Sérgio Pimenta

💻️ Rebuilding technology from scratch to understand it.
🛠️ Creating tools and content that make computer fundamentals clear and accessible.

[Sérgio Pimenta @SBMPimenta]

👉New update about my RISC-V CPU Simulator

I've redesigned the ENTIRE user interface!

What do you think? Looks much better than before?

My goal is to make bare metal programming easy to learn

Assembly programming tooling is very bare bones and archaic. I want to change that.

[Sérgio Pimenta @SBMPimenta]

The RISC-V Simulator now has an output

My goal is to make learning computer architecture intuitive and accessible:

- Visual: See every step of an instructions execution.
- Interactive: Explore how data flows through the CPU in real-time.

This is just the beginning. Stay tuned!

[Sérgio Pimenta @SBMPimenta]

@wjlroe 12GB? 😱 What matters the most if it works, inefficiencies doesn't matter 🙈

[Sérgio Pimenta @SBMPimenta]

@FroidEtCold You're welcome! This video is very interesting 🙂

[Sérgio Pimenta @SBMPimenta]

Imagine if you scale up what's inside a CPU

Watch this video and you can see the MASSIVE scale is build a computer in 1960's

UNIVAC 1108
RAM: 328KB - 1.3 MB (Expandable up to 4MB
SSD: 1.18MB - 9.44MB (Magnetic drum memory is equivalent to an SSD drive)

https://t.co/ZqU5gSZ700

[Sérgio Pimenta @SBMPimenta]

Modern CPUs are logically deterministic, but temporally non-deterministic.

You know exactly WHAT your code will do, but because of:
- Caches
- Pipelines
- Branch prediction

You never know exactly WHEN.

You know 2+2 will be 4, but the CPU decides exactly when you get to see it.

[Sérgio Pimenta @SBMPimenta]

@Oval170 And Assembly? 😅

[Sérgio Pimenta @SBMPimenta]

The difficulty in programming in Assembly comes from:

- Cognitive load
- Lack of safety nets

And other things:
- Register allocation
- Calling conventions
- Expression evaluation
- Memory management
- Optimization

I think some of this problems can be fixed! 👇

[Sérgio Pimenta @SBMPimenta]

One of the problems with Assembly is the lack of safety and context.

What about adding type safety and ownership to Assembly?

Good idea or "you are just reinventing the wheel"?

Inspired on #JSDoc #Rust #Type_Script #LLVM_IR

[Sérgio Pimenta @SBMPimenta]

CPUs are very fast, but memory aren't

That's why we have caches (L1, L2,L3) out of order execution, branch prediction

But this kills determinism

You don't know how much time it will take to execute the instructions

CPU has to add wait states

This list shows the real speed

[Sérgio Pimenta @SBMPimenta]

Fortunately there's a modern SoC that you can truly own

Baochip-1x

- "Transparent" die chip
- Open bootloader
- Mostly open RTL (you can simulate the entire chip on your computer)
- Memory Management Unit
- RISC-V 350MHz
- 2MB RAM
- 4MB Flash
- $10

[Sérgio Pimenta @SBMPimenta]

Building a computer from simple TTL chips is the ultimate form of digital sovereignty

Modern systems have hidden processors inside them like the Intel ME

They have full access to your RAM, your network card, and your screen. You cannot see them, you cannot turn them off

[Sérgio Pimenta @SBMPimenta]

Modern CPUs run hidden microcode and background tasks you will never know about

You don't own them

The Z80 and 68k gave us transparency, but production is dead.
6502 how many years will be produced?

The only way to truly own a computer today? Build it yourself from TTL chips

[Sérgio Pimenta @SBMPimenta]

✨There's something magical in 80's 8bit computers

That feeling of TOTAL understanding and ownership of the machine

One person could hold the entire system in their head

Modern PCs are unfathomable to a single human mind

Out-of-order execution, branch prediction, Intel ME 👇

[Sérgio Pimenta @SBMPimenta]

@wookash_podcast I'm one of those people. Programming for the sake of programming

[Sérgio Pimenta @SBMPimenta]

Hot take: data types don't exist in hardware.

Your CPU sees no difference between the integer 65 or the character 'A'. They're all just bits.

Every typed language (C, Rust, TypeScript) is just a human agreement about what those bits mean.

The CPU is completely indifferent.

[John Brooks @JBrooksBSI]

As an assembly programmer since 1982, it is great to see the 'shocking' power of asm coding being rediscovered

https://t.co/LianwA0JLE

[Sérgio Pimenta @SBMPimenta]

Learning how to multiply 2 numbers in a RISC-V CPU that doesn't have a multiply instruction extension (RV32M).

Came to a conclusion this algorithm is a bad idea. Need to learn Big-O notation.

This helps me to understand the real cost of bad programming practices.

[Sérgio Pimenta @SBMPimenta]

@ThePrimeagen More non developers are developing software via AI = need increase of real developers to fix the slop 😅

[Sérgio Pimenta @SBMPimenta]

My first YouTube video showing my semi-working RISC-V simulator.

My English is a bit slow, so you can play at 2x speed 😅

https://t.co/EuT35FzTCP

[Sérgio Pimenta @SBMPimenta]

@NanouuSymeon Assembly

[Sérgio Pimenta @SBMPimenta]

Fun fact: You can run ANY software on ANY computer

Whether it was built in 1980 or 2026 they are fundamentally the same

The only things separating them are SPEED and MEMORY!

Even a massive AI LLM can run on an ancient machine (if you have enough memory). It just take more time

[Sérgio Pimenta @SBMPimenta]

The RISC-V Simulator now has an output

My goal is to make learning computer architecture intuitive and accessible:

- Visual: See every step of an instructions execution.
- Interactive: Explore how data flows through the CPU in real-time.

This is just the beginning. Stay tuned!