Re: confused with 1's and 2's complements systems - From:
"robin" <robin51@xxxxxxxxxxxxxxxxxx> - Date: Fri, 7 Jan 2011
14:10:38 +1100 "Mark" <mark_cruzNOTFORSPAM@xxxxxxxxxxx> wrote in
message news:ig10t6$s9s$1@xxxxxxxxxxxxxxxxxxxx | I was reading a
wiki's article about representation of negative number by |
computers and by the end of the article got completely confused.
| I understand that one's or two's complement systems are used
*exclusively* | for negative numbers representation, i.e. | if x
< 0, then ~x + 1 produces two's complement value. | (As I
understood the 1's complement systems are rare now, and mainly |
What I can't understand is: | 1) is this operation performed by
CPU's ALU block ? | 2) when exactly, at what stage is this
operation taking place by a CPU? | 3) what value is stored in
registers -- two's complemented or not? | 4) the article says
that the most significant bit is a sign bit, but bitwise | NOT
will negate this bit and we loose the knowledge if the number's
Consider the following de