VCVTN (floating-point)

Convert floating-point to integer with Round to Nearest converts a value in a register from floating-point to a 32-bit integer using the Round to Nearest rounding mode, and places the result in a second register.

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.

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

A1

313029282726252423222120191817161514131211109876543210
111111101D111101Vd10!= 00op1M0Vm
RMsize

Encoding for the Half-precision scalar variant
(FEAT_FP16)

Applies when (size == 01)

VCVTN{<q>}.<dt>.F16 <Sd>, <Sm>

Encoding for the Single-precision scalar variant

Applies when (size == 10)

VCVTN{<q>}.<dt>.F32 <Sd>, <Sm>

Encoding for the Double-precision scalar variant

Applies when (size == 11)

VCVTN{<q>}.<dt>.F64 <Sd>, <Dm>

Decode for all variants of this encoding

if size == '00' || (size == '01' && !IsFeatureImplemented(FEAT_FP16)) then UNDEFINED; constant rounding = FPDecodeRM(RM); constant unsigned = (op == '0'); constant d = UInt(Vd:D); constant integer esize = 8 << UInt(size); constant integer m = if size == '11' then UInt(M:Vm) else UInt(Vm:M);

T1

15141312111098765432101514131211109876543210
111111101D111101Vd10!= 00op1M0Vm
RMsize

Encoding for the Half-precision scalar variant
(FEAT_FP16)

Applies when (size == 01)

VCVTN{<q>}.<dt>.F16 <Sd>, <Sm>

Encoding for the Single-precision scalar variant

Applies when (size == 10)

VCVTN{<q>}.<dt>.F32 <Sd>, <Sm>

Encoding for the Double-precision scalar variant

Applies when (size == 11)

VCVTN{<q>}.<dt>.F64 <Sd>, <Dm>

Decode for all variants of this encoding

if InITBlock() then UNPREDICTABLE; if size == '00' || (size == '01' && !IsFeatureImplemented(FEAT_FP16)) then UNDEFINED; constant rounding = FPDecodeRM(RM); constant unsigned = (op == '0'); constant d = UInt(Vd:D); constant integer esize = 8 << UInt(size); constant integer m = if size == '11' then UInt(M:Vm) else UInt(Vm:M);

CONSTRAINED UNPREDICTABLE behavior

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

Assembler Symbols

<q>

See Standard assembler syntax fields.

<dt>

Is the data type for the elements of the destination, encoded in op:

op <dt>
0 U32
1 S32
<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.

<Dm>

Is the 64-bit name of the SIMD&FP source register, encoded in the "M:Vm" field.

Operation

EncodingSpecificOperations(); CheckVFPEnabled(TRUE); constant FPCR_Type fpcr = EffectiveFPCR(); case esize of when 16 S[d] = FPToFixed(H[m], 0, unsigned, fpcr, rounding, 32); when 32 S[d] = FPToFixed(S[m], 0, unsigned, fpcr, rounding, 32); when 64 S[d] = FPToFixed(D[m], 0, unsigned, fpcr, rounding, 32);


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

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