ALXD800EEXJ2VD AMD (ADVANCED MICRO DEVICES), ALXD800EEXJ2VD Datasheet - Page 614

• Manufacturer Part Number: ALXD800EEXJ2VD
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of ALXD800EEXJ2VD

• Operating Temperature (min): 0C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

8.1.1
Prefix bytes can be placed in front of any instruction to modify the operation of that instruction. When more than one prefix
is used, the order is not important. There are five types of prefixes that can be used:
1)
2)
3)
4)
Table 8-3 lists the encoding for different types of prefix bytes.
614
Field Name
Prefix (optional)
Opcode
mod
reg
r/m
ss
index
base
Address Displacement
Immediate Data
Prefix
ES:
CS:
SS:
DS:
FS:
GS:
Operand Size
Address Size
LOCK
REPNE
REP/REPE
Segment Override explicitly specifies which segment register the instruction will use for effective address calculation.
Address Size switches between 16-bit and 32-bit addressing by selecting the non-default address size.
Operand Size switches between 16-bit and 32-bit operand size by selecting the non-default operand size.
Repeat is used with a string instruction to cause the instruction to be repeated for each element of the string.
Prefix (Optional)
Encoding
33234C
2Eh
3Eh
26h
36h
64h
65h
66h
67h
F0h
F2h
F3h
Description
Prefix Field(s): One or more optional fields that are used to specify segment register over-
ride, address and operand size, repeat elements in string instruction, and LOCK# assertion.
Opcode Field: Identifies instruction operation.
Address Mode Specifier: Used with the r/m field to select addressing mode.
General Register Specifier: Uses reg, sreg3, or sreg2 encoding depending on opcode field.
Address Mode Specifier: Used with mod field to select addressing mode.
Scale factor: Determines scaled-index address mode.
Index: Determines general register to be used as index register.
Base: Determines general register to be used as base register.
Displacement: Determines address displacement.
Immediate Data: Immediate data operand used by instruction.
Description
Override segment default, use ES for memory operand.
Override segment default, use CS for memory operand.
Override segment default, use SS for memory operand.
Override segment default, use DS for memory operand.
Override segment default, use FS for memory operand.
Override segment default, use GS for memory operand.
Make operand size attribute the inverse of the default.
Make address size attribute the inverse of the default.
Assert LOCK# internal hardware signal.
Repeat the following string instruction.
Repeat the following string instruction.
Table 8-3. Instruction Prefix Summary
Table 8-2. Instruction Fields
AMD Geode™ LX Processors Data Book
Instruction Set