#pragma once
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#include "VsmInstr.hpp"
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#include <xo/expression2/Expression.hpp>
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#include <xo/gc/GCObject.hpp>
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namespace xo {
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namespace scm {
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/** @class VirtualSchematikaMachine
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* @brief virtual machine for schematika
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**/
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class VirtualSchematikaMachine {
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public:
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// will be DArenaVector<obj<StackFrame>> probably
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using Stack = void *;
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using AGCObject = xo::mm::AGCObject;
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public:
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VirtualSchematikaMachine();
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/** borrow calling thread to run indefinitely,
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* until halt instruction
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**/
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void run();
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/** execute vsm instruction in @ref pc_.
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* @retval instruction count. 1 unless pc_ is halt.
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**/
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bool execute_one();
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private:
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/** Require:
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* - expression in @ref expr_
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**/
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void _do_eval_op();
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/** evaluate a constant expression
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* Require:
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* - expression in @ref expr_
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**/
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void _do_eval_constant_op();
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/** evaluate a define-expression
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* Require:
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* - expression in @ref expr_
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**/
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void _do_eval_define_op();
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/** evaluate a variable expression
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* Require:
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* - expression in @ref expr_
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**/
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void _do_eval_variable_op();
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private:
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/*
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* Some registers are preserved by evaluation:
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* stack_
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* cont_
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*
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* Other registers are not preserved
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* pc_
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* expr_
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* value_
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*/
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/** program counter **/
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VsmInstr pc_ = VsmInstr::halt();
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#ifdef NOT_YET
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/** stack pointer **/
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Stack stack_;
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#endif
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/** expression register **/
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obj<AExpression> expr_;
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/** result register **/
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obj<AGCObject> value_;
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/** continuation register **/
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VsmInstr cont_ = VsmInstr::halt();
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};
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} /*namespace scm*/
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} /*namespace xo*/
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/* end VirtualSchematikaMachine.hpp */
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