In message 20041031080457.27425.qmail@web12009.mail.yahoo.com you wrote:
I want to make gzipped hello_world application and later execute it using bootm command.
Please use correct terms. The "hello_world" is so small that compressing it makes no sense. Maybe you are talking about some other standalone application, which is bigger?
I figured that mkimage is the utility for making compressed STANDALONE image.
But it needs an option mkimage -d <datafile>
Now what is this datafile? Is it hello_world or hello_world.bin or hello_world.srec
It is none of them. You mentioned that you want to build a compressed image, so you must compress the fiule first, and none of hello_world nor hello_world.bin nor hello_world.srec is compressed. Also, ask yoruself if the processor will be able to find executable instructions in a S-Record file, or in a ELF header. it will not.
You should run gzip on hello_world.bin and use the resulting compressed binary image as input.
I tried all 3, but they give different sizes of gzipped image. So i am confused.
I would be confused if it was different. Since mkimage always adds a 64 byte header, the resulting file sizes MUST be different when you use files with different sizes as input.
Best regards,
Wolfgang Denk