Pioneer LD-V8000 User Manual page 21

2.4.1 Active Memory
The player's RAM is divided into seven 1022-byte blocks called Pages, and one
2-byte block called Register 0. Each RAM memory location is one eight-bit byte.
Memory locations begin at Address 0 and continue to Address 7155. Depending
upon the argument of the most recent Page (PAG) command, the active memory
may consist of one to seven pages, and Register 0. This gives an Active Memory
Size of 1024, 2046, ..., 7156 bytes. Register 0 is not changed by any program
load from disc and it occupies two fixed bytes of memory that are separate from all
of the pages. However, the two bytes of Register 0 can usually be addressed as the
last two program locations of Active Memory.
2.4.2 Program Area
The program area is a part or all of the player's Active Memory. Program
instructions (arguments and commands) are written into the program area, along
with other data (characters, etc.). A program is usually loaded from a videodisc in
units of one page, or, in unusual circumstances, as a partial page.
The size of the active program area can be set by the Page command, allowing
from 1 to 7 pages to be active. The actual size of the active program, including
Register 0, can be calculated as follows:
At power-on, there is only one page active (1022 bytes plus Register 0). This
provides for compatibility with earlier players and program dumps which do not
use the Page command. Beginners will often write program dumps for the
LD-V8000 in one of two ways:
• Without using the PAG command, for small programs or when
compatibility with the oldest players is desired.
• Using the "6 PAG" command to make the active memory as
large as possible.
Program instructions, (arguments and commands) are stored in coded format.
Each digit of an argument and each command is a one-byte code which occupies
one memory location. For example, the instruction, 1536 Search, consists of a
4-byte argument and the one-byte SC command, represented in memory by the
following five bytes of Hex code: 0F, AF, 4F, 6F, and F7.
See Chapter 4, Level II Commands the LD-V8000 for an explanation of specific
program commands and Appendix B, Alphabetical Listing of Level II
Commands Available on the LD-V8000. Both Chapter 4 and Appendix B
include the commands' corresponding one-byte Hex codes.
Pioneer LD-V8000 Level II User's Manual
Number of active pages x 1022 + 2 bytes
LD-V8000 Level II • Chapter Two
TP 114 v. 1.1 •
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