Re: [avr-chat] effects of ATOMIC_FORCEON and NONATMOIC_FORCEOFF

[Michael Hennebry]

On Sat, 11 Apr 2015, Britton Kerin wrote:

> The documentation for ATOMIC_FORCEON contains this:
>
>     This is a possible parameter for ATOMIC_BLOCK. When used, it will cause
>     the ATOMIC_BLOCK to force the state of the   SREG register on exit,
>     enabling the Global Interrupt Status flag bit. This saves on flash
>     space as the previous value of the SREG register does not need to be
>     saved at the start of the block.
>
> The documentation for NONATOMIC_FORCEOFF contains somehting similar.
>
> I thin in both these cases, in addition to saved flash space there is going
> to be a little bit of RAM space and possible few instructions, correct?

The savings are normally 1 word of flash, 1 cycle and 1 register.
If there is register pressure, the savings could be larger.

--
Michael   address@hidden
"SCSI is NOT magic. There are *fundamental technical
reasons* why it is necessary to sacrifice a young
goat to your SCSI chain now and then."   --   John Woods