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Intel 253666-024US User Manual

Page 395

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Vol. 2A 3-349

INSTRUCTION SET REFERENCE, A-M

FLDENV—Load x87 FPU Environment

FPU Flags Affected

The C0, C1, C2, C3 flags are loaded.

Floating-Point Exceptions

None; however, if an unmasked exception is loaded in the status word, it is generated
upon execution of the next “waiting” floating-point instruction.

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.

#NM

CR0.EM[bit 2] or CR0.TS[bit 3] = 1.

#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.

#UD

If the LOCK prefix is used.

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

CR0.EM[bit 2] or CR0.TS[bit 3] = 1.

#UD

If the LOCK prefix is used.

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

CR0.EM[bit 2] or CR0.TS[bit 3] = 1.

#PF(fault-code)

If a page fault occurs.

#AC(0)

If alignment checking is enabled and an unaligned memory

reference is made.

#UD

If the LOCK prefix is used.