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INSTRUCTION SET REFERENCE
FSTCW/FNSTCW—Store Control Word (Continued)
Protected Mode Exceptions
#GP(0)
If the destination is located in a nonwritable segment.
If a memory operand effective address is outside the CS, DS, ES, FS, or
GS segment limit.
If the DS, ES, FS, or GS register is used to access memory and it contains
a null segment selector.
#SS(0)
If a memory operand effective address is outside the SS segment limit.
#NM
EM or TS in CR0 is set.
#PF(fault-code)If a page fault occurs.
#AC(0)
If alignment checking is enabled and an unaligned memory reference is
made while the current privilege level is 3.
Real-Address Mode Exceptions
#GP
If a memory operand effective address is outside the CS, DS, ES, FS, or
GS segment limit.
#SS
If a memory operand effective address is outside the SS segment limit.
#NM
EM or TS in CR0 is set.
Virtual-8086 Mode Exceptions
#GP(0)
If a memory operand effective address is outside the CS, DS, ES, FS, or
GS segment limit.
#SS(0)
If a memory operand effective address is outside the SS segment limit.
#NM
EM or TS in CR0 is set.
#PF(fault-code)If a page fault occurs.
#AC(0)
If alignment checking is enabled and an unaligned memory reference is
made.
