Computer Hardware User's Manual

Vol. 2A 3-161
INSTRUCTION SET REFERENCE, A-M
COMISS—Compare Scalar Ordered Single-Precision Floating-Point Values and Set EFLAGS
Virtual-8086 Mode Exceptions
Same exceptions as in real address mode.
#PF(fault-code) For a page fault.
#AC(0) If alignment checking is enabled and an unaligned memory
reference is made.
Compatibility Mode Exceptions
Same exceptions as in protected mode.
64-Bit Mode Exceptions
#SS(0) If a memory address referencing the SS segment is in a non-
canonical form.
#GP(0) If the memory address is in a non-canonical form.
#PF(fault-code) For a page fault.
#NM If CR0.TS[bit 3] = 1.
#XM If an unmasked SIMD floating-point exception and CR4.OSXM-
MEXCPT[bit 10] = 1.
#UD If an unmasked SIMD floating-point exception and CR4.OSXM-
MEXCPT[bit 10] = 0.
If CR0.EM[bit 2] = 1.
If CR4.OSFXSR[bit 9] = 0.
If CPUID.01H:EDX.SSE[bit 25] = 0.
If the LOCK prefix is used.
#AC(0) If alignment checking is enabled and an unaligned memory
reference is made while the current privilege level is 3.