https://github.com/nmeum/riscv-utils

Scheme utility procedures for the RISC-V instruction set architecture
https://github.com/nmeum/riscv-utils

r7rs risc-v riscv

Last synced: about 1 month ago
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Scheme utility procedures for the RISC-V instruction set architecture

• Host: GitHub
• URL: https://github.com/nmeum/riscv-utils
• Owner: nmeum
• License: gpl-3.0
• Created: 2020-08-15T12:33:01.000Z (over 4 years ago)
• Default Branch: master
• Last Pushed: 2020-08-29T22:00:45.000Z (over 4 years ago)
• Last Synced: 2024-11-06T07:12:16.409Z (3 months ago)
• Topics: r7rs, risc-v, riscv
• Language: Scheme
• Homepage:
• Size: 57.6 KB
• Stars: 5
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# riscv-utils

Scheme utility procedures for the [RISC-V][riscv website] instruction set architecture.

## Features

The feature set of provided procedures is centered around easing the

development of utilities for RISC-V (especially instruction set

simulators). Currently the following features are provided:

* `decode.scm`: Decoding of RISC-V instructions.

* `encode.scm`: Encoding of RISC-V instructions.

* `convert.scm`: Conversion from/to different representations.

* `opcodes.scm`: Constants for instruction opcodes (currently rv32i only).

## Usage

The code is supposed to be used from a Scheme REPL, no binaries are

provided. The Scheme files in the `riscv/` directory are mostly(?)

[R7RS][r7rs small] compatible. It should be possible to use them with any

standard compliant Scheme implementation which provides an

[SRFI-151][srfi-151] module. Just load the files you want to use

using `(load "riscv/.scm")` from your Scheme REPL.

If your favorite Scheme implementation is [CHICKEN][call-cc], read on.

### Example

The API is intentionally very low-level. Nonetheless, many fun things

can be done with it. The following example takes an existing `JAL`

instruction (e.g. as extracted from a `riscv32-unknown-elf-objdump -d`

output) and modifies it to jump somewhere else.

	$ csi

	> (import riscv)

	> (set! jal #x0100056f)

	> (instr-j-imm jal)

	16

	> (j-type (instr-opcode jal) (instr-rd jal) 32)

	33555823

The value `33555823` (`0x200056f`) is RISC-V machine code for a JAL

instruction holing the value `32` (instead of `16`) as a J-immediate.

This can be easily verified using:

	> (set! jal-new 33555823)

	> (instr->hex jal-new)

	"#x200056f"

	> (instr-j-imm jal-new)

	32

## Installation

In addition to standard compliant(?) Scheme source code, this repository

also contains the required files for using the code as a CHICKEN Scheme

[egg][call-cc eggs]. However, since the code is still in very early

stages of development I haven't published it as an egg yet. Nonetheless,

an egg can be built locally using:

	$ chicken-install -test

### Building without installing

If installation is not desired, build as follows:

	$ export CHICKEN_REPOSITORY_PATH="$(pwd):${CHICKEN_REPOSITORY_PATH}"

	$ chicken-install -n -test

Afterwards simply run `(import riscv)` in `csi(1)` as usual.

## License

This program is free software: you can redistribute it and/or modify it

under the terms of the GNU General Public License as published by the

Free Software Foundation, either version 3 of the License, or (at your

option) any later version.

This program is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General

Public License for more details.

You should have received a copy of the GNU General Public License along

with this program. If not, see .

[riscv website]: https://riscv.org/

[srfi-151]: https://srfi.schemers.org/srfi-151/srfi-151.html

[r7rs small]: https://small.r7rs.org/

[call-cc]: https://call-cc.org

[call-cc eggs]: https://eggs.call-cc.org/