VABS
Vector Absolute
Vector Absolute takes the absolute value of each element in a vector, and places the results in a second vector. The floating-point version only clears the sign bit.
Depending on settings in the CPACR, NSACR, HCPTR, and FPEXC 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.
If CPSR.DIT is 1 and this instruction passes its condition execution check and is operating only on integer vector elements, then the following apply:
The execution time of this instruction is independent of:The values of the data supplied in any of its registers.The values of the NZCV flags.
The response of this instruction to asynchronous exceptions does not vary based on:The values of the data supplied in any of its registers.The values of the NZCV flags.
It has encodings from the following instruction sets:
A32 (
A1
and
A2
)
and
T32 (
T1
and
T2
)
.
1
1
1
1
0
0
1
1
1
1
1
0
1
0
1
1
0
0
0
VABS{<c>}{<q>}.<dt> <Dd>, <Dm>
1
VABS{<c>}{<q>}.<dt> <Qd>, <Qm>
if size == '11' then UNDEFINED;
if F == '1' && ((size == '01' && !HaveFP16Ext()) || size == '00') then UNDEFINED;
if Q == '1' && (Vd<0> == '1' || Vm<0> == '1') then UNDEFINED;
advsimd = TRUE; floating_point = (F == '1');
esize = 8 << UInt(size); elements = 64 DIV esize;
d = UInt(D:Vd); m = UInt(M:Vm); regs = if Q == '0' then 1 else 2;
!= 1111
1
1
1
0
1
1
1
0
0
0
0
1
0
1
1
0
0
1
VABS{<c>}{<q>}.F16 <Sd>, <Sm>
1
0
VABS{<c>}{<q>}.F32 <Sd>, <Sm>
1
1
VABS{<c>}{<q>}.F64 <Dd>, <Dm>
if FPSCR.Len != '000' || FPSCR.Stride != '00' then UNDEFINED;
if size == '00' || (size == '01' && !HaveFP16Ext()) then UNDEFINED;
if size == '01' && cond != '1110' then UNPREDICTABLE;
advsimd = FALSE;
integer esize;
integer d;
integer m;
case size of
when '01' esize = 16; d = UInt(Vd:D); m = UInt(Vm:M);
when '10' esize = 32; d = UInt(Vd:D); m = UInt(Vm:M);
when '11' esize = 64; d = UInt(D:Vd); m = UInt(M:Vm);
size == '01' && cond != '1110'
The instruction executes as if it passes the Condition code check.
The instruction executes as NOP. This means it behaves as if it fails the Condition code check.
1
1
1
1
1
1
1
1
1
1
1
0
1
0
1
1
0
0
0
VABS{<c>}{<q>}.<dt> <Dd>, <Dm>
1
VABS{<c>}{<q>}.<dt> <Qd>, <Qm>
if size == '11' then UNDEFINED;
if F == '1' && ((size == '01' && !HaveFP16Ext()) || size == '00') then UNDEFINED;
if F == '1' && size == '01' && InITBlock() then UNPREDICTABLE;
if Q == '1' && (Vd<0> == '1' || Vm<0> == '1') then UNDEFINED;
advsimd = TRUE; floating_point = (F == '1');
esize = 8 << UInt(size); elements = 64 DIV esize;
d = UInt(D:Vd); m = UInt(M:Vm); regs = if Q == '0' then 1 else 2;
F == '1' && size == '01' && InITBlock()
The instruction executes as if it passes the Condition code check.
The instruction executes as NOP. This means it behaves as if it fails the Condition code check.
1
1
1
0
1
1
1
0
1
1
1
0
0
0
0
1
0
1
1
0
0
1
VABS{<c>}{<q>}.F16 <Sd>, <Sm>
1
0
VABS{<c>}{<q>}.F32 <Sd>, <Sm>
1
1
VABS{<c>}{<q>}.F64 <Dd>, <Dm>
if FPSCR.Len != '000' || FPSCR.Stride != '00' then UNDEFINED;
if size == '00' || (size == '01' && !HaveFP16Ext()) then UNDEFINED;
if size == '01' && InITBlock() then UNPREDICTABLE;
advsimd = FALSE;
integer esize;
integer d;
integer m;
case size of
when '01' esize = 16; d = UInt(Vd:D); m = UInt(Vm:M);
when '10' esize = 32; d = UInt(Vd:D); m = UInt(Vm:M);
when '11' esize = 64; d = UInt(D:Vd); m = UInt(M:Vm);
size == '01' && InITBlock()
The instruction executes as if it passes the Condition code check.
The instruction executes as NOP. This means it behaves as if it fails the Condition code check.
<c>
For encoding A1: see Standard assembler syntax fields. This encoding must be unconditional.
<c>
For encoding A2, T1 and T2: see Standard assembler syntax fields.
<q>
See Standard assembler syntax fields.
<dt>
Is the data type for the elements of the vectors,
F
size
<dt>
0
00
S8
0
01
S16
0
10
S32
1
01
F16
1
10
F32
<Qd>
Is the 128-bit name of the SIMD&FP destination register, encoded in the "D:Vd" field as <Qd>*2.
<Qm>
Is the 128-bit name of the SIMD&FP source register, encoded in the "M:Vm" field as <Qm>*2.
<Dd>
Is the 64-bit name of the SIMD&FP destination register, encoded in the "D:Vd" field.
<Dm>
Is the 64-bit name of the SIMD&FP source register, encoded in the "M:Vm" field.
<Sd>
Is the 32-bit name of the SIMD&FP destination register, encoded in the "Vd:D" field.
<Sm>
Is the 32-bit name of the SIMD&FP source register, encoded in the "Vm:M" field.
if ConditionPassed() then
EncodingSpecificOperations(); CheckAdvSIMDOrVFPEnabled(TRUE, advsimd);
if advsimd then // Advanced SIMD instruction
for r = 0 to regs-1
for e = 0 to elements-1
if floating_point then
Elem[D[d+r],e,esize] = FPAbs(Elem[D[m+r],e,esize]);
else
result = Abs(SInt(Elem[D[m+r],e,esize]));
Elem[D[d+r],e,esize] = result<esize-1:0>;
else // VFP instruction
case esize of
when 16 S[d] = Zeros(16) : FPAbs(S[m]<15:0>);
when 32 S[d] = FPAbs(S[m]);
when 64 D[d] = FPAbs(D[m]);