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SAR  -  Shift Right Instruction


The SAR instruction is used to perform an arithmetic shift right, resulting in a signed division.

As each bit is shifted, it passes in to the Carry flag, where it can be assessed using a conditional jump JC or JNC.

As each bit moves right the highest bit becomes zero.

This command has 3 part the Instruction, A Register or memory address, and the number of bits to shift right.


Assembly
Sample		 Description 16 bit Machine
Code
SAR AL, 1;  Shift AL right by 1 bit   D0 F8
SAR AL, CL;  Shift AL right by value of CL   D2 F8
SAR AL, 0x03 ;  Shift AL right by 8 bit immediate   C0 F8 03
SAR AX, 1;  Shift AL right by 1 bit   D1 F8
SAR AX, CL ;  Shift AL right by value of CL   D3 F8
SAR AX, 0x03 ;  Shift AL right by 8 bit immediate   C1 F8 03
SAR [BX], 1;  Shift memory address right by 1 bit   D1 3F
SAR [BX], CL;  Shift memory address right by value of CL   D3 3F
SAR [BX], 0x03 ;  Shift memory address right by 8 bit
;  immediate 		  C1 3F 03
SAR [BX+2], 1;  Shift memory address right by 1 bit   D1 7F 02
SAR [BX+2], CL ;  Shift memory address right by value of CL   D2 7F 02
SAR [BX+2], 0x03 ;  Shift memory address right by 8 bit
;  immediate 		  C1 7F 02 03