Default Configurations; Discrete Apic Configurations - Intel MultiProcessor Specification

MultiProcessor Specification
Table 5-1. Default Configurations
Default Number
Config Code of CPUs
1 2
2 2
3 2
4 2
5 2
6 2
7 2
8-255 Reserved for MP future use.
The default system configurations are designed to support dual-processor systems with fixed
configurations. Systems with dynamically configurable components, for example, a uniprocessor
system with an upgrade socket for the second processor, must always generate the MP
configuration table. Failure to do so may cause the operating system to install the wrong modules
due to erroneous configuration information.

5.1 Discrete APIC Configurations

Figure 5-1 shows the default configuration for systems that use the discrete 82489 APIC. The
Intel486 processor is shown as an example; however, this configuration can also employ Pentium
processors. In Pentium processor systems, PRST is connected to INIT instead of to RESET.
5-2
Bus APIC
Type Type Variant
ISA 82489DX
EISA 82489DX Neither timer
IRQ0
chaining
EISA 82489DX
MCA 82489DX
ISA + PCI Integrated
EISA + PCI Integrated
MCA + PCI Integrated
Schematic
As in Figure 5-1, but without
EISA logic.
As in Figure 5-1, but without
nor DMA IRQ0 and IRQ13 connection to
the I/O APIC.
As in Figure 5-1.
As in Figure 5-1, but without
EISA bus logic, with inverters
before I/O APIC inputs 1-15.
As in Figure 5-2, but without
EISA logic.
As in Figure 5-2.
As in Figure 5-2, but without
EISA bus logic, with inverters
before I/O APIC inputs 1-15.
Version 1.4