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AIX Version 4.3 Assembler Language Reference

stmw or stm (Store Multiple Word) Instruction


Stores the contents of consecutive registers into a specified memory location.


stmw RS,D(RA)
stm RS,D(RA)


The stmw and stm instructions store N consecutive words from general-purpose register (GPR) RS through GPR 31. Storage starts at the effective address (EA). N is a register number equal to 32 minus RS.

If GPR RA is not 0, the EA is the sum of the contents of GPR RA and D. The sum is a 16-bit signed two's complement integer sign-extended to 32 bits. If GPR RA is 0, then the EA is D.

The stmw instruction has one syntax form. If the EA is not a multiple of 4, the results are boundedly undefined.

The stm instruction has one syntax form and does not affect the Fixed-Point Exception Register or Condition Register Field 0.


RS Specifies source general-purpose register of stored data.
D Specifies a 16-bit signed two's complement integer sign-extended to 32 bits for EA calculation.
RA Specifies source general-purpose register for EA calculation.


The following code stores the contents of GPR 29 through GPR 31 into a location in memory:

.csect data[rw]
buffer: .long 0,0,0
# Assume GPR 29 contains 0x1000 2200.
# Assume GPR 30 contains 0x1000 3300.
# Assume GPR 31 contains 0x1000 4400.
.csect text[pr]
stmw 29,buffer(4)
# Three consecutive words in storage beginning at the address
# of buffer are now 0x1000 2200 1000 3300 1000 4400.

Related Information

Fixed-Point Processor.

Fixed-Point Load and Store Instructions.

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