.TH "<avr/cpufunc.h>: Special AVR CPU functions" 3avr "Wed Jun 4 2014" "Version 1.8.0svn" "avr-libc" \" -*- nroff -*-
.ad l
.nh
.SH NAME
<avr/cpufunc.h>: Special AVR CPU functions \- 
.SS "Macros"

.in +1c
.ti -1c
.RI "#define \fB_NOP\fP()"
.br
.ti -1c
.RI "#define \fB_MemoryBarrier\fP()"
.br
.in -1c
.SH "Detailed Description"
.PP 

.PP
.nf
#include <avr/cpufunc\&.h> 

.fi
.PP
.PP
This header file contains macros that access special functions of the AVR CPU which do not fit into any of the other header files\&. 
.SH "Macro Definition Documentation"
.PP 
.SS "#define _MemoryBarrier()"
Implement a read/write \fImemory barrier\fP\&. A memory barrier instructs the compiler to not cache any memory data in registers beyond the barrier\&. This can sometimes be more effective than blocking certain optimizations by declaring some object with a \fCvolatile\fP qualifier\&.
.PP
See \fBProblems with reordering code\fP for things to be taken into account with respect to compiler optimizations\&. 
.SS "#define _NOP()"
Execute a \fIno operation\fP (NOP) CPU instruction\&. This should not be used to implement delays, better use the functions from <\fButil/delay_basic\&.h\fP> or <\fButil/delay\&.h\fP> for this\&. For debugging purposes, a NOP can be useful to have an instruction that is guaranteed to be not optimized away by the compiler, so it can always become a breakpoint in the debugger\&. 
.SH "Author"
.PP 
Generated automatically by Doxygen for avr-libc from the source code\&.