VSELEQ, VSELGE, VSELGT, VSELVS

Floating-point conditional select allows the destination register to take the value in either one or the other source register according to the condition codes in the APSR.

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

A1

313029282726252423222120191817161514131211109876543210
111111100DccVnVd10!= 00N0M0Vm
size

Encoding for the Equal, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 00 && size == 01)

VSELEQ.F16 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Equal, single-precision scalar variant

Applies when (cc == 00 && size == 10)

VSELEQ.F32 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Equal, double-precision scalar variant

Applies when (cc == 00 && size == 11)

VSELEQ.F64 <Dd>, <Dn>, <Dm> // (Cannot be conditional)

Encoding for the Greater than or Equal, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 10 && size == 01)

VSELGE.F16 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Greater than or Equal, single-precision scalar variant

Applies when (cc == 10 && size == 10)

VSELGE.F32 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Greater than or Equal, double-precision scalar variant

Applies when (cc == 10 && size == 11)

VSELGE.F64 <Dd>, <Dn>, <Dm> // (Cannot be conditional)

Encoding for the Greater than, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 11 && size == 01)

VSELGT.F16 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Greater than, single-precision scalar variant

Applies when (cc == 11 && size == 10)

VSELGT.F32 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Greater than, double-precision scalar variant

Applies when (cc == 11 && size == 11)

VSELGT.F64 <Dd>, <Dn>, <Dm> // (Cannot be conditional)

Encoding for the Unordered, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 01 && size == 01)

VSELVS.F16 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Unordered, single-precision scalar variant

Applies when (cc == 01 && size == 10)

VSELVS.F32 <Sd>, <Sn>, <Sm> // (Cannot be conditional)

Encoding for the Unordered, double-precision scalar variant

Applies when (cc == 01 && size == 11)

VSELVS.F64 <Dd>, <Dn>, <Dm> // (Cannot be conditional)

Decode for all variants of this encoding

if size == '00' || (size == '01' && !IsFeatureImplemented(FEAT_FP16)) then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer d = if size == '11' then UInt(D:Vd) else UInt(Vd:D); constant integer n = if size == '11' then UInt(N:Vn) else UInt(Vn:N); constant integer m = if size == '11' then UInt(M:Vm) else UInt(Vm:M); constant bits(4) condition = cc:(cc<1> EOR cc<0>):'0';

T1

15141312111098765432101514131211109876543210
111111100DccVnVd10!= 00N0M0Vm
size

Encoding for the Equal, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 00 && size == 01)

VSELEQ.F16 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Equal, single-precision scalar variant

Applies when (cc == 00 && size == 10)

VSELEQ.F32 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Equal, double-precision scalar variant

Applies when (cc == 00 && size == 11)

VSELEQ.F64 <Dd>, <Dn>, <Dm> // (Not permitted in IT block)

Encoding for the Greater than or Equal, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 10 && size == 01)

VSELGE.F16 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Greater than or Equal, single-precision scalar variant

Applies when (cc == 10 && size == 10)

VSELGE.F32 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Greater than or Equal, double-precision scalar variant

Applies when (cc == 10 && size == 11)

VSELGE.F64 <Dd>, <Dn>, <Dm> // (Not permitted in IT block)

Encoding for the Greater than, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 11 && size == 01)

VSELGT.F16 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Greater than, single-precision scalar variant

Applies when (cc == 11 && size == 10)

VSELGT.F32 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Greater than, double-precision scalar variant

Applies when (cc == 11 && size == 11)

VSELGT.F64 <Dd>, <Dn>, <Dm> // (Not permitted in IT block)

Encoding for the Unordered, half-precision scalar variant
(FEAT_FP16)

Applies when (cc == 01 && size == 01)

VSELVS.F16 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Unordered, single-precision scalar variant

Applies when (cc == 01 && size == 10)

VSELVS.F32 <Sd>, <Sn>, <Sm> // (Not permitted in IT block)

Encoding for the Unordered, double-precision scalar variant

Applies when (cc == 01 && size == 11)

VSELVS.F64 <Dd>, <Dn>, <Dm> // (Not permitted in IT block)

Decode for all variants of this encoding

if InITBlock() then UNPREDICTABLE; if size == '00' || (size == '01' && !IsFeatureImplemented(FEAT_FP16)) then UNDEFINED; constant integer esize = 8 << UInt(size); constant integer d = if size == '11' then UInt(D:Vd) else UInt(Vd:D); constant integer n = if size == '11' then UInt(N:Vn) else UInt(Vn:N); constant integer m = if size == '11' then UInt(M:Vm) else UInt(Vm:M); constant bits(4) condition = cc:(cc<1> EOR cc<0>):'0';

CONSTRAINED UNPREDICTABLE behavior

If InITBlock(), then one of the following behaviors must occur:

Assembler Symbols

<Dd>

Is the 64-bit name of the SIMD&FP destination register, encoded in the "D:Vd" field.

<Dn>

Is the 64-bit name of the first SIMD&FP source register, encoded in the "N:Vn" field.

<Dm>

Is the 64-bit name of the second 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.

<Sn>

Is the 32-bit name of the first SIMD&FP source register, encoded in the "Vn:N" field.

<Sm>

Is the 32-bit name of the second SIMD&FP source register, encoded in the "Vm:M" field.

Operation

EncodingSpecificOperations(); CheckVFPEnabled(TRUE); case esize of when 16 H[d] = if ConditionHolds(condition) then H[n] else H[m]; when 32 S[d] = if ConditionHolds(condition) then S[n] else S[m]; when 64 D[d] = if ConditionHolds(condition) then D[n] else D[m];


Internal version only: isa v01_32, pseudocode v2024-12_rel ; Build timestamp: 2024-12-16T10:54

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