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

Instruction Details
A8.6.302 VDUP (scalar)
Vector Duplicate duplicates a scalar into every element of the destination vector.
The scalar, and the destination vector elements, can be any one of 8-bit, 16-bit, or 32-bit bitfields. There is
no distinction between data types.
For more information about scalars see Advanced SIMD scalars on page A7-9.
Encoding T1 / A1 Advanced SIMD
VDUP. ,
VDUP. ,
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 1 1 1 1 1 1 1 D 1 1 imm4 Vd 1 1 0 0 0 Q M 0 Vm
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 1 1 0 0 1 1 1 D 1 1 imm4 Vd 1 1 0 0 0 Q M 0 Vm
if imm4 == ‘x000’ then UNDEFINED;
if Q == ‘1’ && Vd == ‘1’ then UNDEFINED;
case imm4 of
when ‘xxx1’ esize = 8; elements = 8; index = UInt(imm4);
when ‘xx10’ esize = 16; elements = 4; index = UInt(imm4);
when ‘x100’ esize = 32; elements = 2; index = UInt(imm4);
d = UInt(D:Vd); regs = if U == ‘0’ then 1 else 2;
A8-592 Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. ARM DDI 0406B