Zilog Z8F0130 - Manual (Page 126)

Using the Integrated Development Environment UM013037-1212
102
Zilog Developer Studio II – Z8 Encore!
User Manual
Standard Library adapted for embedded applications, as described more fully in the Using
the ANSI C-Compiler section on page 193. If your project makes any calls to standard
library functions, you must select the C Runtime Library checkbox unless you prefer to
provide your own code for all library functions that you call. As noted in the Additional
Object/Library Modules section on page 99, you can also set up your application to call a
mixture of Zilog-provided functions and your own customized library functions. To do so,
select the
C Runtime Library checkbox. Calls to standard library functions will then call
the functions in the Zilog default library except when your own customized versions exist.
Zilog’s version of the C run-time library is organized with a separate module for each
function or, in a few cases, for a few closely related functions. Therefore, the linker links
only those functions that you actually call in your code. This means that there is no unnec-
essary code size penalty when you select the
C Runtime Library checkbox; only functions
you call in your application are linked into your application.
Floating Point Library
The Floating Point Library drop-down list box allows you to choose which version of the
subset of the C run-time library that deals with the floating-point operations will be linked
to your application:
Real. If you select Real , the true floating-point functions are linked in, and you can per-
form any floating-point operations you want in your code.
Dummy . If you select Dummy , your application is linked with alternate versions that are
stubbed out and do not actually carry out any floating-point operations. This dummy float-
ing-point library has been developed to reduce code bloat caused by including calls to
printf() and related functions such as sprintf() . Those functions in turn make calls
to floating-point functions for help with formatting floating-point expressions, but those
calls are unnecessary unless you actually must format floating-point values. For most
users, this problem has now been resolved by the
Generate Printfs Inline checkbox (see
the Generate Printfs Inline section on page 84 for a full discussion). You only need to
select the dummy floating-point library if you have to disable the Generate Printfs Inline
checkbox and your application uses no floating-point operations. In that case, selecting
Dummy keeps your code size from bloating unnecessarily.
None. If you select None , no floating-point functions are linked to your application at all.
This can be a way of ensuring that your code does not inadvertently make any floating-
point calls, because, if it does and this option is selected, you receive an error or warning
message about an undefined symbol.
Zilog Standard Library (Peripheral Support)
Select this checkbox to use the Zilog Standard Library (ZSL) in addition to the run-time
library (described in the
Using the ANSI C-Compiler chapter on page 193). The ZSL con-
tains functions for controlling the UART device driver and GPIO ports.