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

Assembler syntax
USADA8 , , ,
where:
See Standard assembler syntax fields on page A8-7.
The destination register.
The first operand register.
The second operand register.
The register that contains the accumulation value.
Operation
if ConditionPassed() then
EncodingSpecificOperations();
absdiff1 = Abs(UInt(R[n]) - UInt(R[m]));
absdiff2 = Abs(UInt(R[n]) - UInt(R[m]));
absdiff3 = Abs(UInt(R[n]) - UInt(R[m]));
absdiff4 = Abs(UInt(R[n]) - UInt(R[m]));
result = UInt(R[a]) + absdiff1 + absdiff2 + absdiff3 + absdiff4;
R[d] = result;
Exceptions
None.
Instruction Details
ARM DDI 0406B Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. A8-503