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Closeup of an Intel 8259A IRQ chip from a PC XT. Pinout. The Intel 8259 is a programmable interrupt controller (PIC) designed for the Intel 8085 and 8086 microprocessors. The initial part was 8259, a later A suffix version was upward compatible and usable with the 8086 or 8088 processor.
IRQs 0 to 7 are managed by one Intel 8259 PIC, and IRQs 8 to 15 by a second Intel 8259 PIC. The first PIC, the master, is the only one that directly signals the CPU. The second PIC, the slave, instead signals to the master on its IRQ 2 line, and the master passes the signal on to the CPU.
In modern times, this is not included as a separate chip in an x86 PC, but rather as part of the motherboard's southbridge chipset. [2] In other cases, it has been replaced by the newer Advanced Programmable Interrupt Controllers which support more interrupt outputs and more flexible priority schemas.
Hardware interrupt vector numbers correspond to the hardware IRQ numbers. The exact mapping depends on how the Programmable Interrupt Controller such as Intel 8259 is programmed. [2] While Intel documents IRQs 0-7 to be mapped to vectors 0x20-0x27, IBM PC and compatibles map them to 0x08-0x0F. IRQs 8-15 are usually mapped to vectors 0x70-0x77.
Intel i945GC northbridge with Pentium Dual-Core microprocessor. This article provides a list of motherboard chipsets made by Intel, divided into three main categories: those that use the PCI bus for interconnection (the 4xx series), those that connect using specialized "hub links" (the 8xx series), and those that connect using PCI Express (the 9xx series).
The 32-bit address field is ignored. One possible implementation is to generate an interrupt acknowledge cycle on an ISA bus using a PCI/ISA bus bridge. This command is for IBM PC compatibility; if there is no Intel 8259 style interrupt controller on the PCI bus, this cycle need never be used. 0001: Special Cycle
Around the time that the Pentium 4 processor was introduced, Intel's Xeon line diverged from its line of desktop processors, which at the time was using the Pentium branding. The divergence was implemented by using different sockets; since then, the sockets for Xeon chips have tended to remain constant across several generations of implementation.
The vast majority of Intel server chips of the Xeon E3, Xeon E5, and Xeon E7 product lines support VT-d. The first—and least powerful—Xeon to support VT-d was the E5502 launched Q1'09 with two cores at 1.86 GHz on a 45 nm process. [2] Many or most Xeons subsequent to this support VT-d.