/**
** @file	pic.h
**
** @author	Warren R. Carithers
** @author	K. Reek
**
** Definitions of constants and macros for the Intel 8259 Programmable
** Interrupt Controller.
**
*/

#ifndef X86PIC_H_
#define X86PIC_H_

/*
** Our expected configuration is two PICs, with the secondary connected
** through the IRQ2 pin of the primary.
*/
/*
** Port addresses for the command port and interrupt mask register port
** for both the primary and secondary PICs.
*/
#define PIC1_CMD 0x20 // primary command
#define PIC1_DATA (PIC1_CMD + 1) // primary data / int mask register
#define PIC2_CMD 0xA0 // secondary command
#define PIC2_DATA (PIC2_CMD + 1) // secondary data / int mask register

/*
** Initialization Command Word (ICW) definitions
**
** Initialization sequence:
**    ICW1 Init command is sent to each command port.
**    ICW2 vector commands are sent to the data ports.
**    If "cascade mode" was selected, send ICW3 commands to the data ports.
**    If "need ICW4" was selected, send ICW4 commands to the data ports.
**
** Following that sequence, the PIC is ready to accept interrupts;
** it will also accept Output Command Words (OCWs) to the data ports.
**
** PIC1_* defines are intended for the primary PIC
** PIC2_* defines are intended for the secondary PIC
** PIC_* defines are sent to both PICs
*/
/*
** ICW1: initialization, send to command port
*/
#define PIC_CW1_INIT 0x10 // start initialization sequence
#define PIC_CW1_NEED4 0x01 // ICW4 will also be set
#define PIC_CW1_SINGLE 0x02 // select single (vs. cascade) mode
#define PIC_CW1_INTVAL 0x04 // set call interval to 4 (vs. 8)
#define PIC_CW1_LEVEL 0x08 // use level-triggered mode (vs. edge)

/*
** ICW2: interrupt vector base offsets, send to data port
*/
#define PIC1_CW2_VECBASE 0x20 // IRQ0 int vector number
#define PIC2_CW2_VECBASE 0x28 // IRQ8 int vector number

/*
** ICW3: secondary::primary attachment, send to data port
*/
#define PIC1_CW3_SEC_IRQ2 0x04 // bit mask: secondary is on pin 2
#define PIC2_CW3_SEC_ID 0x02 // integer: secondary id

/*
** ICW4: operating mode, send to data port
*/
#define PIC_CW4_PM86 0x01 // 8086 mode (vs. 8080/8085)
#define PIC_CW4_AUTOEOI 0x02 // do auto eoi's
#define PIC_CW4_UNBUF 0x00 // unbuffered mode
#define PIC_CW4_SEC_BUF 0x08 // put secondary in buffered mode
#define PIC_CW4_PRI_BUF 0x0C // put primary in buffered mode
#define PIC_CW4_SFNMODE 0x10 // "special fully nested" mode

/*
** Operation Control Words (OCWs)
**
** After the init sequence, can send these
*/
/*
** OCW1: interrupt mask; send to data port
*/
#define PIC_MASK_NONE 0x00 // allow all interrupts
#define PIC_MASK_NO_IRQ0 0x01 // prevent IRQ0 interrupts
#define PIC_MASK_NO_IRQ1 0x02 // prevent IRQ1 interrupts
#define PIC_MASK_NO_IRQ2 0x04 // prevent IRQ2 interrupts
#define PIC_MASK_NO_IRQ3 0x08 // prevent IRQ3 interrupts
#define PIC_MASK_NO_IRQ4 0x10 // prevent IRQ4 interrupts
#define PIC_MASK_NO_IRQ5 0x20 // prevent IRQ5 interrupts
#define PIC_MASK_NO_IRQ6 0x40 // prevent IRQ6 interrupts
#define PIC_MASK_NO_IRQ7 0x80 // prevent IRQ7 interrupts
#define PIC_MASK_ALL 0xff // prevent all interrupts

/*
** OCW2: EOI control, interrupt level; send to command port
*/
#define PIC_LVL_0 0x00 // act on IRQ level 0
#define PIC_LVL_1 0x01 // act on IRQ level 1
#define PIC_LVL_2 0x02 // act on IRQ level 2
#define PIC_LVL_3 0x03 // act on IRQ level 3
#define PIC_LVL_4 0x04 // act on IRQ level 4
#define PIC_LVL_5 0x05 // act on IRQ level 5
#define PIC_LVL_6 0x06 // act on IRQ level 6
#define PIC_LVL_7 0x07 // act on IRQ level 7

#define PIC_EOI_NON_SPEC 0x20 // non-specific EOI command
#define PIC_EOI PIC_EOI_NON_SPEC

#define PIC_EOI_SPEC 0x60 // specific EOI command
#define PIC_SEOI PIC_EOI_SPEC
#define PIC_SEOI_LVL0 (PIC_EOI_SPEC | PIC_LVL_0)
#define PIC_SEOI_LVL1 (PIC_EOI_SPEC | PIC_LVL_1)
#define PIC_SEOI_LVL2 (PIC_EOI_SPEC | PIC_LVL_2)
#define PIC_SEOI_LVL3 (PIC_EOI_SPEC | PIC_LVL_3)
#define PIC_SEOI_LVL4 (PIC_EOI_SPEC | PIC_LVL_4)
#define PIC_SEOI_LVL5 (PIC_EOI_SPEC | PIC_LVL_5)
#define PIC_SEOI_LVL6 (PIC_EOI_SPEC | PIC_LVL_6)
#define PIC_SEOI_LVL7 (PIC_EOI_SPEC | PIC_LVL_7)

#define PIC_EOI_ROT_NONSP 0xa0 // rotate on non-spec EOI cmd
#define PIC_EOI_SET_ROT_AUTO 0x80 // set "rotate in auto EOI mode"
#define PIC_EOI_CLR_ROT_AUTO 0x00 // clear "rotate in auto EOI mode"
#define PIC_EOI_ROT_SPEC 0xe0 // rotate on spec EOI cmd (+ level)
#define PIC_EOI_SET_PRIO 0xc0 // set priority (+ level)
#define PIC_EOI_NOP 0x40 // no operation

/*
** OCW3: read requests, special mask mode; send to command port
*/
#define PIC_READIRR 0x0a // read the IR register
#define PIC_READISR 0x0b // read the IS register
#define PIC_POLL 0x0c // poll
#define PIC_MASK_RESET 0x48 // reset special mask mode
#define PIC_MASK_SET 0x68 // set special mask mode

#endif