Category:8086 Assembly: Difference between revisions

 

While both the 8086 and the 8087 can read the same code, data, and memory, they cannot read the contents of each other's registers. So for example, if you wanted to use the 8087 to perform a calculation and then output the result to the screen, you'd need to give the 8087 the command to do the math and store the result into RAM. Then, the 8086 would read that RAM and output the result to the screen. The 8087 also doesn't have the robust indexed addressing modes of the 8086 - so the 8086 will often do the job of looking up a value from a table, then dumping that value into a temporary "loading zone" at a known location where the 8087 can more easily read from. In order to make sure that the 8086 and 8087 stay in sync, the 8086 can <code>WAIT</code> for the 8087 to finish its current instruction before executing more instructions. This is incredibly useful in the event that the 8086 needs to use a calculation that the 8087 did - it might end up reading from the "loading zone" before the 8087 actually has put the result of the calculation in it! (Most assemblers will handle this for you.)

 

===Looping Constructs===