about struct pointer for CortexMx

Enhance struct pointer access, by placing scalars at the beginning and arrays as sub-sequent struct members.

Thumb2 instructions encode a limited displacement for memory
access. When a struct is accessed via a pointer, scalar variables
at the beginning of a struct can be directly accessed. Arrays
always require address calculations. Therefore, it is more efficient to
place scalar variables at the beginning of a struct

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Frankly speaking, I don't understand above form uvision4 tutorial. English is not my native language.

anybody can help explain its details? why scalar variables
at the beginning of a struct will bring more efficiency? Thank you very much.

typedef struct { int x; int arr[10]; } sx;
int f (sx xdata *sp, int i) {
return sp->arr[i];
}

BR,