What is shr in x86?
Description. The shr or sar instruction is used to shift the bits of the operand destination to the right, by the number of bits specified in the count operand. Bits shifted beyond the destination are first shifted into the CF flag.
What is shr in assembly?
The SHR (shift right) instruction performs a logical right shift on the destination operand. The highest bit position is filled with a zero.
What is difference between SAR and shr?
sar rounds toward negative infinity; the high-order bit remains unchanged. shr right shifts (unsigned divides) a byte, word, or long value for a count specified by an immediate value and stores the quotient in that byte, word, or long respectively.
What are the five categories of the x86 instructions?
Contents
- 1 x86 integer instructions. 1.1 Original 8086/8088 instructions.
- 2 x87 floating-point instructions. 2.1 Original 8087 instructions.
- 3 SIMD instructions. 3.1 MMX instructions.
- 4 Cryptographic instructions. 4.1 Intel AES instructions.
- 5 Virtualization instructions.
- 6 Undocumented instructions.
- 7 See also.
- 8 References.
What does JLE do in assembly?
The jle instruction is a conditional jump that follows a test. It performs a signed comparison jump after a cmp if the destination operand is less than or equal to the source operand.
How does CDQ work?
The CDQ instruction copies the sign (bit 31) of the value in the EAX register into every bit position in the EDX register. The CWD instruction is intended for use when the operand-size attribute is 16 and the CDQ instruction for when the operand-size attribute is 32.
What is RCR in assembly language?
Rotate With Carry Right (rcr)
What are the instruction of SHR and SAR in 8086?
SHR : Shift Right. SAR : Shift Arithmetic Right. SHL : Shift Left.
What does cmp do in x86?
The CMP instruction compares two operands. It is generally used in conditional execution. This instruction basically subtracts one operand from the other for comparing whether the operands are equal or not. It does not disturb the destination or source operands.
What is Shr instruction in C++?
The shr or sar instruction is used to shift the bits of the operand destination to the right, by the number of bits specified in the count operand. Bits shifted beyond the destination are first shifted into the CF flag. Equivalent to dividing by 2 3 This could be written as follows in python:
What is the SAR instruction in Intel® 64?
In effect, the SAR instruction fills the empty bit position’s shifted value with the sign of the unshifted value (see Figure 7-9 in the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 1 ). The SAR and SHR instructions can be used to perform signed or unsigned division, respectively, of the destination operand by powers of 2.
What is the size of the of flag in SHR instruction?
For the SHR instruction, the OF flag is set to the most-significant bit of the original operand. In 64-bit mode, the instruction’s default operation size is 32 bits and the mask width for CL is 5 bits. Using a REX prefix in the form of REX.R permits access to additional registers (R8-R15).
What is the difference between SHR and SAR in Python?
This could be written as follows in python: shr fills with zeroes, and sar fills with the sign bit.