Sharing variable betweed Threads

[Carpentier]

Hello,
I know that variable sharing is illegal between threads, and threads should always communicate with channels. And i know also that sharing variable between threads in XC will cause compile error except if the variable is read-only.

Anyway, it is still possible in assembler language to access any memory location from different threads. My question is specially adressed to XMOS processor experts or employee.

What append if writing a variable from a thread and reading the same variable from another thread (on the same core) in assembly language :

1) The processor become mad and lead to un unpredictable state
OR
2) The processor still work fine on other tasks but the reading of the variable is unpredictable ,
giving an intermediate value from a write in progress.
OR
3) The reading of the variable correct, ie giving the most recent value that was written at the same location by the other thread

[Ross]

C

:)

[Bianco]

He means 3 :)

[Carpentier]

Thank bianco. The previous answer was not very clear, this is good to receive help in the things i am interested about.

[ale500]

I have used shared memory from XC and assembler. And you can also do it in C. It is a restriction in XC that two or more threads cannot access the same location, unless read-only.

[Ross]

He means 3 :)

Thanks! ;)

Thank bianco. The previous answer was not very clear, this is good to receive help in the things i am interested about.

Sorry, for some reason I read the options as A,B,C, not 1,2,3! Must be working too hard ;)