Assembler Language Reference

stwux or stux (Store Word with Update Indexed) Instruction

Purpose

Stores a word of data from a general-purpose register into a specified location in memory and possibly places the address in another general-purpose register.

Syntax

Bits	Value
0-5	31
6-10	RS
11-15	RA
16-20	RB
212-30	183
31	/

PowerPC
stwux	RS, RA, RB

POWER family
stux	RS, RA, RB

Description

The stwux and stux instructions store the contents of general-purpose register (GPR) RS into the word of storage addressed by the effective address (EA).

If GPR RA is not 0, the EA is the sum of the contents of GPR RA and GPR RB. If GPR RA is 0, then the EA is the contents of GPR RB.

If GPR RA is not 0 and the storage access does not cause an Alignment Interrupt or a Data Storage Interrupt, then the EA is placed into GPR RA.

The stwux and stux instructions have one syntax form and do not affect the Fixed-Point Exception Register or Condition Register Field 0.

Parameters

RS	Specifies source general-purpose register of stored data.
RA	Specifies source general-purpose register for EA calculation and possible address update.
RB	Specifies source general-purpose register for EA calculation.

Examples

The following code stores the contents of GPR 6 into a location in memory:

.csect data[rw]
buffer: .long 0,0
# Assume GPR 4 contains 0x0000 0004.
# Assume GPR 23 contains the address of buffer.
# Assume GPR 6 contains 0x9000 3000.
.csect text[pr]
stwux 6,4,23
# buffer+4 now contains 0x9000 3000.
# GPR 4 now contains the address of buffer+4.

Related Information

Fixed-Point Processor .

Fixed-Point Load and Store with Update Instructions .