Stenzek’s new PlayStation1 emulator DuckStation is now available as a Libretro core on RetroArch! The author of this promising new PlayStation1 emulator made the core by himself and has included it in his upstream repo.

DuckStation is a totally new PlayStation 1 (aka PSX) emulator focusing on playability, speed, and long-term maintainability. Accuracy is not the main focus of the emulator, but the goal is to be as accurate as possible while maintaining performance suitable for low-end devices. “Hack” options are discouraged, the default configuration should support all playable games with only some of the enhancements having compatibility issues. A “BIOS” ROM image is required to start the emulator and to play games. You can use an image from any hardware version or region, although mismatching game regions and BIOS regions may have compatibility issues. A ROM image is not provided with the emulator for legal reasons, you should dump this from your own console using Caetla or other means. DuckStation includes hardware rendering (OpenGL, Vulkan and D3D11), upscaling and 24-bit color and a 64-bit dynarec.

It is currently available on the Libretro buildbot for the following platforms:

Windows
Linux
Android (AArch64-only)

As soon as a commit is pushed on Stenzek’s repository, the libretro buildbot will compile a new build, and it should from there be available shortly for all RetroArch users.
Features

Relatively high degree of compatibility
Has three hardware renderers: OpenGL, Vulkan, and Direct3D11
Allows you to internally upscale the resolution
Has a dynamic recompiler and cached interpreter CPU core
Ability to run PSX CDROM emulation on a separate thread, reducing frame time spikes
More in the link:

https://www.libretro.com/index.php/category/blog/