Difficulty understanding Configuration Register Bits

binaryhat

I'm reading chapter 5 of Lammle's book and I do not see how the bits are on in relation to bit number.

For example, 0x2102 means bits 13, 8 and 1 are on. I don't understand how that is determined. I understand hexadecimal notation and nibble (4 bits).

See attached imaged.

SteveO86

0010 0001 0000 0010

0010 = 2
0001 = 1
0000 = 0
0010 = 2

Total = 2102

Numerical values correlate as below:

Numerical Value               8 4 2 1
Place where bit is tuned on:  0 0 0 0

It's the same concept with an IP Address in Binary. I would look over Binary to Decimal conversations.

Then the Config register has it's own value.

Hope this helps.

MosGuy

Break it up and calculate each individual number:

8 4 2 1

---

2= 0010
1= 0001
0= 0000
2= 0010

= 0010000100000010

Looks like SteveO86 beat me to it

binaryhat

So for 0x2142 (password recovery) it would be:

0010 = 2
0001 = 1
0100 = 4
0010 = 2

Bit #: 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Binary: 0 0 1 0 0 0 0 1 0 1 0 0 0 0 1 0

2142

I see it now. Every 4 bits is a nibble, 8 4 2 1.

Thanks!