Aes256

Reinhard

Because my daily work with crypto stuff, today I found this C code

http://www.literatecode.com/aes256

compiled without any modifications under propgcc .... and run successfull !

Dave Hein

Very nice!

Reinhard

Well, this can open many doors for the chip.

Btw. in this code I see quite often the modifier register. Use the compiler really a cogregister for the variable or is this more a proposal ?

Heater.

R
"register" is only a suggestion to the compiler that the variable can be placed in a register for some optimization. The compiler need not actually do that. For example if the target machine is stack based with no registers.
If you can get the "register" vars to live in cog all the better.

Dave Hein

PropGCC uses 16 cog registers. As Heater said, the register keyword is a suggestion to the compiler to keep the variable in a register. You can run "propeller-elf-gcc -S file.c" to generate the file.s assembly file. You can look at the assembly file to see if the compiler kept the variable in a register. The optimizer does a good job of keeping variables in registers even without using the register keyword.