111 lines
4.8 KiB
Org Mode
111 lines
4.8 KiB
Org Mode
#+title: Oreo's Virtual Machine (OVM)
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#+author: Aryadev Chavali
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#+date: 2023-10-15
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A stack based virtual machine in C11, with a dynamic register setup
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which acts as variable space. Deals primarily in bytes, doesn't make
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assertions about typing and is very simple to target.
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2024-04-16: Project will now be split into two components
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1) The runtime + base library
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2) The assembler
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This will focus each repository on separate issues and make it easier
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to organize. They will both derive from the same repositories
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i.e. I'm not making fresh repositories and just sticking the folders
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in but rather branching this repository into two different versions.
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The two versions will be hosted at:
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1) [[https://github.com/aryadev-software/avm]]
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1) [[https://github.com/aryadev-software/aal]]
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* How to build
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Requires =GNU make= and a compliant C11 compiler. Code base has been
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tested against =gcc= and =clang=, but given how the project has been
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written without use of GNU'isms (that I'm aware of) it shouldn't be an
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issue to compile using something like =tcc= or another compiler (look
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at [[file:Makefile::CC=gcc][here]] to change the compiler).
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To build everything simply run ~make~. This will build:
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+ [[file:lib/inst.c][instruction bytecode system]] which provides
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object files to target the VM
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+ [[file:vm/main.c][VM executable]] which executes bytecode
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+ [[file:asm/main.c][Assembler executable]] which assembles compliant
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assembly code to VM bytecode
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+ [[file:examples/][Assembly examples]] which provide some source code
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examples on common programs one may write. Use this to figure out
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how to write compliant assembly. Also a good test of both the VM
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and assembler.
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You may also build each component individually through the
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corresponding recipe:
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+ ~make lib~
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+ ~make vm~
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+ ~make asm~
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+ ~make examples~
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* Instructions to target the virtual machine
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You need to link with the object files for
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[[file:lib/base.c][base.c]], [[file:lib/darr.c][darr.c]] and
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[[file:lib/inst.c][inst.c]] to be able to properly target the OVM.
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The basic idea is to create some instructions via ~inst_t~,
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instantiating a ~prog_t~ structure which wraps those instructions
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(includes a header and other useful things for the runtime), then
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using ~prog_write_file~ to serialise and write bytecode to a file
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pointer.
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To execute directly compiled bytecode use the ~ovm.out~ executable on
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the bytecode file.
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For clarity, one may build ~lib~ (~make lib~) then use the resulting
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object files to link and create bytecode for the virtual machine.
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** In memory virtual machine
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Instead of serialising and writing bytecode to a file, one may instead
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serialise bytecode in memory using ~prog_write_bytecode~ which writes
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bytecode to a dynamic byte buffer, so called *in memory compilation*.
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To execute this bytecode, deserialise the bytecode into a program then
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load it into a complete ~vm_t~ structure (linking with
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[[file:vm/runtime.c][runtime.c]]).
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In fact, you may skip the process of serialising entirely. You can
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emit a ~prog_t~ structure corresponding to source code, load it
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directly into the ~vm_t~ structure, then execute. To do so is a bit
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involved, so I recommend looking at [[file:vm/main.c]]. In rough
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steps:
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+ Create a virtual machine "from scratch" (load the necessary
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components (the stack, heap and call stack) by hand)
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+ Load program into VM (~vm_load_program~)
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+ Run ~vm_execute_all~
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This is recommended if writing an interpreted language such as a Lisp,
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where on demand execution of code is more suitable.
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* Lines of code
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#+begin_src sh :results table :exports results
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wc -lwc $(find -regex ".*\.[ch]\(pp\)?")
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#+end_src
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#+RESULTS:
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| Files | Lines | Words | Bytes |
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|------------------------+-------+-------+--------|
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| ./lib/heap.h | 42 | 111 | 801 |
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| ./lib/inst.c | 516 | 1315 | 13982 |
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| ./lib/darr.c | 77 | 225 | 1757 |
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| ./lib/base.c | 107 | 306 | 2002 |
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| ./lib/inst.h | 108 | 426 | 4067 |
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| ./lib/prog.h | 176 | 247 | 2616 |
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| ./lib/base.h | 148 | 626 | 3915 |
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| ./lib/darr.h | 88 | 465 | 2697 |
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| ./lib/heap.c | 101 | 270 | 1910 |
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| ./vm/runtime.h | 301 | 780 | 7965 |
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| ./vm/runtime.c | 1070 | 3097 | 30010 |
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| ./vm/main.c | 92 | 265 | 2243 |
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| ./asm/base.hpp | 21 | 68 | 472 |
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| ./asm/lexer.cpp | 565 | 1448 | 14067 |
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| ./asm/base.cpp | 33 | 89 | 705 |
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| ./asm/parser.hpp | 82 | 199 | 1656 |
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| ./asm/parser.cpp | 42 | 129 | 1294 |
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| ./asm/lexer.hpp | 106 | 204 | 1757 |
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| ./asm/preprocesser.cpp | 218 | 574 | 5800 |
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| ./asm/preprocesser.hpp | 62 | 147 | 1360 |
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| ./asm/main.cpp | 148 | 414 | 3791 |
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|------------------------+-------+-------+--------|
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| total | 4103 | 11405 | 104867 |
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