feat: drop Mach-O and macOS support, Linux-only

README.md

@@ -28,7 +28,7 @@ gasm profile  show basic-block structure of functions
 > **Status: Phase 4 — done, Phase 5 underway.**  Phase 1 (the language
 > foundation, linter, formatter and language server) shipped in v0.1.0;
 > Phase 2 (the standalone assembler — the full amd64 instruction set plus
-> ELF, Mach-O and GOOBJ object emission) in v0.12.0; Phase 3 (dynamic
+> ELF and GOOBJ object emission) in v0.12.0; Phase 3 (dynamic
 > analysis — JIT execution, differential testing, ABI checks and coverage
 > profiling) in v0.25.0; Phase 4 (interactive debugger — ptrace-based,
 > breakpoints, watchpoints, stepping, vector register display, named buffer
@@ -56,9 +56,13 @@ carries the traditional conditional-jump spellings (`JZ`, `JNZ`, `JA`, `JC`,
 command — `just gen` — and requires only a Go installation; the committed
 output has no runtime dependency on the toolchain.
 
-The target *architectures* above are what the toolkit analyses.  The toolkit
-itself is portable Go and builds on Linux, FreeBSD and macOS, on amd64 and
-arm64 hosts.
+## Supported Platforms
+
+The toolkit runs on Linux.  All four Linux architectures are supported as
+hosts — amd64, arm64, riscv64 and loong64 — and the release matrix
+cross-compiles the same four targets.
+
+**FreeBSD support is planned for a future release.**
 
 ## Roadmap
 
@@ -133,14 +137,14 @@ Done so far:
   stack deltas, `pcfile`, `pcline`, `pcinline`).  Verified end-to-end by
   swapping a gasm-emitted object into a `go build` in place of the
   toolchain's, linking and running — bit-identical behaviour.
-- **Object-file emission** — `gasm asm --format elf` / `--format macho`
-  writes a relocatable object (a `.text` and a `.data` section, a symbol
-  table — file-local `<>` symbols local, the rest global — and one
-  `R_X86_64_PC32` / `X86_64_RELOC_SIGNED` relocation per static-symbol
-  reference) that links with the system toolchain: external references
-  resolve against undefined symbols, file-local ones against the data
-  section.  Verified end-to-end by linking a gasm-emitted object with a C
-  driver and running it.
+- **Object-file emission** — `gasm asm --format elf` writes a relocatable
+  object (a `.text` and a `.data` section, a symbol table — file-local `<>`
+  symbols local, the rest global — and one `R_X86_64_PC32` relocation per
+  static-symbol reference) that links with the system toolchain: external
+  references resolve against undefined symbols, file-local ones against the
+  data section.  Verified end-to-end by linking a gasm-emitted object with
+  a C driver and running it.  RISC-V uses the equivalent `R_RISCV_PCREL_HI20`
+  / `R_RISCV_PCREL_LO12_I` pair for AUIPC+JAL/JALR sequences.
 - **`FP`/`SP` frame mapping** — the pseudo-registers are translated onto the
   hardware stack pointer (`x+N(FP)` → `(N+8)(SP)` for a zero frame, `(N+frame+
   16)(SP)` with a frame pointer; locals via `x-N(SP)`), and the Go-style
@@ -256,8 +260,7 @@ portable Go implementation every kernel is derived from.
     label resolution, breakpoint management via `/proc/pid/mem`, named
     buffer allocation with pattern filling (`--buf`), and an interactive REPL.
   - **Remaining:** disassembly at PC (x86asm decode), memory-write support,
-    watchpoints, source-line mapping, and multi-platform support
-    (FreeBSD/macOS ptrace variants).
+    watchpoints, and source-line mapping.
 
 ### Phase 5 — the other architectures · *in progress*
 
@@ -277,8 +280,9 @@ portable Go implementation every kernel is derived from.
   dependency, `golang.org/x/arch`, is used **only in tests** to validate the
   instruction encoder by round-trip decoding — it is never linked into the
   `gasm` binary.
-- **Portable.**  Builds and runs on Linux, FreeBSD and macOS; amd64 and arm64
-  hosts.  Latest stable Go only.
+- **Linux-only.**  Runs natively on amd64, arm64, riscv64 and loong64 Linux
+  hosts; the release matrix cross-compiles the same four targets.  Latest
+  stable Go only.
 - **No vendor lock-in.**  The integration surface is the Language Server
   Protocol and a command-line interface — both open standards.  No cloud
   service, no proprietary API, no dependence on any one editor's internals.
@@ -297,7 +301,7 @@ portable Go implementation every kernel is derived from.
 | `arch` | amd64, arm64, riscv64 and loong64 register files and instruction tables. |
 | `lint` | Conservative static checks. |
 | `format` | A canonical formatter — `gofmt` for assembly. |
-| `asm` | The standalone assembler: amd64 and RISC-V encoders, linker, object-file emitters (ELF, Mach-O, GOOBJ). |
+| `asm` | The standalone assembler: amd64 and RISC-V encoders, linker, object-file emitters (ELF, GOOBJ). |
 | `verify` | JIT execution substrate for dynamic analysis, combined ABI+fuzz differential testing (Phase 3). |
 | `debug` | Interactive ptrace debugger with GPR/YMM register display and named buffer allocation (Phase 4). |
 | `lsp` | Language Server Protocol server. |
@@ -305,9 +309,8 @@ portable Go implementation every kernel is derived from.
 | `_gen` | The generator that rebuilds the instruction tables from the Go toolchain. |
 
 See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for the design rationale and
-data flow, [`docs/ZED.md`](docs/ZED.md) for the editor-integration story, and
-[`docs/DEFERRED.md`](docs/DEFERRED.md) for design decisions deliberately
-postponed (with the analysis needed to pick them up again).
+data flow, and [`docs/DEFERRED.md`](docs/DEFERRED.md) for design decisions
+deliberately postponed (with the analysis needed to pick them up again).
 
 ## Quick start
 
@@ -353,10 +356,6 @@ binary and associate it with `.s` files.  Syntax highlighting is delivered as
 infers the target architecture from the file-name suffix
 (`_amd64.s` / `_arm64.s` / `_riscv64.s` / `_loong64.s`).
 
-Zed users should read [`docs/ZED.md`](docs/ZED.md): Zed's native highlighting
-engine (Tree-sitter, C/WASM) cannot be fed from pure Go, so the pure-Go path
-into Zed is the language server and its semantic tokens.
-
 ## Licence
 
 BSD-3-Clause — the same licence as Go itself.  See [`LICENSE`](LICENSE).