Zilog ZUSBOPTS - Manual (Page 352)

Program Configurations UM017105-0511
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Zilog Developer Studio II – ZNEO™
User Manual
C Program Setup
The C program setup for Copy to RAM Program Configuration is similar to the Default
Program Configuration with some additional steps as described in this section.
The C-Compiler by default generates the executable program code under one unified seg-
ment named CODE. The CODE segment belongs to the EROM address space.
1. To set up this configuration, you must place the CODE segment in RAM at run time
and EROM at load time. Do this by adding the following linker commands in the
Additional Linker Directives dialog box (see Additional Directives – see page 62):
change code=RAM /* Run time CODE is in RAM space */
copy code EROM /* Load time CODE is in EROM space */
define _low_code_copy = copy base of CODE
define _low_code = base of CODE
define _len_code = length of CODE
2. The linker COPY directive only designates the load addresses and the run-time
addresses for the segment. The actual copying of the segment must be performed by
the start-up code. For example, if you are using the small model, copy and modify the
C startup provided in the installation under
src\boot\common\startupexs.asm ,
rewriting the relevant section as follows:
;
; Copy CODE into RAM
;
LEA R0,_low_code_copy
LEA R1,_low_code
LD R2,#_len_code+1
JP clab1
clab0:
LD.B R3,(R0++)
LD.B (R1++),R3
clab1:
DJNZ R2,clab0
XREF _low_code_copy:EROM
XREF _len_code
XREF _low_code:RAM
3. Finally, add your modified start-up module to your project by selecting the Included
in Project button in the Objects and Libraries page of the Project Settings dialog
box (see C Start-up Module – see page 66) and also add the modified source code file
to your project using the Add Files command from the Project menu.