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Aryadev Chavali
2024-06-25 00:41:43 +01:00
parent a24196f236
commit 62b9b230c5
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.gitignore vendored
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@@ -3,3 +3,4 @@ build/*
TAGS
compile_commands.json
.cache/*
/ltximg/

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Makefile
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@@ -1,6 +1,6 @@
CC=gcc
VERBOSE=0
RELEASE=0
RELEASE=1
GENERAL-FLAGS:=-Wall -Wextra -Wswitch-enum -I$(shell pwd) -std=c11
DEBUG-FLAGS=-ggdb

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README.org
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#+title: Aryadev's Virtual Machine (AVM)
#+title: A Virtual Machine (AVM)
#+author: Aryadev Chavali
#+date: 2023-10-15
A virtual machine in C11, stack oriented with a dynamic register.
Deals primarily in bytes, doesn't make assertions about typing and is
very simple to target.
An exercise in making a virtual machine in C11 with both a stack and
registers.
This repository contains both a library ([[file:lib/][lib]]) to
(de)serialize bytecode and a program ([[file:vm/][vm]]) to execute
This repository contains both a shared library ([[file:lib/][lib]]) to
(de)serialise bytecode and a program ([[file:vm/][vm]]) to execute
said bytecode.
* How to build
Requires =GNU make= and a compliant C11 compiler. Code base has been
tested against =gcc= and =clang=, but given how the project has been
written without use of GNU'isms (that I'm aware of) it shouldn't be an
issue to compile using something like =tcc= or another compiler (look
at [[file:Makefile::CC=gcc][here]] to change the compiler used).
Requires =GNU make= and a compliant C11 compiler. Look
[[file:Makefile::CC=gcc][here]] to change the compiler used.
To build a release version simply run ~make all RELEASE=1~. To build
a debug version run ~make all VERBOSE=<n>~ where n can be 0, 1 or 2
depending on how verbose you want logs to standard output to be. This
will build:
To build a release version simply run ~make all~. To build a debug
version run ~make all RELEASE=0 VERBOSE=2~ which has most runtime logs
on. This will build:
+ [[file:lib/][instruction bytecode system]] which provides a shared
library for serialising and deserialising bytecode
+ [[file:vm/][VM executable]] to execute bytecode
You may also build each component individually through the
corresponding recipe:
+ ~make lib~
+ ~make vm~
* Targeting the virtual machine
Link with the shared library =libavm.so= which should be located in
the =build= folder. The general idea is to construct a ~prog_t~
structure, which consists of:
Link with the shared library =libavm.so=. The general idea is to
construct a ~prog_t~ structure, which consists of:
1) A program header with some essential properties of the program
(start address, count, etc)
2) An array of type ~inst_t~, ordered instructions for execution
2) An array of type ~inst_t~ which is an ordered set of instructions
for execution
This structure may be executed in two ways.
This structure can be executed in two ways.
** Compilation then separate execution
The ~prog_t~ structure along with a sufficiently sized buffer of bytes
(using ~prog_bytecode_size~ to get the size necessary) can be used to
call ~prog_write_bytecode~, which will populate the buffer with the
corresponding bytecode.
(~prog_bytecode_size~ gives the exact number of bytes necessary) can
be used in calling ~prog_write_bytecode~, which will populate the
buffer with the corresponding bytecode.
The buffer is written to some file then executed using the =avm=
executable. This is the classical way I expect languages to target
the virtual machine.
** In memory virtual machine
This method is more involved, introducing the virtual machine runtime
into the program itself. After constructing a ~prog_t~ structure, it
can be fit into a ~vm_t~ structure. This ~vm_t~ structure also must
have a stack, heap and call stack (look at [[file:vm/main.c]] to see
this in practice). This structure can then be used with
~vm_execute_all~ to execute the program.
This method is works by introducing the virtual machine runtime into
the program that wishes to utilise the AVM itself. After constructing
a ~prog_t~ structure, it can be fit into a ~vm_t~ structure. This
structure maintains various other components such as the stack, heap
and call stack. This structure can then be used with ~vm_execute_all~
to execute the program.
Look at [[file:vm/main.c]] to see this in practice.
Note that this skips the serialising process (i.e. the /compilation/)
by utilising the runtime directly. I could see this approach being
@@ -68,27 +60,26 @@ the ~prog_t~ can still be compiled into bytecode whenever required.
can compile an assembly-like language to bytecode.
* Lines of code
#+begin_src sh :results table :exports results
wc -lwc $(find vm/ lib/ -regex ".*\.[ch]\(pp\)?")
echo 'Files Lines Words Characters'
wc -lwc $(find vm/ lib/ -regex ".*\.[ch]\(pp\)?") | awk '{print $4 "\t" $1 "\t" $2 "\t" $3}'
#+end_src
#+RESULTS:
| Files | Lines | Words | Characters |
|------------------+-------+-------+------------|
| File | Lines | Words | Characters |
|------------------+-------+-------+------------|
| vm/runtime.h | 266 | 699 | 7250 |
| vm/main.c | 135 | 375 | 3448 |
| vm/runtime.c | 802 | 2441 | 23634 |
| vm/struct.c | 262 | 783 | 7050 |
| vm/struct.h | 69 | 196 | 1531 |
| lib/inst.c | 493 | 1215 | 13043 |
| vm/runtime.h | 327 | 872 | 9082 |
| vm/main.c | 136 | 381 | 3517 |
| vm/runtime.c | 735 | 2454 | 26742 |
| vm/struct.c | 252 | 780 | 6805 |
| vm/struct.h | 74 | 204 | 1564 |
| lib/inst.c | 567 | 1369 | 14899 |
| lib/darr.h | 149 | 709 | 4482 |
| lib/inst.h | 248 | 519 | 4964 |
| lib/inst.h | 277 | 547 | 5498 |
| lib/inst-macro.h | 71 | 281 | 2806 |
| lib/heap.h | 125 | 453 | 3050 |
| lib/base.h | 190 | 710 | 4633 |
| lib/base.h | 236 | 895 | 5868 |
| lib/heap.c | 79 | 214 | 1647 |
| lib/base.c | 61 | 226 | 1583 |
| lib/base.c | 82 | 288 | 2048 |
| lib/darr.c | 76 | 219 | 1746 |
|------------------+-------+-------+------------|
| total | 3026 | 9040 | 80867 |
|------------------+-------+-------+------------|
| total | 3186 | 9666 | 89754 |