I have been asking a question in another thread about the scanline counter and one thing that is required to be done for it to work is that the I flag be removed (CLI). Now that I will be starting to write the interrupt code and may need to chain them, there is one point that is maybe not specific to the MMC3 and decided that it would be better to make a different thread about it.
When the code for an interrupt is executed, since some of them will be chained and the code is not reentrant, do you need to set the I flag at the beginning of the task to avoid another interrupt to be called (and remove the flag at the end)?
In the case of the MMC3 you have to acknowledge the IRQ, is it something common in most IRQ system? Should the acknowledgement be done at the beginning or end of the IRQ?
When the code for an interrupt is executed, since some of them will be chained and the code is not reentrant, do you need to set the I flag at the beginning of the task to avoid another interrupt to be called (and remove the flag at the end)?
In the case of the MMC3 you have to acknowledge the IRQ, is it something common in most IRQ system? Should the acknowledgement be done at the beginning or end of the IRQ?