m68kmac: Proper gc collection, perhaps.

Signed-off-by: Jeff Epler <jepler@gmail.com>

ports/m68kmac/Makefile

@@ -41,7 +41,7 @@ SRC_C = \
 SRC_C += \
 	$(BUILD)/_frozen_mpy.c \
 	shared/runtime/stdout_helpers.c \
-	shared/runtime/gchelper_generic.c \
+	shared/runtime/gchelper_native.c \
 	shared/readline/readline.c \
 	shared/runtime/pyexec.c \
 
@@ -51,15 +51,15 @@ SRC_CXX += \
 	retro/ConsoleWindow.cpp \
 	retro/InitConsole.cpp \
 
-#	shared/libc/printf.c \
+SRC_S += \
-
+	shared/runtime/gchelper_m68k.S \
-#SRC_C += shared/libc/string0.c
 
 SRC_QSTR += shared/readline/readline.c shared/runtime/pyexec.c
 
 OBJ += $(PY_CORE_O)
 OBJ += $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_CXX:.cpp=.o))
+OBJ += $(addprefix $(BUILD)/, $(SRC_S:.S=.o))
 
 all: $(BUILD)/micropython.bin
 

ports/m68kmac/README.md

@@ -18,9 +18,9 @@ To run the executable and get a basic working REPL do:
 
 ## Key TODOs
 
- * Correctly implement GC collection (stack + registers)
+ * Correctly implement stack checking
  * Add Mac API support (e.g., quickdraw, arbitrary traps)
  * Add filesystem access
  * Add the ability to run python scripts in files
- * Support larger heap
+ * Support larger heap (via split heap?)
  * Address GPL files (RetroConsole), GitHub Actions CI, and other issues that might prevent upstream inclusion.

ports/m68kmac/mpconfigport.h

@@ -14,7 +14,6 @@
 
 #define MICROPY_QSTR_EXTRA_POOL           mp_qstr_frozen_const_pool
 #define MICROPY_ENABLE_GC                 (1)
-#define MICROPY_GCREGS_SETJMP             (1)
 #define MICROPY_HELPER_REPL               (1)
 #define MICROPY_MODULE_FROZEN_MPY         (1)
 #define MICROPY_ENABLE_EXTERNAL_IMPORT    (1)

shared/runtime/gchelper.h

@@ -43,6 +43,8 @@ typedef uintptr_t gc_helper_regs_t[10];
 typedef uintptr_t gc_helper_regs_t[11]; // x19-x29
 #elif defined(__riscv) && (__riscv_xlen <= 64)
 typedef uintptr_t gc_helper_regs_t[12]; // S0-S11
+#elif defined(__m68k__)
+typedef uintptr_t gc_helper_regs_t[8]; // a0-a4/d3-d7
 #endif
 
 #endif

shared/runtime/gchelper_m68k.s

@@ -0,0 +1,42 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2024 Alessandro Gatti
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+    .global gc_helper_get_regs_and_sp
+    .type   gc_helper_get_regs_and_sp, @function
+
+gc_helper_get_regs_and_sp:
+
+    /* Store registers into the given array. */
+
+    move.w  4(%sp),%a0
+    movem.l (%a0)+, %a2-%a4/%d3-%d7
+
+    /* Return the stack pointer. */
+    move %d0, %sp
+
+    rts
+
+    .size gc_helper_get_regs_and_sp, .-gc_helper_get_regs_and_sp