ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Assembler syntax
STRD , , [, +/-] Offset: index==TRUE, wback==FALSE
STRD , , [, +/-]! Pre-indexed: index==TRUE, wback==TRUE
STRD , , [], +/- Post-indexed: index==FALSE, wback==TRUE
where:
See Standard assembler syntax fields on page A8-7.
The first source register. This register must be even-numbered and not R14.
The second source register. This register must be .
Instruction Details
The base register. The SP can be used. For offset addressing only, the PC can be used.
However, use of the PC is deprecated.
+/- Is + or omitted if the immediate offset is to be added to the base register value (add == TRUE),
or – if it is to be subtracted (add == FALSE).
Contains the offset that is added to the value of to form the address.
The pre-UAL syntax STRD is equivalent to STRD.
Operation
if ConditionPassed() then
EncodingSpecificOperations();
offset_addr = if add then (R[n] + R[m]) else (R[n] - R[m]);
address = if index then offset_addr else R[n];
MemA[address,4] = R[t];
MemA[address+4,4] = R[t2];
if wback then R[n] = offset_addr;
Exceptions
Data Abort.
ARM DDI 0406B Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. A8-399