MP系统下的三种中断模式

最新推荐文章于 2022-07-13 14:58:23 发布

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最新推荐文章于 2022-07-13 14:58:23 发布

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分类专栏： BIOS debug心得文章标签： signal system

本文链接：https://blog.youkuaiyun.com/hezp1984/article/details/5841593

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本文介绍了MP系统下的三种中断模式：PIC模式，Virtual Wire模式和Symmetric I/O模式。PIC模式与PC/AT软件兼容，通过中断模式配置寄存器（IMCR）控制中断信号来源。Virtual Wire模式中，8259A等效的PIC处理所有中断，BSP的本地APIC作为虚拟总线，通过LINTIN0传递中断。Symmetric I/O模式则需要至少一个I/O APIC，I/O中断由I/O APIC生成。

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3.6.2.1 PIC Mode
PIC Mode is software compatible with the PC/AT because it actually employs the same hardware
interrupt configuration. As Figure 3-2 illustrates, the hardware for PIC Mode bypasses the APIC
components by using an interrupt mode configuration register (IMCR). This register controls
whether the interrupt signals that reach the BSP come from the master PIC or from the local APIC.
Before entering Symmetric I/O Mode, either the BIOS or the operating system must switch out of
PIC Mode by changing the IMCR.

3.6.2.2 Virtual Wire Mode

In Virtual Wire Mode, as shown in Figure 3-3, the 8259A-equivalent PIC fields all interrupts, and
the local APIC of the BSP becomes a virtual wire, which delivers interrupts from the PIC to the
BSP via the local APIC’s local interrupt 0 (LINTIN0). The LINTIN0 pin of the local APIC is
pro