Microprocessors
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2. The real address mode (also called the ‘real mode’) emulates the programming environment of
the 8086 processor, with a few extensions (such as the ability to break out of this mode). Reset
initialization places the processor into real mode.
3. The virtual 8086 mode (also called the ‘V86 mode’) is another form of 8086 emulation mode. Unlike
the real address mode, virtual 8086 mode is compatible with protection and memory management.
The processor can enter virtual 8086 mode from protected mode to run a program written for the
8086 processor, then leave virtual 8086 mode and re-enter protected mode to run programs that use
the 32-bit instruction set.
13.11.5 PowerPC RISC Microprocessors
The PowerPC family of microprocessors are high-performance superscalar RISC microprocessors
developed jointly by MOTOROLA, IBM and Apple. They are used in personal computers, workstations
and servers as well as for industrial and commercial embedded applications. Different versions of
PowerPC microprocessors include PowerPC 601, 602, 603, ec603e, 604, 604e, 620, 740, 750, 745,
755, 750CX, 750CXE, 750FX and 750X microprocessors. PowerPC 601, 602, 603, ec603e and 604 are
32-bit microprocessors with a 32-bit address bus and a 64-bit data bus. They have 32 32-bit generalpurpose registers and 32 64-bit floating-point registers. PowerPC 601 was introduced in the year 1993
for desktop PCs and low-end workstation applications. It uses 0.5 m process technology and is
available in 100 and 120 MHz clock frequency versions. PowerPC 602 was designed for graphical and
multimedia applications. PowerPC 603 was introduced in the year 1993 and was used for applications
where low power consumption was a critical requirement. It operates at 100 MHz. Its version 603e
is an embedded microprocessor operating at 300 MHz. PowerPC 604 introduced in the year 1994 is
available in different versions operating at 80, 100, 120, 133 and 250 MHz.
PowerPC 740/750 are 32-bit RISC microprocessors with special added features including a
faster memory bus (66 MHz), larger L1 caches, enhanced integer and floating-point units and
higher core frequency. PowerPC 750CX was developed by IBM using an 0.18 m copper process.
PowerPC 750FX was introduced in the year 2002 and had an operational frequency of up to 900
MHz. PowerPC 750GX introduced in the year 2004 is the latest and most powerful G3 processor
from IBM.
13.12 Pentium Series of Microprocessors
The Pentium family of processors has its roots in the Intel 486 processor and has the same instruction
set with a few additional instructions. Pentium processors have a 64-bit data bus and represent a major
step forward in personal computer CPU design. The first Pentium processors (the P5 variety) were
introduced in 1993. They were fabricated in 0.8 m bipolar complementary metal oxide semiconductor
(BiCMOS) technology. The P5 processor runs at a clock frequency of either 60 or 66 MHz and has
3.1 million transistors. The next version of the Pentium processor family was the P54 processor. The
P54 processors were fabricated in 0.6 m BiCMOS technology. The P54 was followed by P54C,
introduced in 1994, which used a 0.35 m CMOS process, as opposed to the bipolar CMOS process
used for the earlier Pentiums. The P5 operated on 5 V supply and the P54 and P54C series operated
on a 3.5 V supply voltage. All these processors had a problem in the floating-point unit. They were
followed by the P55C processor, also referred to as the Pentium MMX. It was based on the P5 core
and fabricated using the 0.35 m process. The performance of the P55C was improved over the
previous versions by doubling the level 1 CPU cache from 16 to 32 kB. Intel has retained the Pentium
trademark for naming later generations of processor architectures, which are internally quite different
557
2. The real address mode (also called the ‘real mode’) emulates the programming environment of
the 8086 processor, with a few extensions (such as the ability to break out of this mode). Reset
initialization places the processor into real mode.
3. The virtual 8086 mode (also called the ‘V86 mode’) is another form of 8086 emulation mode. Unlike
the real address mode, virtual 8086 mode is compatible with protection and memory management.
The processor can enter virtual 8086 mode from protected mode to run a program written for the
8086 processor, then leave virtual 8086 mode and re-enter protected mode to run programs that use
the 32-bit instruction set.
13.11.5 PowerPC RISC Microprocessors
The PowerPC family of microprocessors are high-performance superscalar RISC microprocessors
developed jointly by MOTOROLA, IBM and Apple. They are used in personal computers, workstations
and servers as well as for industrial and commercial embedded applications. Different versions of
PowerPC microprocessors include PowerPC 601, 602, 603, ec603e, 604, 604e, 620, 740, 750, 745,
755, 750CX, 750CXE, 750FX and 750X microprocessors. PowerPC 601, 602, 603, ec603e and 604 are
32-bit microprocessors with a 32-bit address bus and a 64-bit data bus. They have 32 32-bit generalpurpose registers and 32 64-bit floating-point registers. PowerPC 601 was introduced in the year 1993
for desktop PCs and low-end workstation applications. It uses 0.5 m process technology and is
available in 100 and 120 MHz clock frequency versions. PowerPC 602 was designed for graphical and
multimedia applications. PowerPC 603 was introduced in the year 1993 and was used for applications
where low power consumption was a critical requirement. It operates at 100 MHz. Its version 603e
is an embedded microprocessor operating at 300 MHz. PowerPC 604 introduced in the year 1994 is
available in different versions operating at 80, 100, 120, 133 and 250 MHz.
PowerPC 740/750 are 32-bit RISC microprocessors with special added features including a
faster memory bus (66 MHz), larger L1 caches, enhanced integer and floating-point units and
higher core frequency. PowerPC 750CX was developed by IBM using an 0.18 m copper process.
PowerPC 750FX was introduced in the year 2002 and had an operational frequency of up to 900
MHz. PowerPC 750GX introduced in the year 2004 is the latest and most powerful G3 processor
from IBM.
13.12 Pentium Series of Microprocessors
The Pentium family of processors has its roots in the Intel 486 processor and has the same instruction
set with a few additional instructions. Pentium processors have a 64-bit data bus and represent a major
step forward in personal computer CPU design. The first Pentium processors (the P5 variety) were
introduced in 1993. They were fabricated in 0.8 m bipolar complementary metal oxide semiconductor
(BiCMOS) technology. The P5 processor runs at a clock frequency of either 60 or 66 MHz and has
3.1 million transistors. The next version of the Pentium processor family was the P54 processor. The
P54 processors were fabricated in 0.6 m BiCMOS technology. The P54 was followed by P54C,
introduced in 1994, which used a 0.35 m CMOS process, as opposed to the bipolar CMOS process
used for the earlier Pentiums. The P5 operated on 5 V supply and the P54 and P54C series operated
on a 3.5 V supply voltage. All these processors had a problem in the floating-point unit. They were
followed by the P55C processor, also referred to as the Pentium MMX. It was based on the P5 core
and fabricated using the 0.35 m process. The performance of the P55C was improved over the
previous versions by doubling the level 1 CPU cache from 16 to 32 kB. Intel has retained the Pentium
trademark for naming later generations of processor architectures, which are internally quite different