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ST9 USER GUIDE

5.4.1.10 INCDIR = ...

This variable must contain the list of directories that contains header files needed by the pro-

gram. Example:

INCDIR = ..\INCLUDE ..\HEADER

5.4.1.11 Make Rules

A Make rule is a statement that both tells which file is dependent on which other file, and the

processing needed in order to update the result file when the source file has changed.

All files written under MS-DOS are marked in the directory with a date/time stamp. This allows

the Make utility to compare dates between files. If a file declared in a rule as being the result

of a source file, and the source file has a later date than that of the result, the result must be

regenerated. For example, in the following rule:

%.o:%.c

$(GCC) $(CFLAGS) $< -o $@

The first line says that any file with extension .c is the source for the corresponding .o file, so

that if the .c file is younger than the .o file, the source file must be recompiled.

The second line says that the compilation is done using GCC9, with the options stored in the

CFLAGS variable, that the input file "$<" is the .c file (source file), and the output file "$@",

specified by option -o, is the target file.

5.4.2 Writing the Linker Command File using a Script File

The linker uses the linker command file(7)(or Script File) to correctly position the code and vari-

ables in the memory spaces. It defines the start and end of the ROM and RAM area(s), and

gives the list of the object files to be linked. It also generates the appropriate labels to allow C

variables to receive their initial values before the program starts.

Once the Script File is written, the only thing you have to do is to add new file names or change

the mapping.

Below is an example of a generic script file for an ST92F150:

MEMORY

{

FLASH0

: ORIGIN = 0x000000, LENGTH = 8K

FLASH1

: ORIGIN = 0x002000, LENGTH = 8K

FLASH2

: ORIGIN = 0x004000, LENGTH = 48K

FLASH3

: ORIGIN = 0x010000, LENGTH = 64K, MMU = IDPR0 IDPR1

(7) ST9 Family GNU Software tools, Second Part: LD9.

ST9 Datasheet(PDF) 119 Page - STMicroelectronics