py: Add object repr "C", where 30-bit floats are stuffed in obj word.
This new object representation puts floats into the object word instead
of on the heap, at the expense of reducing their precision to 30 bits.
It only makes sense when the word size is 32-bits.
diff --git a/py/smallint.h b/py/smallint.h
index 19b5209..d9e53ee 100644
--- a/py/smallint.h
+++ b/py/smallint.h
@@ -32,7 +32,7 @@
// Functions for small integer arithmetic
// In SMALL_INT, next-to-highest bits is used as sign, so both must match for value in range
-#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A
+#if MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_A || MICROPY_OBJ_REPR == MICROPY_OBJ_REPR_C
#define MP_SMALL_INT_MIN ((mp_int_t)(((mp_int_t)WORD_MSBIT_HIGH) >> 1))
#define MP_SMALL_INT_FITS(n) ((((n) ^ ((n) << 1)) & WORD_MSBIT_HIGH) == 0)