TonBERRY/micropython
3
0
Fork 0
Code Pull Requests Activity

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

Browse Source 
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.
This commit is contained in:
Damien George
2017-06-09 13:31:57 +10:00
parent 4352b944d2
commit a8a5d1e8c8
5 changed files with 28 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
py/objgenerator.c
View File

@@ -54,12 +54,9 @@ STATIC mp_obj_t gen_wrap_call(mp_obj_t self_in, size_t n_args, size_t n_kw, cons
mp_obj_fun_bc_t *self_fun = (mp_obj_fun_bc_t*)self->fun;
assert(self_fun->base.type == &mp_type_fun_bc);
// get start of bytecode
const byte *ip = self_fun->bytecode;
// bytecode prelude: get state size and exception stack size
mp_uint_t n_state = mp_decode_uint(&ip);
mp_uint_t n_exc_stack = mp_decode_uint(&ip);
size_t n_state = mp_decode_uint_value(self_fun->bytecode);
size_t n_exc_stack = mp_decode_uint_value(mp_decode_uint_skip(self_fun->bytecode));
// allocate the generator object, with room for local stack and exception stack
mp_obj_gen_instance_t *o = m_new_obj_var(mp_obj_gen_instance_t, byte,