Additional keywords for storage specification – Zilog ZUSBOPTS User Manual
Page 185
UM017105-0511
Language Extensions
Zilog Developer Studio II – ZNEO™
User Manual
157
The enumeration data type is defined as
int
as per ANSI C. The C-Compiler provides
language extension to specify the enumeration data type to be other than
int
.
•
Setting Flash Option Bytes in C
The ZNEO CPU has four Flash option bytes. The C-Compiler provides language
extension to define these Flash option bytes.
•
Supported New Features from the 1999 Standard
The ZNEO C-Compiler is based on the 1989 ANSI C standard. Some new features
from the 1999 standard are supported in this compiler for ease of use.
Additional Keywords for Storage Specification
The
_Near
,
_Far
,
_Rom
, and
_Erom
keywords are storage class specifiers and are used to
control the allocation of data objects by the compiler. They can be used on individual data
objects similar to
const
and
volatile
keywords in the ANSI C standard. The storage
specifiers can only be used to control the allocation of global and static data. The alloca-
tion of local data (nonstatic local) and function parameters is decided by the compiler and
is described in later sections. Any storage specifier used on local and parameter data is
ignored by the compiler.
The Zilog header file <
zneo.h
> defines macros to permit the use of the more familiar
keywords:
near
,
far
,
rom
, and
erom
. The reason for not using these keywords directly is
to avoid conflict with C identifiers in a preexisting C program. (To avoid conflicts, current
ANSI recommendations are that keywords for vendor extensions to the C language begin
with an underscore and capital letter.)
The data allocation for various storage class specifiers is shown in Figure 126 and
described in the following sections:
•
•
•
•