how to use register as global variable

Franz Kurniawan

hi..

i'm using LCDK C6748 dev tools..

i need to write a code which required a very fast processing (up to 12 machine cycles only)

this code is within interrupt routine , and the interrupt routine will be called every 12 clocks..

therefore i want to use register as global variable to avoid memory access which require high machine cycles..

is there a way to preserve a register ? so that i can access these registers anywhere within the code, especially from interrupt routine

0 Titusrathinaraj Stalin over 11 years ago

Hi Franz,

In my understanding,

The "register" variable can't be used as a "global"

For speedup, you can go for optimization.

0 Franz Kurniawan over 11 years ago in reply to Titusrathinaraj Stalin

hi titus,

thanks for your respond..

i already read that document and found that mostly the pipelining works for looping..

in my case, the code will be executed repeatedly via interrupt (PWMEventISR) every TBPRD count..

and the most consuming machine cycles are the LDW and STW command into global variables..

so i was thinking about replacing this global variables (save in memory) into register..

therefore instead of using LDW and STW, i can directly do arithmetic operation into it over and over again..

by this way , it is possible to save much more machine cycle..

am i understanding correct? please correct me if im wrong..

or is it a way to reserve / protect the compiler to use some register? therefore i can use that register as "global variable"

0 Titusrathinaraj Stalin over 11 years ago in reply to Franz Kurniawan

I moved your post to compiler forum and you would get exact answer from there.

0 Archaeologist over 11 years ago

I'm sorry, the C6000 compiler does not support reserving a register as a global register.

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