PDD IRQ Information Blocks (DIRQ) for OS/2 Warp V4.0 and OS/2 Warp V3.0

Pointers

IRQI field irqi_pdirqHead points to the head of a chain of associated DIRQs.
Locations
airqi locates the table of IRQI entries.

DIRQs are allocated dynamically from the kernel resident heap.

The IRQI array is a static part of the OS2KRNL load module.

VM Owners
IRQI owner id: os2krnl (0xffaa).

DIRQ owner id: intdirq (0xff78).

Format

IRQI

┌────────────────┬──────┬──────┬────┬────────────────────────────────────────┐│Field Name      │Offset│Length│Type│Description                             │
├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│irqi_pdirqHead  │+0    │4     │D   │Head of shared DD chain (0 = not set)   │
├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│irqi_usIRQNum   │+4    │2     │W   │IRQ number                              │
├────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│irqi_usFlags    │+6    │2     │W   │IRQ Flags                               │
└────────────────┴──────┴──────┴────┴────────────────────────────────────────┘

irqi_usFlags flag definitions

┌────────────────┬────────┬────────────────────────────────────────┐
│Name            │Bit Mask│Description                             │
├────────────────┼────────┼────────────────────────────────────────┤
│                │0x0003  │reserved                                │
├────────────────┼────────┼────────────────────────────────────────┤
│irqf_fVDM       │0x0004  │If set, this IRQ is a candidate for     │
│                │        │routing to a VDM, if it is not claimed  │
│                │        │by a PDD                                │
├────────────────┼────────┼────────────────────────────────────────┤
│irqf_fNPX       │0x0008  │If set, the IRQ is the NPX interrupt    │
│                │        │level                                   │
├────────────────┼────────┼────────────────────────────────────────┤
│irqf_fSharing   │0x0010  │If set, the IRQ is sharable.  If clear  │
│                │        │the IRQ can not be shared by DD.        │
├────────────────┼────────┼────────────────────────────────────────┤
│irqf_fSys       │0x0020  │If set, the IRQ is owned by the system  │
│                │        │and the handler can not be changed or   │
│                │        │removed by a device driver.  Set        │
│                │        │initially for the slave, IRQ 2.         │
├────────────────┼────────┼────────────────────────────────────────┤
│irqf_fShared    │0x0040  │If set, the IRQ can be shared by more   │
│                │        │than 1 DD.  This bit reflects the shared│
│                │        │parameter of the first dh_SetIRQ issued │
│                │        │for this level.                         │
└────────────────┴────────┴────────────────────────────────────────┘

DIRQ

┌────────────────────┬──────┬──────┬────┬────────────────────────────────────────┐
│Field Name          │Offset│Length│Type│Description                             │
├────────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│dirq_pdirqLink      │+0    │4     │D   │Next DIRQ structure in list             │
├────────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│dirq_f16pfn         │+4    │4     │D   │DD's interrupt handler                  │
├────────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│dirq_usDS           │+8    │2     │W   │DD's data segment                       │
├────────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│dirq_usIRQNum       │+a    │2     │W   │IRQ number                              │
├────────────────────┼──────┼──────┼────┼────────────────────────────────────────┤
│dirq_pdirqFreeList  │+c    │4     │D   │list of unset DIRQs                     │
└────────────────────┴──────┴──────┴────┴────────────────────────────────────────┘

---

[Back: Physical Device Driver Header (DEV) for OS/2 Warp V4.0 and OS/2 Warp V3.0]
[Next: Virtual Device Driver Entry Point Structures]