On Thu, Apr 13, 2023, alexjlzheng@xxxxxxxxx wrote: > From: Jinliang Zheng <alexjlzheng@xxxxxxxxxxx> > > According to the hardware manual, when the Poll command is issued, the Please add "8259", i.e. "According to the 8259 hardware manual". > byte returned by the I/O read is 1 in Bit 7 when there is an interrupt, > and the highest priority binary code in Bits 2:0. The current pic > simulation code is not implemented strictly according to the above > expression. > > Fix the implementation of pic_poll_read(): > 1. Set Bit 7 when there is an interrupt > 2. Return 0 when there is no interrupt I don't think #2 is justified. The spec says: The interrupt requests are ordered in priority from 0 through 7 (0 highest). I.e. the current code enumerates the _lowest_ priority when there is no interrupt, which seems more correct than reporting the highest priority possible.
