On Jun 5, 2014, at 5:53 PM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > Il 02/06/2014 17:34, Nadav Amit ha scritto: >> In 64-bit mode, when the destination is a register, the assignment is done >> according to the operand size. Otherwise (memory operand or no 64-bit mode), a >> 16-bit assignment is performed. > > I'm sorry, I'm missing the place where 64-bit mode is taken into account? It is not, since on 32-bit mode the high-order 16 bits of a register destination are undefined. If I recall correctly, in this case the high-order 16-bits on native system actually reflect the high-order 16-bits of CR0. Therefore, regardless to the mode of operation: 1. If the target is memory - the destination is 16-bit 2. If the target is a register - the register is written according to the operand size. Nadav-- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html