in this program user will enter a number 0 to 9. and without Mul, Div , Neg, Not I have to find these one : where n is integer

Bx = 2^n

Cx= bx/4

Dx = 1's compliment of Bx


I am a beginner, i want some help. Please just give me just hint to solve my problem.

Sorry, can't do it for you! But your teacher most likely told you how and you missed the boat!

Let's do these things backwards from simplest to most complex!

You're teacher must have taught you that a 1's complement is the inversion (flipping) of the bits.

0A5h
1010 0101         0A5h (165 unsigned, -165 signed)
0101 1010         05Ah (90)

2's complement is used for a subtraction operation. 1's complement then add 1

0101 1011          05Bh (91)

So

 0111 1011         07Bh (123)
 0001 0111         17h  (23)    {subtract}
 1110 1000         E8h      1's complemenet 17h         
 1110 1001         E9h      2's complement
     now sum
  0111 1011        7Bh (123)
  1110 1001        E9h       {ADD}
--------------
   0110 0100     64h (  100)

WOW! MAGIC!!!!

Okay next problem.
Processors typically have two kinds of shifts though some have four such as the 80x86.

Shift Logical Left
Shift Arithmetic Left
Are the same thing.

01011010     5Ah (90)
10110100     B4h (180)

The bits get shifted left by N bits. In that case it was by 1 bit. This is effectively a multiply!

Logical Shift Right

1010 0101             A5 (165)
0101 0010  -> 1     52 (82)

In a Logical Shift Right a zero bit was clocked into the high bit!

For an Arithmetic Shift Right the MSB (Most Significant Bit) the sign bit, acts like a sticky bit. It stays in place and then shifts the data down.

1010 0101       A5 (165 unsigned     -91 signed))
1101 0010   ->1   D2 (210 unsigned   -46 signed)

So shift left once is a divide by 2. Shift left twice is a divide by 4.

They cheated here and made this number a base 2.

2^1 = 2
2^2 = 4
2^3 = 8

Left shift????

Also 2^3 = 2*2*2 three 2's.
5^3 = 5*5*5 = 125

Left Shift & Right Shift
Left Rotate & Right Rotate


This post has been edited by wildgoose: 31 Oct, 2009 - 10:21 AM