On 2/19/25 11:59, Paul Koning wrote:
> An interesting variation of that is the Philips PR8000, which has 8 general > registers (well, one of the 8 is the PC, like on the PDP11) though no stack. > But actually it has 8 sets of 8 registers, one for each processor priority > level. So an interrupt automatically preserves the previous registers, and > the interrupt handler address is simply the value found in R0 (the PC) for > that level. Similarly, the NEC V25 (µPD70320 and -322 have 8 banks of registers, keyed to the interrupt number. Each bank has a word for the saved PC and segment,so no PUSH needed. End of ISR is signified with a RETRB instruction. --Chuck
