Zilog EZ80F916 - Manual (Page 203)

UM014423-0607
ZiLOG Developer Studio II
eZ80Acclaim! ® User Manual
183
Address spaces and segments are described in the following sections:
•
“Allocating Processor Memory” on page 183
•
“Address Spaces” on page 183
•
“Segments” on page 184
•
“Assigning Memory at Link Time” on page 186
Allocating Processor Memory
All memory locations, whether data or code, must be defined within a segment. There are
two types of segments:
•
Absolute segments
An absolute segment is any segment with a fixed origin. The origin of a segment is
defined with the ORG directive. All data and code in an absolute segment are located
at the specified physical memory address.
•
Relocatable segments
A relocatable segment is a segment without a specified origin. At link time, linker
commands are used to specify where relocatable segments are to be located within
their space. Relocatable segments can be assigned to different physical memory
locations without re-assembling.
Address Spaces
The memory regions for the eZ80Acclaim! microprocessor are represented by the address
spaces listed in the following table.
Table 7. eZ80Acclaim! Address Spaces
Space ID
Display
Prefix
Description
Lowest and
Highest
Addresses
Size
Maximum That
Can Be Retrieved
at One Time
ROM C Standard memory address space.
The ROM memory address space
can contain both program code
and data. If no address space is
associated with a segment, this is
the default space.
00000000-
00FFFFFF
16 MB 3 bytes
(24 bits)
RAM D Random access memory address
space. The RAM memory address
space can contain variable data
and stack.
00000000-
00FFFFFF
16 MB 3 bytes
(24 bits)