3-13
INSTRUCTION SET REFERENCE
NOTES:
1. The UD2 instruction was introduced in the Pentium
®
Pro processor.
2. This exception was introduced in the Intel486 processor.
3. This exception was introduced in the Pentium
®
processor and enhanced in the Pentium
®
A
Pro processor.
4. This exception was introduced in the Pentium
®
III processor.
3.1.8.Virtual-8086 Mode Exceptions
The Virtual-8086 Mode Exceptions section lists the exceptions that can occur when the
instruction is executed in virtual-8086 mode.
Table 3-2. Exception Mnemonics, Names, and Vector Numbers
Vector
No.Mnemonic
Name
Source
0
#DEDivide Error
DIV and IDIV instructions.
1
#DBDebug
Any code or data reference.
3
#BPBreakpoint
INT 3 instruction.
4
#OFOverflow
INTO instruction.
5
#BRBOUND Range Exceeded
BOUND instruction.
6
#UDInvalid Opcode (Undefined
Opcode)
UD2 instruction or reserved opcode.
1
7
#NMDevice Not Available (No Math
Coprocessor)
Floating-point or WAIT/FWAIT
instruction.
8
#DFDouble Fault
Any instruction that can generate an
exception, an NMI, or an INTR.
10
#TSInvalid TSS
Task switch or TSS access.
11
#NPSegment Not Present
Loading segment registers or accessing
system segments.
12
#SSStack Segment Fault
Stack operations and SS register loads.
13
#GPGeneral Protection
Any memory reference and other
protection checks.
14
#PFPage Fault
Any memory reference.
16
#MFFloating-Point Error (Math Fault)Floating-point or WAIT/FWAIT
instruction.
17
#ACAlignment Check
Any data reference in memory.
2
18
#MCMachine Check
Model dependent.
3
19
#XFSIMD Floating-Point Numeric
Error
Streaming SIMD Extensions
4
