C++ Source-Level Optimizations

25112 Rev. 3.06 September 2005

FIXED_U_16_16 z;

z.whole = x.whole + y.whole; return(z);

}

__inline unsigned int fixed_int(FIXED_U_16_16 x) { return (x.whole >> 16);

}

...

FIXED_U_16_16 y, z; unsigned int q;

...

label1:

y= fixed_add (y, z); q = fixed_int (y);

label2:

...

The object code generated for the source code between label1 and label2 typically looks like this:

mov edx, DWORD PTR [z]
mov eax, DWORD PTR [y]
add eax, edx
mov DWORD PTR [y], eax	; -+
mov eax, DWORD PTR [y]	; <+ Aligned (size/address match)--forwarding in LSU
shr eax, 16
mov DWORD PTR [q], eax

C and C++ Source-Level Optimizations

Chapter 2