Ship a device support pack: .lcf-style linker command files, startup, and register headers for the S12/S12X family #3

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opened 2026-09-24 09:52:47 +02:00 by sid · 0 comments

sid commented

2026-09-24 09:52:47 +02:00

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CodeWarrior ships a per-device support pack for essentially the entire S12/S12X family: linker command files (.lcf) defining the memory map (REGIONS/PLACEMENT), startup code, and register definition headers. This repo has one generic newlib crt0.o and a single example linker script derived from an MC9S12C32 (tests/s12/link.ld). Users targeting other parts (e.g. MC9S12XDP512, MC9S08..., S12XS) must hand-write every memory map and startup.

Motivation

A working replacement toolchain must let users build for the actual device in their project without reverse-engineering its memory map.
CodeWarrior .lcf files are a de-facto project interchange format; being able to consume or translate them lowers migration cost.

Current state

tests/s12/link.ld: RAM @ 0x0800 (2K), ROM @ 0xC000 (16K), vectors @ 0xFF80 (MC9S12C32-like, hard-coded in the firmware build (pkgs/s12-firmware.nix)).
newlib provides a generic crt0.o and sim-valid.ld ($out/m68hc11-elf/lib/), not device-specific.
No register/peripheral header files beyond what the sim models.

Proposed scope

Define a canonical, versioned memory-map description format for this repo (a .lcf-like text format or structured .ld templates) and a tool that renders it into GNU ld scripts.
Ship memory maps, startup code, and register headers for a set of common parts (MC9S12C32, MC9S12DP256, MC9S12XDP512, MC9S12XS128, ...).
Provide s19/s28/s37 build output and a memory map report (equivalent to the CodeWarrior MAP file) as part of the normal build.

Acceptance criteria

Building the same firmware for two different supported parts changes only the device selection, not the application source.
Register headers compile for both -m68hc12 and -m9s12x.
Generated link scripts place sections exactly per the declared REGIONS, and the placement is verified in gdb-sim tests.

References

tests/s12/link.ld, tests/s12/start.s, tests/s12/vectors.c
pkgs/s12-firmware.nix
pkgs/newlib-m68hc11.nix (crt0, sim-valid.ld)

CodeWarrior ships a per-device support pack for essentially the entire S12/S12X family: linker command files (`.lcf`) defining the memory map (REGIONS/PLACEMENT), startup code, and register definition headers. This repo has one generic newlib `crt0.o` and a single example linker script derived from an MC9S12C32 (`tests/s12/link.ld`). Users targeting other parts (e.g. MC9S12XDP512, MC9S08..., S12XS) must hand-write every memory map and startup. ## Motivation - A working replacement toolchain must let users build for the actual device in their project without reverse-engineering its memory map. - CodeWarrior `.lcf` files are a de-facto project interchange format; being able to consume or translate them lowers migration cost. ## Current state - `tests/s12/link.ld`: RAM @ 0x0800 (2K), ROM @ 0xC000 (16K), vectors @ 0xFF80 (MC9S12C32-like, hard-coded in the firmware build (`pkgs/s12-firmware.nix`)). - newlib provides a generic `crt0.o` and `sim-valid.ld` (`$out/m68hc11-elf/lib/`), not device-specific. - No register/peripheral header files beyond what the sim models. ## Proposed scope - Define a canonical, versioned memory-map description format for this repo (a `.lcf`-like text format or structured `.ld` templates) and a tool that renders it into GNU ld scripts. - Ship memory maps, startup code, and register headers for a set of common parts (MC9S12C32, MC9S12DP256, MC9S12XDP512, MC9S12XS128, ...). - Provide `s19`/`s28`/`s37` build output and a memory map report (equivalent to the CodeWarrior MAP file) as part of the normal build. ## Acceptance criteria - Building the same firmware for two different supported parts changes only the device selection, not the application source. - Register headers compile for both `-m68hc12` and `-m9s12x`. - Generated link scripts place sections exactly per the declared REGIONS, and the placement is verified in `gdb-sim` tests. ## References - `tests/s12/link.ld`, `tests/s12/start.s`, `tests/s12/vectors.c` - `pkgs/s12-firmware.nix` - `pkgs/newlib-m68hc11.nix` (crt0, sim-valid.ld)

sid referenced this issue

2026-09-24 09:53:59 +02:00

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2026-09-24 09:54:32 +02:00

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sid referenced this issue

2026-09-24 09:55:03 +02:00

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