Section 1.3.1 #66

Hi,

The book says 'The writes into 32-bit parts, however, fill the upper 32 bits of the full register with sign bits. For example, zeroing eax will zero the entire rax, storing -1 into eax will fill the upper 32 bits with ones.'.

However Intel manual says in section 3.4.1.1:

32-bit operands generate a 32-bit result, zero-extended to a 64-bit result in the destination general-purpose register

I checked this in Visual Studio using a simple program:

.code
SomeFunction proc
	mov eax, -1
	ret
SomeFunction endp
end

The RAX register was zero extended as described in Intel manual.

Is this an error in the book?

Thanks and Regards
Dibyendu