User:Johnburger/Demo/Dev/PIC

There are two Priority Interrupt Controllers on the IBM PC/AT and later computers - a Master and a Slave that I've named PIC.A and PIC.B respectively.

The PICs need to be initialized to get them away from the stupid defaults, but they also need to be reconfigured as new device drivers are installed.

Demo/Dev/PIC.inc

;
; Dev/PIC.inc
;

; These are the definitions for the Priority Interrupt Controllers
Dev.PIC.A.Cmd   EQU             020h
Dev.PIC.A.Mask  EQU             021h

Dev.PIC.B.Cmd   EQU             0A0h
Dev.PIC.B.Mask  EQU             0A1h

Dev.PIC.Cmd.EOI   EQU           20h
Dev.PIC.Cmd.IRR   EQU           0Ah             ; Access Interrupt Request Register
Dev.PIC.Cmd.ISR   EQU           0Bh             ; Access In-Service Register

Dev.PIC.Cmd.Init  EQU           11h
Dev.PIC.Init.8086 EQU           01h

Dev.PIC.A.Cascade EQU           0000_0100b      ; PIC.A has slave on IRQ2
Dev.PIC.B.Cascade EQU           02h             ; PIC.B is slaved on IRQ2

Dev.PIC.A.Timer   EQU           0000_0001b
Dev.PIC.A.Key     EQU           0000_0010b
Dev.PIC.A.COM2    EQU           0000_1000b
Dev.PIC.A.COM1    EQU           0001_0000b
Dev.PIC.A.Floppy  EQU           0100_0000b
Dev.PIC.A.Printer EQU           1000_0000b

Dev.PIC.B.RTC     EQU           0000_0001b
Dev.PIC.B.Mouse   EQU           0001_0000b
Dev.PIC.B.IDE0    EQU           0100_0000b
Dev.PIC.B.IDE1    EQU           1000_0000b