Zilog Z8F0130 - Manual (Page 303)

UM013037-1212 Segments
Zilog Developer Studio II – Z8 Encore!
User Manual
279
Segments
Segments are used to represent regions of memory. Only one segment is considered active
at any time during the assembly process. A segment must be defined before setting it as
the current segment. Every segment is associated with one and only one address space.
The following sections describe segments:
•
Predefined Segments – see page 279
•
User-Defined Segments – see page 280
Predefined Segments
For convenience, the segments listed in the following table are predefined by the assem-
bler. Each segment gets assigned to one of the address spaces. All of the predefined seg-
ments listed here can be aligned on any byte boundary.
Initialized segments in RDATA or EDATA, such as NEAR_BSS or FAR_DATA, require
start-up code to initialize them because only segments in ROM or EROM can actually be
initialized by the assembler/linker. For an example of how to do this, study the C start-up
code, in
ZILOGINSTALL\ZDSII_product_version\src\rtl\common\ start-
ups.asm , and the linker command files automatically generated for a C project.
Table 52. Predefined Segments
Segment ID Space Contents Default Origin
near_bss RData Uninitialized data Relocatable
far_bss EData Uninitialized data Relocatable
near_data RData Initialized data Relocatable
far_data EData Initialized data Relocatable
rom_data ROM Initialized data Relocatable
near_txt RData String constants Relocatable
far_txt EData String constants Relocatable
rom_text ROM String constants Relocatable
code ROM Code Relocatable
text RData Initialized data Relocatable
__vectors_nnn ROM Interrupt vectors Absolute
pramseg PRAM Code Relocatable
Note: