On Tue, Jan 11, 2011 at 7:22 PM, Ian Lance Taylor <i...@google.com> wrote: > Gidi Nave <gidi.nav...@gmail.com> writes: > >> On Tue, Jan 11, 2011 at 5:34 PM, Ian Lance Taylor <i...@google.com> wrote: >> >>> So why doesn't d1 = d1 + -96 match the last instruction there? >>> >> because it's: add d,d unsigned >> we don't have: add d,d signed >> >> and in this case we need: d = r + (-96) > > (Please don't top-post on this mailing list. Thanks.) > > Addition of signed and unsigned numbers is the same operation at the > machine level. Are there limitations on the signed value? If so, is > there is a sub instruction? > > Ian >
Hi Ian, There are limitation for the signed value for D class registers. There is a sub instruction for D registers, but it's limited to U5 (unsigned of 5 bits) which is not the case here. Thanks, Gidi.
