The difference becomes important when dealing with negative numbers.) (1u << 2)-1 gives 0x3, a mask of ones 2 bits wide. -8 >> 2 arithmetic shift gives 0xFFFFFFFE. Answer. Two zeroes getting shifted out, two ones shifted in. If v is signed, a right shift is arithmetic and the sign bit is shifted in from the left (sign-extension) Rotate. If v is unsigned, a right shift is logical. 4. According to IEEE1800-2012 >> is a binary logical shift, while >>> is a binary arithmetic shift.. Basically, arithmetic shift uses context to determine the fill bits, so: arithmetic right shift (>>>) - shift right specified number of bits, fill with value of sign bit if expression is signed, otherwise fill with zero,arithmetic left shift (<<<) - shift left specified number of bits, fill with zero. Two zeroes getting shifted out, two zeroes shifted in. (1u << 2) gives 0x4. For example, −3 shifted right two bits yields −1. Circular shifts. When I place a 2's compliment number into the array and arithmetically shift the number, it logical shifts instead: registers[0][0] = 16'b1000000000000000; registers[0][0] = registers[0][0]>>>2; Apparently, the system will logical shift instead of arithmetically shift if the number is not signed. Arithmetic shift means that the replaced bits are substituted in order to maintain the sign of the original number. An arithmetic shift right by two bits gives 1111 1111 1111 1011, which is −5. 2. So arithmetic shifts round toward −∞.) Shift the mask 0x3 in place, 32-2=30 bits to the left. An "arithmetic" shift leaves the original value in the leftmost bit. 4. 09/10/2018 Comp 411 - Fall 2017 ... Arithmetic right Shifts behave like dividing the contents of a register by 2s where s is the shift amount, if you assume the contents of the register are signed. Shift Type 00 - logical left 01 - logical right 10 - arithmetic right 11 - rotate right. In left logical shift 0’s are replaced by discarded bits. ... 2 Answers 2 I think..... arithmetic right shift will shift in the sign bit while preserving the sign bit .. What are logical operations. For example, assuming a … v<> operator in C is a logical shift. Difference between arithmetic and logical shift. How can AND operation be used as a mask. Similarly, −20 is 1111 1111 1110 1100. Efficient way to perform multiplication (shifting left n bits) and division (shift right n bits) of signed integers using power of 2. The corresponding logical shift would be 0x3FFFFFFE. When shifting a signed value, the >> operator is an arithmetic shift. Note that the following constructions are compiled to a single rotate instruction: Shift functions are found in numeric_std package file; Shift functions can perform both logical (zero-fill) and arithmetic (keep sign) shifts; Type of shift depends on input to function. If the first operand is of type uint or ulong, the right-shift is a logical shift.