New/Altered Exceptions
Exception 9 Is Now Reserved
In pre-486 processors, this was the Coprocessor Segment Overrun exception. It was changed to Reserved starting with the 486 (and is still reserved).
In the pre-486 processors, this exception indicated that a 386 system with a 387 coprocessor detected a page or segment violation while transferring the middle portion of a math coprocessor operand. Starting with the 486, processors do not generate this exception; instead, this condition is reported with a General Protection (GP) exception 13. A more detailed description of this exception can be found in “Coprocessor Segment Overrun Exception (9)” on page 304.
Exception 17 (Alignment Check) Added
This exception was Reserved prior to the 486.
The ...
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