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(Registers/Counters) - What is the final contents of the register?

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kuranme

New Member
The contents of a 8-bit register is initially 01110111. The register is shifted right six times with the serial input being 011001. The same register is then shifted left 4 times with the serial input being 0101. What is the final contents of the register?
 

Pommie

Well-Known Member
Most Helpful Member
Serial means that you give 1 bit to the register per 1 clock cycle (1 shift).
I know what serial means or rather, I assumed that's what it meant. However the answer is dependant on if it's MSB or LSB first. There is also a third possibility - the bits are shifted the same way as the register. So, three possible answers due to an incomplete question.

Mike.
 

NsrMagazin

Member
Normally there is only 1 input, you can not shift with 2 inputs unless the register is designed for it.

If there is 1 input:
Shifting to the left clears the LSB bits being shifted and shifts the rest to the left.

If you want to shift with 2 inputs, that means that you have to supply the bits from the other end in which case the result is clear. However this requirement is not mentioned and ambiguous.
 

Pommie

Well-Known Member
Most Helpful Member
Ahah, we finally agree. It's an ambiguous question. As a computer programmer since the 70s I should be able to answer these type of questions but teachers keep asking incomplete questions.

Mike.
 
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