The ISA as an API You Cannot Extend
June 18, 2021

A fixed instruction set gives software developers a polished interface to a machine they cannot change. Brian Greenforest compares it to building a major web product with permission to call an API but no permission to write server-side code.

Verilog removes that restriction. It lets programmers define the parallel circuits, state, and interfaces that their application actually needs.

The ISA Fixes the Shape of Every Request

Software can combine instructions endlessly, yet each operation still passes through the processor’s documented vocabulary, register model, memory hierarchy, and control flow.

Custom hardware moves the application’s structure into the machine. Reactive paths run together, data stays near the logic that uses it, and the design pays only for the mechanisms it needs.

Every Programmer Should Meet the Fabric

Learning Verilog changes how a developer sees loops, functions, state, timing, and concurrency. Even when the final product uses a CPU, the hardware model reveals the cost and opportunity behind every abstraction.

Build one Verilog design, simulate its waveform, and carry that physical understanding back into software—or forward into a fully reconfigurable system.

Originally posted on LinkedIn

Brian Greenforest · (2021-06-18 17:11:02 UTC)

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Imagine that there is a capability to call a web service. Anytime, anywhere, with a perfect documentation. And you are trying to make a LARGE commercial project. But you are NOT ALLOWED to write ANY server-side source code. That's what using existing ISA (machine instructions) feels like when you are only ALLOWED to write software. As a software development engineer who writes programs for microprocessors and commercial CPUs and servers for almost three decades, I state that it's a quite of a "mental trap"... Any smart talented software engineer at some day may realize she can't write software anymore and BADLY WANTS those PARALLEL REACTIVE RECONFIGURABLE circuits. I strongly believe that EVERY PROGRAMMER in any language MUST learn and practice Verilog!

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OMG glad you've asked! Of course! Harel statecharts, one-hot encoding, semigroups... all this suitable for direct implementation in RTL of course.

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