Section 20.13.7 of the Xmega manual speaks about the requirement of 16 bit
alignment.
http://www.atmel.com/images/doc8331.pdf
As the MAXIMUM_ALIGNMENT in avr.h is set to 1, it throws an error when trying
to compile.
I have attached a patch which sets it to 2 by default in the compiler.
I have also attached a case which fails.
Would this be an acceptable change ?
-George-
struct testStruct {
char a;
int b;
float c;
};
/*volatile struct testStruct testObj; */
char a __attribute__ ((aligned (2)));
int main () {
a = 2;
/*
testObj.a = 'c';
testObj.b = 6;
return testObj.a;
*/
}
diff -Naurp gcc/config/avr/avr.h gcc/config/avr/avr.h
--- gcc/config/avr/avr.h 2012-11-16 13:43:25.000000000 +0530
+++ gcc/config/avr/avr.h 2012-11-16 14:12:32.000000000 +0530
@@ -245,8 +245,8 @@ enum
#define EMPTY_FIELD_BOUNDARY 8
-/* No data type wants to be aligned rounder than this. */
-#define BIGGEST_ALIGNMENT 8
+/* For Xmega USB buffers */
+#define BIGGEST_ALIGNMENT 16
#define TARGET_VTABLE_ENTRY_ALIGN 8
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