zinc.

0012 — PlayStation: PSn00bSDK + PCSX-Redux for ps1, gsKit for ps2

Context. 0009 left ps1 as an ISA check (the fx12 runtime as a hosted Linux binary under qemu-mipsel) and ps2 text-only; both HALs had no screen. Sony’s PsyQ stays excluded (spec rule 10).

Choice.

  • --target ps1 is the console. A PS-EXE (app.exe) plus a bootable CD image (app.bin/.cue, mkpsxiso) built with PSn00bSDK v0.24: its official Linux release zip ships the mipsel-none-elf GCC 12.3 toolchain, libpsn00b and mkpsxiso, so the image downloads one pinned file (sha256) instead of building GCC. The QEMU ISA check is not kept as a second target: the emulator below runs the same conformance programs on an R3000 model with the real SDK, which covers what it checked (docker/sdk-mips is now unused). --profile ps1 on the host is unchanged.
  • Runner: PCSX-Redux headless (-cli -testmode -stdout, interpreter: its dynarec misran one executable under Docker’s x86 emulation). It boots its own OpenBIOS, so no Sony BIOS is needed anywhere; BIOS TTY output goes to stdout; a 16-bit write to 0x1f802082 ends the emulator with an exit code; an 8-bit write to 0x1f802081 runs a Lua slot (used for screenshots). The HAL checks the "PCSX" id at 0x1f802080 before touching these, so the same executable runs on hardware. PCSX-Redux has no tagged releases: the image pins a content-addressed dev build (x86_64 AppImage, extracted) by sha256; it needs glibc 2.43, hence ubuntu:26.04. DuckStation was the alternative (its duckstation-regtest dumps frames), but it needs a BIOS image and has no exit or TTY channel as direct as Redux’s debug registers.
  • Missing libc pieces are Zinc’s: PSn00bSDK has no libm and no float printf/strtod, so targets/ps1/crt_ps1.cpp implements exact shortest/toFixed/parseFloat conversions (bignum) and a small libm (series kernels, ~1-3 ulp, checked against the host libm by crt_check.cpp). Soft-float throughout (R3000 has no FPU).
  • ps2 display with gsKit (already in the ps2dev image): the rasterizer fills a CT32 texture in RAM, gsKit’s texture manager uploads it, a sprite covers the double-buffered framebuffer. Running stays manual: PCSX2 needs the user’s BIOS dump (not redistributable).
  • Target specifics live in targets/<id>/<id>.cmake, included by the generated CMakeLists through ZINC_TARGET_CMAKE; zinc run builds bake a frame budget (ZINC_FRAMES, default 60) because a console program cannot read the host environment.

Consequences. zinc test --target ps1 compares PS-EXE output with the fx12 sim oracle byte for byte (9/9, 3 skipped for unavailable modules). Rendering is the shared float rasterizer on a soft-float CPU: about 20 fps for breakout in PCSX-Redux; a fixed-point or GPU-primitive path is the upgrade. Stdout and stderr share the TTY on ps1.

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