Some progress

cmake/toolchains/saturn.cmake

@@ -0,0 +1,59 @@
+# Copyright (c) 2026 Dominic Masters
+#
+# This software is released under the MIT License.
+# https://opensource.org/licenses/MIT
+#
+# CMake toolchain file for Sega Saturn (Hitachi SH-2, big-endian)
+# using the Yaul homebrew SDK.  Set YAUL_INSTALL_ROOT or the
+# YAUL_INSTALL_ROOT environment variable before invoking cmake.
+
+set(CMAKE_SYSTEM_NAME Generic)
+set(CMAKE_SYSTEM_PROCESSOR sh2)
+
+# Resolve Yaul install root
+if(NOT DEFINED YAUL_INSTALL_ROOT)
+  if(DEFINED ENV{YAUL_INSTALL_ROOT})
+    set(YAUL_INSTALL_ROOT "$ENV{YAUL_INSTALL_ROOT}"
+        CACHE PATH "Yaul SDK root" FORCE)
+  else()
+    set(YAUL_INSTALL_ROOT "/opt/yaul"
+        CACHE PATH "Yaul SDK root" FORCE)
+  endif()
+endif()
+
+# Yaul SH-2 cross-compiler prefix is sh2eb-elf (big-endian SH-2 ELF).
+# Binaries live in ${YAUL_INSTALL_ROOT}/bin/; headers/libs under
+# ${YAUL_INSTALL_ROOT}/sh2eb-elf/{include,lib}/.
+set(_YAUL_BIN "${YAUL_INSTALL_ROOT}/bin")
+
+set(CMAKE_C_COMPILER   "${_YAUL_BIN}/sh2eb-elf-gcc")
+set(CMAKE_CXX_COMPILER "${_YAUL_BIN}/sh2eb-elf-g++")
+set(CMAKE_AR           "${_YAUL_BIN}/sh2eb-elf-ar")
+set(CMAKE_RANLIB       "${_YAUL_BIN}/sh2eb-elf-ranlib")
+set(CMAKE_STRIP        "${_YAUL_BIN}/sh2eb-elf-strip")
+set(CMAKE_OBJCOPY      "${_YAUL_BIN}/sh2eb-elf-objcopy")
+set(CMAKE_LINKER       "${_YAUL_BIN}/sh2eb-elf-ld")
+
+set(CMAKE_CROSSCOMPILING TRUE)
+
+# Tell CMake not to try to run built executables
+set(CMAKE_CROSSCOMPILING_EMULATOR "" CACHE STRING "" FORCE)
+set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+
+# Sysroot — Yaul installs headers/libs under the arch-prefix subdirectory
+set(_YAUL_SYSROOT "${YAUL_INSTALL_ROOT}/sh2eb-elf")
+set(CMAKE_FIND_ROOT_PATH "${_YAUL_SYSROOT}")
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+
+# SH-2 core flags: big-endian (-mb), SH-2 ISA (-m2), no FPU
+set(_SAT_C_FLAGS "-m2 -mb -fno-builtin -fomit-frame-pointer")
+set(CMAKE_C_FLAGS_INIT   "${_SAT_C_FLAGS}")
+
+# Yaul provides its own startup code and linker script.
+# The kernel.ld script maps Saturn Work RAM (0x06000000+).
+set(_YAUL_LD "${YAUL_INSTALL_ROOT}/share/yaul/ip/kernel.ld")
+set(CMAKE_EXE_LINKER_FLAGS_INIT
+  "-T\"${_YAUL_LD}\" -Wl,--start-group -Wl,--end-group -nostartfiles")