Technical Product Specification

Table Of Contents
Intel
®
Server Board S5400SF TPS Functional Architecture
Revision 2.02
Intel order number: D92944-007
15
3.1.2 Multiple Processor Initialization
IA-32 processors have a microcode-based bootstrap processor (BSP) arbitration protocol. The
BSP starts executing from the reset vector (F000:FFF0h). A processor that does not perform the
role of BSP is referred to as an application processor (AP).
The Intel
®
5400 Memory Controller Hub Chipset (Intel
®
5400 MCH Chipset) has two processor
front-side buses (FSB), each accommodating a single dual-core or quad-core Intel
®
Xeon
®
processor. At reset, the hardware arbitration chooses one BSP from the available processor
cores per FSB. However, the BIOS power-on self-test (POST) code requires only one processor
for execution. This requires the BIOS to elect a system BSP using registers in the Intel
®
5400
MCH Chipset. The BIOS cannot guarantee which processor will be the system BSP, only that a
system BSP will be selected. In the remainder of this document, the system BSP is referred to
as the BSP.
The BSP is responsible for executing the BIOS POST and preparing the server to boot the
operating system. At boot time, the server is in virtual wire mode and the BSP alone is
programmed to accept local interrupts (INTR) driven by the programmable interrupt controller
(PIC) and non-maskable interrupt (NMI)).
As part of the boot process, the BSP wakes each AP. When awakened, an AP programs its
memory type range registers (MTRRs) to be identical to those of the BSP. All APs execute a
halt instruction with their local interrupts disabled. If the BSP determines that an AP exists that
is a lower-featured processor or that has a lower value returned by the CPUID function, the BSP
switches to the lowest-featured processor in the server. The system management mode (SMM)
handler expects all processors to respond to an SMI.
3.1.3 Enhanced Intel SpeedStep
®
Technology
Enhanced Intel SpeedStep
®
Technology helps reduce average system power consumption and
potentially improves system acoustics by allowing the system to dynamically adjust processor
voltage and core frequency.
3.1.4 Intel
®
Extended Memory 64 Technology (Intel
®
EM64T)
Intel
®
Xeon
®
processors support Intel
®
Extended Memory 64 Technology (EM64T). Intel
®
64
architecture delivers 64-bit computing on server platforms when combined with supporting
software. Intel
®
64 architecture improves the performance by allowing systems to address more
than 4 gigabytes (GB) of both virtual and physical memory.
The following table identifies the three Intel
®
EM64T operating modes.
Table 4. Intel
®
EM64T Operating Modes
Legacy Mode Compatibility Mode 64-Bit Mode
32-bit operating system
32-bit applications
32-bit drivers
64-bit operating system
32-bit applications
64-bit drivers
4 GB address space
GPRs are 32-bit
64-bit operating system
64-bit applications
64-bit drivers
64-bit flat virtual address space
GPRs are 64-bit