Reserved Opcodes

Table A–2 Architecture Instructions (Continued)

Mnemonic

Format

Opcode

Description

 

 

 

 

STW

Mem

0D

Store word

SUBF

F-P

15.081

Subtract F_floating

SUBG

F-P

15.0A1

Subtract G_floating

SUBL

Opr

10.09

Subtract longword

SUBL/V

Opr

10.49

Subtract longword with integer overflow enable

SUBQ

Opr

10.29

Subtract quadword

SUBQ/V

Opr

10.69

Subtract quadword with integer overflow enable

SUBS

F-P

16.081

Subtract S_floating

SUBT

F-P

16.0A1

Subtract T_floating

TRAPB

Mfc

18.0000

Trap barrier

UMULH

Opr

13.30

Unsigned multiply quadword high

UNPKBL

Opr

1C.35

Unpack bytes to longwords

UNPKBW

Opr

1C.34

Unpack bytes to words

WH64

Mfc

18.F800

Write hint — 64 bytes

WMB

Mfc

18.4400

Write memory barrier

XOR

Opr

11.40

Logical difference

ZAP

Opr

12.30

Zero bytes

ZAPNOT

Opr

12.31

Zero bytes not

 

 

 

 

A.2 Reserved Opcodes

This section describes the opcodes that are reserved in the Alpha architecture. They can be reserved for Compaq or for PALcode.

A.2.1 Opcodes Reserved for Compaq

Table A–3lists opcodes reserved for Compaq.

Table A–3 Opcodes Reserved for Compaq

Mnemonic

Opcode

Mnemonic

Opcode

 

 

 

 

OPC01

01

OPC05

05

OPC02

02

OPC06

06

OPC03

03

OPC07

07

OPC04

04

 

 

 

 

A–8Alpha Instruction Set

Alpha 21264/EV67 Hardware Reference Manual

Page 274
Image 274
Compaq EV67, 21264 specifications Reserved Opcodes, Opcodes Reserved for Compaq