Code in tightly coupled memory

I want give just my experience on working with tightly coupled memory. I'm using TCM for an ISR and a few time critical functions. First I forgot to put the variables used by the functions in TCM also outside from SDRAM to TCM ( __attribute__ directive just as for the variables).

In my case it was necessary to disable IRQs during functio execution:

alt_irq_context context __attribute__ ((section (".onchip_ram")));
context = alt_irq_disable_all();
//time critical code
alt_irq_enable_all(context);

Apart from performance increase another benefit of transfering functions in TCM is an uninterrupted access to SDRAM for other (custom) bus masters.

Jens