Add Sony PlayStation 1 tier 3 target

src/doc/rustc/src/SUMMARY.md

@@ -29,6 +29,7 @@
     - [\*-kmc-solid_\*](platform-support/kmc-solid.md)
     - [m68k-unknown-linux-gnu](platform-support/m68k-unknown-linux-gnu.md)
     - [mips64-openwrt-linux-musl](platform-support/mips64-openwrt-linux-musl.md)
+    - [mipsel-sony-psx](platform-support/mipsel-sony-psx.md)
     - [nvptx64-nvidia-cuda](platform-support/nvptx64-nvidia-cuda.md)
     - [riscv32imac-unknown-xous-elf](platform-support/riscv32imac-unknown-xous-elf.md)
     - [*-pc-windows-gnullvm](platform-support/pc-windows-gnullvm.md)

src/doc/rustc/src/platform-support.md

@@ -260,6 +260,7 @@ target | std | host | notes
 `mips-unknown-linux-uclibc` | ✓ |  | MIPS Linux with uClibc
 [`mips64-openwrt-linux-musl`](platform-support/mips64-openwrt-linux-musl.md) | ? |  | MIPS64 for OpenWrt Linux MUSL
 `mipsel-sony-psp` | * |  | MIPS (LE) Sony PlayStation Portable (PSP)
+[`mipsel-sony-psx`](platform-support/mipsel-sony-psx.md) | * |  | MIPS (LE) Sony PlayStation 1 (PSX)
 `mipsel-unknown-linux-uclibc` | ✓ |  | MIPS (LE) Linux with uClibc
 `mipsel-unknown-none` | * |  | Bare MIPS (LE) softfloat
 `mipsisa32r6-unknown-linux-gnu` | ? |  |

src/doc/rustc/src/platform-support/mipsel-sony-psx.md

@@ -0,0 +1,49 @@
+# mipsel-sony-psx
+
+**Tier: 3**
+
+Sony PlayStation 1 (psx)
+
+## Designated Developer
+
+* [@ayrtonm](https://github.com/ayrtonm)
+
+## Requirements
+
+This target is cross-compiled.
+It has no special requirements for the host.
+
+## Building
+
+The target can be built by enabling it for a `rustc` build:
+
+```toml
+[build]
+build-stage = 1
+target = ["mipsel-sony-psx"]
+```
+
+## Cross-compilation
+
+This target can be cross-compiled from any host.
+
+## Testing
+
+Currently there is no support to run the rustc test suite for this target.
+
+## Building Rust programs
+
+Since it is Tier 3, rust doesn't ship pre-compiled artifacts for this target.
+
+Just use the `build-std` nightly cargo feature to build the `core` and `alloc` libraries:
+```shell
+cargo build -Zbuild-std=core,alloc --target mipsel-sony-psx
+```
+
+The command above generates an ELF. To generate binaries in the PSEXE format that emulators run, you can use [cargo-psx](https://github.com/ayrtonm/psx-sdk-rs#readme):
+
+```shell
+cargo psx build
+```
+
+or use `-Clink-arg=--oformat=binary` to produce a flat binary.