MICROPY_PERSISTENT_CODE discussion

[jickster]

mpconfig.h

Code: Select all

// Whether generated code can persist independently of the VM/runtime instance
// This is enabled automatically when needed by other features
#ifndef MICROPY_PERSISTENT_CODE
#define MICROPY_PERSISTENT_CODE (MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE || MICROPY_MODULE_FROZEN_MPY)
#endif

Please explain Whether generated code can persist independently of the VM/runtime instance

Doesn't all code persist independently? I don't get it.

[pythoncoder]

I suggest you read http://docs.micropython.org/en/latest/p ... ained.html in particular the references to frozen bytecode.

[pfalcon]

Doesn't all code persist independently? I don't get it.

What's exactly causing confusion? When someone tells you "yellow sun", they don't imply that there's also a green sun.

[jickster]

Doesn't all code persist independently? I don't get it.

What's exactly causing confusion? When someone tells you "yellow sun", they don't imply that there's also a green sun.

I read the link. Nothing says anything about code persisting or not.


Sent from my iPhone using Tapatalk

[jickster]

Doesn't all code persist independently? I don't get it.

What's exactly causing confusion? When someone tells you "yellow sun", they don't imply that there's also a green sun.

I don't know what "persist" means in this case.

The commit says

py: Add MICROPY_PERSISTENT_CODE so code can persist beyond the runtime.
Main changes when MICROPY_PERSISTENT_CODE is enabled are:

- qstrs are encoded as 2-byte fixed width in the bytecode
- all pointers are removed from bytecode and put in const_table (this
includes const objects and raw code pointers)

Ultimately this option will enable persistence for not just bytecode but
also native code.

My question is: what does it mean for code to NOT persist?
If it's located on flash because it's frozen . . . isn't it by default persisted?

Obviously a slightly different definition of "persist" is being used that I'm missing.

[jickster]

Doesn't all code persist independently? I don't get it.

What's exactly causing confusion? When someone tells you "yellow sun", they don't imply that there's also a green sun.

I tried to mpy-cross the following code

Code: Select all

import pyb

# print("Executing main.py")

def norm_add(a,b):
	return (a+b)

@micropython.native
def native_add(a,b):
	return (a+b)

ledObj = pyb.LED(1)
ledObj.toggle()

c = native_add(32,4532)

d = norm_add(c,123)

but I got the error

ValueError: can only save bytecode

Why does this happen?

[Roberthh]

Functions decorated as @micropython.native, @micropython.viper or @micropython.asm_thumb are compiled into native machine code. Frozen bytecode must only contain ... bytecode, not machine code.

[jickster]

Functions decorated as @micropython.native, @micropython.viper or @micropython.asm_thumb are compiled into native machine code. Frozen bytecode must only contain ... bytecode, not machine code.

Cross-referencing my other post, viewtopic.php?f=3&t=4014&p=22999#p22999 I finally understand that @micropython.native code doesn't persist "outside of VM" . . . FINALLY