ports/sh: enable split GC

ports/sh/main.c

@@ -74,6 +74,14 @@ int main(int argc, char **argv)
     /* Initialize MicroPython */
     mp_stack_ctrl_init();
     gc_init(heap, heap + sizeof(heap));
+    // TODO: gc_add(start, end) for each area we want to allocate to
+    // fx-9860G III:
+    // * (nothing? x_x)
+    // fx-CG 50:
+    // * The entirety of _uram
+    // * The entirety of the extra VRAM
+    // * Possibly memory past 2M
+    // * (keep the OS heap for normal malloc())
     mp_init();
 
     // Start a normal REPL; will exit when ctrl-D is entered on a blank line.

ports/sh/mpconfigport.h

@@ -8,6 +8,7 @@
 /* Main features */
 #define MICROPY_ENABLE_COMPILER           (1)
 #define MICROPY_ENABLE_GC                 (1)
+#define MICROPY_GC_SPLIT_HEAP             (1)
 #define MP_ENDIANNESS_BIG                 (1)
 #define MICROPY_READER_POSIX              (1)
 #define MICROPY_ERROR_REPORTING           (MICROPY_ERROR_REPORTING_DETAILED)