Changes

Jump to: navigation, search

Gate Array

36 bytes added, 9 September
/* Interrupt generation */
When the Gate Array sends an interrupt request:
*If the interrupts were authorized at the time of the request, then bit5 of R52 is cleared (but R52 was reset to 0 anyway) and the interrupt takes place
*If interrupts are not authorized, then the R52 counter continues to increment and the interrupt remains armed (the Gate Array then maintains its INT signal). When interrupts are enabled (using the EI instruction) , bit5 of R52 is cleared and the interrupt takes place. This happens only '''after the instruction that follows EI''' (so not immediately after EI), bit5 of R52 is cleared and the interrupt takes placeas this Z80 instruction has a 1-instruction delay.
Note: On Amstrad Plus, the interrupt management system is seriously beefed up. See the [[ASIC]] wiki page.
8,299
edits