Intel 253668-032US User Manual

Page of 806
Vol. 3   6-41
INTERRUPT AND EXCEPTION HANDLING
Interrupt 9—Coprocessor Segment Overrun
Exception Class
Abort. (Intel reserved; do not use. Recent IA-32 processors 
do not generate this exception.)
Description
Indicates that an Intel386 CPU-based systems with an Intel 387 math coprocessor 
detected a page or segment violation while transferring the middle portion of an 
Intel 387 math coprocessor operand. The P6 family, Pentium, and Intel486 proces-
sors do not generate this exception; instead, this condition is detected with a general 
protection exception (#GP), interrupt 13.
Exception Error Code
None.
Saved Instruction Pointer
The saved contents of CS and EIP registers point to the instruction that generated the 
exception.
Program State Change
A program-state following
 a coprocessor segment-overrun ex
ception is unde-
fined. The program or task cannot be resumed or restarted. The only available action 
of the exception handler is to save the instruction pointer and reinitialize the x87 FPU 
using the FNINIT instruction.