VHSUB

Vector Halving Subtract subtracts the elements of the second operand from the corresponding elements of the first operand, shifts each result right one bit, and places the final results in the destination vector. The results of the halving operations are truncated. There is no rounding version.

The operand and result elements are all the same type, and can be any one of:

• 8-bit, 16-bit, or 32-bit signed integers.
• 8-bit, 16-bit, or 32-bit unsigned integers.

Depending on settings in the CPACR, NSACR, and HCPTR registers, and the Security state and PE mode in which the instruction is executed, an attempt to execute the instruction might be undefined, or trapped to Hyp mode. For more information see Enabling Advanced SIMD and floating-point support.

It has encodings from the following instruction sets: A32 ( A1 ) and T32 ( T1 ) .

A1

if Q == '1' && (Vd<0> == '1' || Vn<0> == '1' || Vm<0> == '1') then UNDEFINED; if size == '11' then UNDEFINED; add = (op == '0'); unsigned = (U == '1'); esize = 8 << UInt(size); elements = 64 DIV esize; d = UInt(D:Vd); n = UInt(N:Vn); m = UInt(M:Vm); regs = if Q == '0' then 1 else 2;

T1

if Q == '1' && (Vd<0> == '1' || Vn<0> == '1' || Vm<0> == '1') then UNDEFINED; if size == '11' then UNDEFINED; add = (op == '0'); unsigned = (U == '1'); esize = 8 << UInt(size); elements = 64 DIV esize; d = UInt(D:Vd); n = UInt(N:Vn); m = UInt(M:Vm); regs = if Q == '0' then 1 else 2;