Programming Environment; Introduction; Hardware Configuration; Microprocessor - ZiLOG System 8000 User Manual

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USER
SECTION 2
PROGRAr.nUNG ENVIRONHENT
2.1 Introduction
The S8000 System uses a
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microprocessor-based operating
system to perform software development tasks. This section
provides the basis for all later discussions of Monitor Pro-
gram applications and I/O procedures.
The S8000 Monitor sets software breakpoints for program
debugging, and includes I/O control, interface software for
use with a serial interface to a remote computer system, and
the primary bootstrapper used to bring the system up.
2.2 Hardware Configuration
The following paragraphs briefly describe the major charac-
teristics of the S8000 hardware. Detailed general installa-
tion and maintenance information is contained in the S8000
Hardware Reference Manual. Figure 2-1 illustrates the func-
tional relationship of the S80nO hardware components.
2.2.1 Microprocessor
The architectural resources of the Z8000 CPU include sixteen
16-bit general-purpose registers, seven data types ranging
from 8-bit to 32-bit long words and byte strings, eight
user-selectable addressing modes, and 110 distinct instruc-
tion types. The CPU can address up to 16 megabytes in 128K
byte segments (64K bytes of data and 64K bytes of instruc-
tion). Moreover, more than 90% of the instructions can use
any of five main addressing modes, with 8-bit byte, 16-bit
word, and 32-bit long word data types.
The CPU has two operating modes, system and normal (user),
that keep operating system and applications programming
separate, as in computer systems. This separation of CPU
resources promotes the integrity of the system, since pro-
grams operating in normal mode cannot access those aspects
of the CPU that deal with time-dependent or system interface
events.
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