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Re: [avr-chat] portable no-op with AVR GCC, AVR LIbc?
From: |
Weddington, Eric |
Subject: |
Re: [avr-chat] portable no-op with AVR GCC, AVR LIbc? |
Date: |
Sun, 29 Jan 2012 21:00:14 -0700 |
> -----Original Message-----
> From: address@hidden
[mailto:avr-chat-
> address@hidden On Behalf Of Anthony
Andriano
> Sent: Sunday, January 29, 2012 6:55 PM
> To: Britton Kerin
> Cc: address@hidden
> Subject: Re: [avr-chat] portable no-op with AVR GCC, AVR LIbc?
>
> There is also:
>
> __builtin_avr_delay_cycles(unsigned long __n);
This is the preferred method.
> The compiler will delay exactly as many cycles as you provide with the
> argument by inserting useless, and more importantly harmless, code. I
usually
> see something like a string of subtracts, adds, etc.
It should be "NOP" or "RJMP ." (which delays 2 cycles but just jumps to
the next instruction), and then typically loops formed around those
instructions to delay to the exact number of cycles.
Eric Weddington