shifters

Description

A demonstration of the RTLIB shift operators (hades.models.rtlib.arith.ShiftLeft, ShiftRightLogic, and ShiftRightArith). All components are set to 8-bit bus-width; the input and output components are set to binary display mode to make the bit-shifts explicit.

Unlike the bit-rotation operators, the shift-left operator fills the shifted word with zero-bits. The logic shift-right operator (SRL) also fills the shifted word with zero-bits, while the arithmetic shift-right operation copies the topmost (sign) bit of the original operand value. In two's complement encoding, this means that the output value of the arithmetic shift-right operation has the same sign as the input operand. The symbols used for the shift-operators use the Java notation, << for shift-left, >> for the standard arithmetic shift-right, and >>> for logic shift-right (unsigned).

Click the input switch (again, shift-click to decrement, control-click for U and Z) or type the 'a' bindkey to control the circuit.

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