Zilog Z8F0130 - Manual (Page 268)

Using the ANSI C-Compiler UM013037-1212
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Zilog Developer Studio II – Z8 Encore!
User Manual
Customizing Start-Up Files
The C start-up object files provided with the Z8 Encore! C Compiler are generic files and
can be tailored to meet the application requirements. Before modifying the C start-up
module, perform the following steps:
1. Copy the corresponding C start-up source file to a new file in your project directory.
For the small model, use startups.asm as the file from which you copy; for the
large model, use startupl.asm .
2. Add the newly copied C start-up file to your project files by using the Add Files com-
mand from the Project menu.
3. Select the Settings command from the Project menu.
The Project Settings dialog box is displayed.
4. Select the Objects and Libraries page.
5. Select the Included in Project and Use Standard Start-Up Linker Commands
checkboxes.
Use the following guidelines when customizing the C start-up file:
•
If you do not have any uninitialized global or static variables in near memory, the
start-up file does not have to clear the near uninitialized variables to zero.
As an example, for the large model:
near int val; // Not OK to skip clearing uninitialized near
data:

// Uninitialized global in near memory

int val ; // OK to skip clearing uninitialized near data:

// Uninitialized global in far memory
For the small model:
int val; // Not OK to skip clearing uninitialized near data:

// Uninitialized global in near memory

far int val ; // OK to skip clearing uninitialized near data:

// Uninitialized global in far memory
Alternatively, if your application does not assume that the near uninitialized global or
static variables are initialized to zero by the C start-up module, the start-up code does
not have to perform this function.
This can be achieved by adding the following code just before segment startup :
CLRRRAM SET FALSE
•
If you do not have any initialized global or static variables in near memory, the start-
up code does not have to set the initialized global and static near variables to their ini-
tial value from ROM.
As an example, for the large model: