ArmCaptiveDecoder

Program for generating an instruction decoder for Captive derived from the ARM ISA specification.

Installation and Executing

1. Install python3
2. Install the following with pip
   1. Jinja2
3. Then, clone the repo
4. Decompressed ARM spec and symlink the A64_v82A_ISA_xml_00bet3.1 directory to spec/
5. Run main.py
6. Output c++ files can be found in out/ directory

Project Structure

Scripts

General development scripts

instruction_types.awk

For determining the number of instruction types from the Captive project's decode file - obviously should not be considered a complete set.

Example

awk -f instruction_types.awk <<captive/arch/aarch64/aarch64-decode.cpp>>

end_of_block.awk

For finding all of the instructions that trigger the end of a block, so that it can be determined what property of the instructions in the XML spec files determines this.

To execute,

awk -f end_of_block.awk <<captive/arch/aarch64/aarch64-decode.cpp>> | sort | uniq | grep "true"

Src

Source Code

Disasm

A standalone disassembler that uses the generated decoder to disasemble a given ARM binary

Compile

gcc main.cpp -o decode.o -lstdc++ -Wno-c++11-extensions

Generate Decoder

The code for parsing the ISA spec's XML files, generated decoder, and outputing that as C++ code in a created root-level "out" directory

main.py

This is what parses the XML files, builds the decoder, and generates the C++ files in the /out directory

query_parsed_instruction_data.py

A simple program for querying the parsed instruction data - useful for when the output of the generated code, disassembler, or other part of the system outputs a piece of info about an instructions but not enough to aid with the debugging process e.g. the mnemonic is printed by the disassembler but the filename from which the decode is derived from is useful to know.

The command line args are explorable through the standard usage and help mechanics

Other files

All other files in this directory are modules that are called by the above scripts.

Templates

These are the files that Jinja2 uses to generated the output C++ files.

Tests

Unit tests