There are memory regions that are mapped to the same physical memory - https://psx-spx.consoledev.net/memorymap/

I worked on the Metal Gear Solid port from PSX to PC, and Konami programmers chose a wild trick to store how the "C4" bomb was planted - either on the wall, or on the ground.

Essentially the pointer pointed to the same physical memory address, but if it was planted on the wall (or on the ground, I forgot) - then it was OR-ing it with 80000000h or was A0000000h - or maybe something else - lol was long time ago.

It was fun porting this on PC, and right now I don't even remember what I did exactly - hahaha

This is great, but it was originally published in 2019. See the past discussions in 2020: https://news.ycombinator.com/item?id=22932134 (114 comments) and 2021: https://news.ycombinator.com/item?id=27576902 (114 comments also).

Love Copetti. Even as someone who is not particularly knowledgeable of everything he’s talking about, I I really enjoy thumbing through his writing and diagrams. There’s just something really fun about trying to understand what is going on under the hood with these machines, especially fifth and sixth generation consoles

Executing the instruction after the jump seemed mental, but after a few days it was second nature. N64 had related issue: had to find an instruction to put between two multiplies. If the first multiple multiplied by zero or otherwise finished in two cycles, the CPU would freeze if the next instruction was also a multiply.

What a beautifully designed website. Everything is thoughtfully set-up and well placed. A great example of a well curated digital garden. It feels well kept and very human crafted.

These articles are always excellent.

PS1 games do not hold up so good, but PS2 games uprezzed to 1440p-4k are basically perfect imo.

Hey all, I posted this as I'm currently working on a PS1-related project that I hope to release soon.

Does anyone have recommendations for a PS1 web/js/wasm emulator? PCSX-Redux [0] has been great on desktop, and DuckStation [1] as well.

I found a few js/emscripten efforts, but if anyone has a rec, I'd appreciate it. Thanks!

[0] https://github.com/grumpycoders/pcsx-redux/

[1] https://duckstation.org/

I love a pre-Claude article

Did read this years ago and read it today again. Just so happy that there are people producing such quality work. Even if I personally don't know much about any of it, I still find myself being totally sucked in while reading.

The architecture which made me fall in love with RISC (or "load-store" if you prefer) and see the error of my ways with x86 (insert your derogatory term here).

The PS1 architecture is fascinating - it will also reveal why PS1 games have such a unique, recognizable style that games are trying to recreate nowadays.

Why did I think the XA decompression happened in the CD-ROM unit rather than the SPU?

They should start teaching about plash speed routers in schools.

I love his work. I bought one of his books recently :)

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