| dbo:abstract |
In computer programming, an arithmetic shift is a shift operator, sometimes termed a signed shift (though it is not restricted to signed operands). The two basic types are the arithmetic left shift and the arithmetic right shift. For binary numbers it is a bitwise operation that shifts all of the bits of its operand; every bit in the operand is simply moved a given number of bit positions, and the vacant bit-positions are filled in. Instead of being filled with all 0s, as in logical shift, when shifting to the right, the leftmost bit (usually the sign bit in signed integer representations) is replicated to fill in all the vacant positions (this is a kind of sign extension). Some authors prefer the terms sticky right-shift and zero-fill right-shift for arithmetic and logical shifts respectively. Arithmetic shifts can be useful as efficient ways to perform multiplication or division of signed integers by powers of two. Shifting left by n bits on a signed or unsigned binary number has the effect of multiplying it by 2n. Shifting right by n bits on a two's complement signed binary number has the effect of dividing it by 2n, but it always rounds down (towards negative infinity). This is different from the way rounding is usually done in signed integer division (which rounds towards 0). This discrepancy has led to bugs in a number of compilers. For example, in the x86 instruction set, the SAR instruction (arithmetic right shift) divides a signed number by a power of two, rounding towards negative infinity. However, the IDIV instruction (signed divide) divides a signed number, rounding towards zero. So a SAR instruction cannot be substituted for an IDIV by power of two instruction nor vice versa. (en) 산술 시프트는 연산자 중 하나로서 특수한 2의 거듭제곱수(2, 4, 8, 16 ... 등)와 관련한 곱셈과 나눗셈을 연산할 때 사용된다.... (ko) Na programação de computadores, deslocamento aritmético é um operador de deslocamento que altera o numero binário, deslocando-o 'N' vezes, este podendo ser tanto feito para a esquerda como para a direita. Nestas condições, conclui-se que faz parte da lógica binária. (pt) 在程序设计中，算术移位是一种位操作，有时被称为有符号移位。它分為算术左移和算术右移。对于二进制数来说，算术移位可以移动每個數字的位置，即每個數字都能被移动，而空出的位置又被其他數字填充。当向右移动时，最左边的位置依舊保留原有位置的數值。 (zh) |
| rdfs:comment |
산술 시프트는 연산자 중 하나로서 특수한 2의 거듭제곱수(2, 4, 8, 16 ... 등)와 관련한 곱셈과 나눗셈을 연산할 때 사용된다.... (ko) Na programação de computadores, deslocamento aritmético é um operador de deslocamento que altera o numero binário, deslocando-o 'N' vezes, este podendo ser tanto feito para a esquerda como para a direita. Nestas condições, conclui-se que faz parte da lógica binária. (pt) 在程序设计中，算术移位是一种位操作，有时被称为有符号移位。它分為算术左移和算术右移。对于二进制数来说，算术移位可以移动每個數字的位置，即每個數字都能被移动，而空出的位置又被其他數字填充。当向右移动时，最左边的位置依舊保留原有位置的數值。 (zh) In computer programming, an arithmetic shift is a shift operator, sometimes termed a signed shift (though it is not restricted to signed operands). The two basic types are the arithmetic left shift and the arithmetic right shift. For binary numbers it is a bitwise operation that shifts all of the bits of its operand; every bit in the operand is simply moved a given number of bit positions, and the vacant bit-positions are filled in. Instead of being filled with all 0s, as in logical shift, when shifting to the right, the leftmost bit (usually the sign bit in signed integer representations) is replicated to fill in all the vacant positions (this is a kind of sign extension). (en) |
