A
ATran
Guest
I have an unsigned 8-bit comparator in verilog, How would I change it
to become a signed 8-bit comparator?
to become a signed 8-bit comparator?
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N
Neo
Guest
st0p@hotmail.com (ATran) wrote in message news:<425982b8.0411212030.29fb1a19@posting.google.com>...
if both are positive select the comparator output,
if both are negetive invert the comparator ouput,
if they are different and a is +ve then select comparator output.
if they are different and b is +ve then select not of comparator output.
well you can use the two sign bits and make 2 to 1 mux withI have an unsigned 8-bit comparator in verilog, How would I change it
to become a signed 8-bit comparator?
if eqn is (a>b)?
if both are positive select the comparator output,
if both are negetive invert the comparator ouput,
if they are different and a is +ve then select comparator output.
if they are different and b is +ve then select not of comparator output.
G
glen herrmannsfeldt
Guest
Neo wrote:
Anyway, invert the sign bits and do an unsigned compare.
If this is homework, reference the newsgroup as a source.
Did you know that the 8080 and Z80 don't have signed compare
instructions?
-- glen
Shouldn't it be the positive one is greater if the signs are different?st0p@hotmail.com (ATran) wrote in message news:<425982b8.0411212030.29fb1a19@posting.google.com>...
I have an unsigned 8-bit comparator in verilog, How would I change it
to become a signed 8-bit comparator?
if eqn is (a>b)?
well you can use the two sign bits and make 2 to 1 mux with
if both are positive select the comparator output,
if both are negetive invert the comparator ouput,
if they are different and a is +ve then select comparator output.
if they are different and b is +ve then select not of comparator output.
Anyway, invert the sign bits and do an unsigned compare.
If this is homework, reference the newsgroup as a source.
Did you know that the 8080 and Z80 don't have signed compare
instructions?
-- glen
S
Steven Sharp
Guest
glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in message news:<co2j30$is3$1@gnus01.u.washington.edu>...
of operand a in as the MSB of operand b, and vice versa.
Or I think you could save the inverters by feeding the sign bitAnyway, invert the sign bits and do an unsigned compare.
of operand a in as the MSB of operand b, and vice versa.
G
glen herrmannsfeldt
Guest
Steven Sharp wrote:
though exchanging bits shouldn't be too slow.
In software, exchanging sign bits is expensive, but, yes,
in non-FPGA logic you could exchange them. There might be
some routing cost, but it should be small.
-- glen
In FPGA designs, inverters are free in just about every case,glen herrmannsfeldt <gah@ugcs.caltech.edu> wrote in message news:<co2j30$is3$1@gnus01.u.washington.edu>...
Anyway, invert the sign bits and do an unsigned compare.
Or I think you could save the inverters by feeding the sign bit
of operand a in as the MSB of operand b, and vice versa.
though exchanging bits shouldn't be too slow.
In software, exchanging sign bits is expensive, but, yes,
in non-FPGA logic you could exchange them. There might be
some routing cost, but it should be small.
-- glen