Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

   ◄Key to Timings►  ◄EA Calculation►  ◄Back►  ◄Contents►
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  Components               EA Clocks      Example
  Displacement                  6         mov   ax,stuff
  Base or index                 5         mov   ax,[bx]
  Displacement                  9         mov   ax,[bp+8]
  BP+DI or BX+SI                7         mov   ax,[bx+si]
  BP+SI or BX+DI                8         mov   ax,[bx+di]
  BP+DI+disp or BX+SI+disp     11         mov   ax,stuff[bx+si]
  BP+SI+disp or BX+DI+disp     12         mov   ax,stuff[bx+di]
  Segment override           EA+2         mov   ax,es:stuff
 
  On the 80286 and 80386, do not add Effective Address calculation time,
  unless base, index, and displacement are all used, in which case add
  1 clock.
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