Implementation Specific (implspec.py)

This page contains information about the Utility Functions needed to operate the CPU such as generating bits, inverting bits, bit and reading bits.

Utility Functions

These functions exist due to the implementation in Python and to make testing the functions and methods easier. The logic remains the same without these functions.

Push to Tuple

Push to tuple takes in an n sized array of binary values and creates a tuple of binary values Tuple-binary.

implspec.pushToTuple(array, bits)

Parameters:

array ([]) – Preinitialised array of size n.
bits (int) – Binary number of size n.

Returns:

Tuple-Binary of type tuple.

Tip

The bits are reversed to make trailing zeros important For example: 1,0,0,... is 4 (in binary) but will not be recognised because when pushed to the tuple it will be (...,0,0,1). To fix this the bits are reversed. For example: 1,0,1,... which means 3 (in binary). When reversed and pushed to a tuple it will be (1,0,1,...) preserving the meaning of the binary.

Hint

Tuple-binary values are always in reverse binary order, where the leftmost bit is the least significant and vice-versa.

Generate X Bits

Generator function exists to make writing tests and inputs easier. Without this function I would have to ‘cheat’ in a sense and use string subscripting with integer conversion.

There are 4, 8 and 16 bit generators.

They take in a one n-bit binary number (where n < specified-bit).

Returns a tuple-binary of size n.

generate8Bits(0b10)
Output: (0,1,0,0,0,0,0,0)

generate16Bits(0b10)
Output: (0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0)

Generate Stream Bits

Due to the implementation of the Generate X Bits, the 16-bit variant of Switches needs to be of size 16.

Where the function does this:

if bit == 1:
    return 0b1111111111111111
else:
    return 0b0000000000000000

Call the function generateStreamBits and provide one 1-bit value.

generateStreamBits(1)
Output: 65535 # decimal representation

Tuple to Binary

Tuple-to-binary takes in a tuple-binary of size n and produces a value of size n in an integer representation (it will be of type int in Python).

The argument supplied is the tuple-binary.

The return value is an integer.

tupleToBinary((1,0))
Output: 2 # decimal representation

Less Than Zero

In order to determine if a number is negative (less than zero) the 16th bit is read. If it’s 1 then the number is negative.

The argument supplied is the tuple-binary.

The return value is an integer, 1 if its true, zero if false.

isLessThanZero((1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0))
Output: 1

isLessThanZero((0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1))
Output: 0