Worst case memory access in 80x86 assembly -

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In an 80486 computer, the worst state of memory access to this instruction (Include Fitch) is: 

  Add [word] [x], 0x123FA4

It is known that with an operand one opcode has two bytes in length.

10 bytes I accept I am 484 freight 4 bytes memory with alliance with limitations of 4 byte DWORD in memory time. Therefore, 10 bytes sure reads 3 memory (= 10/4 is rounded) whether you keep them somewhere. Howevever, if the opcode byte is place in the last byte of a DWORD, the remaining 9 bytes can be actually 4 to the total number of readings of 3 more DWORDS periods.

To add, the position X should be obtained, assuming that X is divided into a DWORD limit -> 2 reads. Constantly adding is inside the CPU, and this amount is written while writing the same DWORD limit -> 2.

Therefore, the worst case scenario should be 8 memory operation.


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