py: Provide mp_decode_uint_skip() to help reduce stack usage.

Taking the address of a local variable leads to increased stack usage, so
the mp_decode_uint_skip() function is added to reduce the need for taking
addresses.  The changes in this patch reduce stack usage of a Python call
by 8 bytes on ARM Thumb, by 16 bytes on non-windowing Xtensa archs, and by
16 bytes on x86-64.  Code size is also slightly reduced on most archs by
around 32 bytes.

1 files changed, 1 insertions, 0 deletions

diff --git a/py/bc.h b/py/bc.h
index e8d428612..88045dc55 100644
--- a/py/bc.h
+++ b/py/bc.h
@@ -92,6 +92,7 @@ typedef struct _mp_code_state_t {
 
 mp_uint_t mp_decode_uint(const byte **ptr);
 mp_uint_t mp_decode_uint_value(const byte *ptr);
+const byte *mp_decode_uint_skip(const byte *ptr);
 
 mp_vm_return_kind_t mp_execute_bytecode(mp_code_state_t *code_state, volatile mp_obj_t inject_exc);
 mp_code_state_t *mp_obj_fun_bc_prepare_codestate(mp_obj_t func, size_t n_args, size_t n_kw, const mp_obj_t *args);