Texas Instruments TMS320C54x, User Manual

Page: 240 / 469

The MEMORY Directive
7-28
When you use the MEMORY directive, be sure to identify all the memory
ranges that are available for object code. Memory defined by the MEMORY
directive is
configured memory; any memory that you do not explicitly account
for with the MEMORY directive is unconfigured memory. The linker does not
place any part of a program into unconfigured memory. You can represent non-
existent memory spaces by simply not including an address range in a
MEMORY directive statement.
The MEMORY directive is specified in a command file by the word MEMORY
(uppercase), followed by a list of memory range specifications enclosed in
braces. The MEMORY directive in Example 7–3 defines a system that has 4K
words of ROM at address C00h in program memory, 32 words of RAM at
address 60h in data memory, and 4K words at address 80h in data memory.
Example 7–3. The MEMORY Directive
/**************************************************/
/* Sample command file with MEMORY directive */
/**************************************************/
file1.obj file2.obj /* Input files */
–o prog.out /* Options */
MEMORY
{
PAGE 0:
ROM: origin = C00h, length = 1000h
PAGE 1: SCRATCH: origin = 60h, length = 20h
ONCHIP: origin = 80h, length = 1000h
}
origins lengths
MEMORY
directive
PAGE
options
names