CODEWITHSUNDEEP
hardwarecomputer-sciencelittle-man-computer
UnPatoCuacCuac
UnPatoCuacCuac

Reputation: 345

what must the minimum number of bits in each word of the Little Man computer be?

I came across the follow question while reading a CS book, can someone please explain it to me? >"The Little Man computer can have ten operation codes (0-9) and address 100 words of storage (0-99). If binary numbers are to replace decimal numbers, what must the minimum number of bits in each word of the LMC be?"

Upvotes: 0

Views: 1158

Answers (2)

Peter Higginson
Peter Higginson

Reputation: 1

The Little Man Computer is an architecture where one instruction is held in one word, therefore a word has to contain both the op code and the address. That means you have to hold 000 to 999 so my answer would be 10 bits. You could assume that the question implies the op code and address in separate fields - in that case you need 4 bits for the op code and 7 bits for the address making 11 in total.

Note that the LMC has a "jump if greater than or equal to zero" instruction and for this to mean anything you must be able to represent negative numbers - so that implies that memory has a sign bit. My own simulation allows -999 to +999 as numbers in memory.

Upvotes: 0

user1613254
user1613254

Reputation: 408

Since you need to be able to distinguish 10 codes for operation, the minimum word size would have to be 4 bits. Using 4 bits, you can represent up to 2^4 = 16 possible codes (since each bit can be 0 or 1). Anything less (2^3 = 8) will not allow a separate binary number for each code.

Upvotes: 1

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