Hazumi News

Hi, everyone!

I built SHDL (Simple Hardware Description Language) as an experiment in stripping hardware description down to its absolute fundamentals.

In SHDL, there are no arithmetic operators, no implicit bit widths, and no high-level constructs. You build everything explicitly from logic gates and wires, and then compose larger components hierarchically. The goal is not synthesis or performance, but understanding: what digital systems actually look like when abstractions are removed.

SHDL is accompanied by PySHDL, a Python interface that lets you load circuits, poke inputs, step the simulation, and observe outputs. Under the hood, SHDL compiles circuits to C for fast execution, but the language itself remains intentionally small and transparent.

This is not meant to replace Verilog or VHDL. It’s aimed at: - learning digital logic from first principles - experimenting with HDL and language design - teaching or visualizing how complex hardware emerges from simple gates.

I would especially appreciate feedback on: - the language design choices - what feels unnecessarily restrictive vs. educationally valuable - whether this kind of “anti-abstraction” HDL is useful to you.

Repo: https://github.com/rafa-rrayes/SHDL

Python package: PySHDL on PyPI

To make this concrete, here are a few small working examples written in SHDL:

1. Full Adder

component FullAdder(A, B, Cin) -> (Sum, Cout) {

    x1: XOR; a1: AND;
    x2: XOR; a2: AND;
    o1: OR;

    connect {
        A -> x1.A; B -> x1.B;
        A -> a1.A; B -> a1.B;

        x1.O -> x2.A; Cin -> x2.B;
        x1.O -> a2.A; Cin -> a2.B;
        a1.O -> o1.A; a2.O -> o1.B;

        x2.O -> Sum; o1.O -> Cout;
    }

}

2. 16 bit register

# clk must be high for two cycles to store a value

component Register16(In[16], clk) -> (Out[16]) {

    >i[16]{
        a1{i}: AND;
        a2{i}: AND;
        not1{i}: NOT;
        nor1{i}: NOR;
        nor2{i}: NOR;
    }
    
    connect {
        >i[16]{
            # Capture on clk
            In[{i}] -> a1{i}.A;
            In[{i}] -> not1{i}.A;
            not1{i}.O -> a2{i}.A;
            
            clk -> a1{i}.B;
            clk -> a2{i}.B;
            
            a1{i}.O -> nor1{i}.A;
            a2{i}.O -> nor2{i}.A;
            nor1{i}.O -> nor2{i}.B;
            nor2{i}.O -> nor1{i}.B;
            nor2{i}.O -> Out[{i}];
        }
    }

}

3. 16-bit Ripple-Carry Adder

use fullAdder::{FullAdder};

component Adder16(A[16], B[16], Cin) -> (Sum[16], Cout) {

    >i[16]{ fa{i}: FullAdder; }

    connect {
        A[1] -> fa1.A;
        B[1] -> fa1.B;
        Cin -> fa1.Cin;
        fa1.Sum -> Sum[1];

        >i[2,16]{
            A[{i}] -> fa{i}.A;
            B[{i}] -> fa{i}.B;
            fa{i-1}.Cout -> fa{i}.Cin;
            fa{i}.Sum -> Sum[{i}];
        }

        fa16.Cout -> Cout;
    }
}

We’ve been working with automating coding agents in sandboxes as of late. It’s bewildering how poorly standardized and difficult to use each agent varies between each other.

We open-sourced the Sandbox Agent SDK based on tools we built internally to solve 3 problems:

1. Universal agent API: interact with any coding agent using the same API

2. Running agents inside the sandbox: Agent Sandbox provides a Rust binary that serves the universal agent API over HTTP, instead of having to futz with undocumented interfaces

3. Universal session schema: persisting sessions is always problematic, since we don’t want the source of truth for the conversation to live inside the container in a schema we don’t control

Agent Sandbox SDK has:

- Any coding agent: Universal API to interact with all agents with full feature coverage

- Server or SDK mode: Run as an HTTP server or with the TypeScript SDK

- Universal session schema: Universal schema to store agent transcripts

- Supports your sandbox provider: Daytona, E2B, Vercel Sandboxes, and more

- Lightweight, portable Rust binary: Install anywhere with 1 curl command

- OpenAPI spec: Well documented and easy to integrate

We will be adding much more in the coming weeks – would love to hear any feedback or questions.