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INSTRUCTION SET REFERENCE
IMUL—Signed Multiply (Continued)
Flags Affected
For the one operand form of the instruction, the CF and OF flags are set when significant bits
are carried into the upper half of the result and cleared when the result fits exactly in the lower
half of the result. For the two- and three-operand forms of the instruction, the CF and OF flags
are set when the result must be truncated to fit in the destination operand size and cleared when
the result fits exactly in the destination operand size. The SF, ZF, AF, and PF flags are undefined.
Protected Mode Exceptions
#GP(0)
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.
#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.
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.
#PF(fault-code)If a page fault occurs.
#AC(0)
If alignment checking is enabled and an unaligned memory reference is
made.
