UCVTF (vector, integer)

Unsigned integer Convert to Floating-point (vector). This instruction converts each element in a vector from an unsigned integer value to a floating-point value using the rounding mode that is specified by the FPCR, and writes the result to the SIMD&FP destination register.

A floating-point exception can be generated by this instruction. Depending on the settings in FPCR, the exception results in either a flag being set in FPSR, or a synchronous exception being generated. For more information, see Floating-point exception traps.

Depending on the settings in the CPACR_EL1, CPTR_EL2, and CPTR_EL3 registers, and the Security state and Exception level in which the instruction is executed, an attempt to execute the instruction might be trapped.

It has encodings from 4 classes: Scalar half precision , Scalar single-precision and double-precision , Vector half precision and Vector single-precision and double-precision

Scalar half precision
(FEAT_FP16)

313029282726252423222120191817161514131211109876543210
0111111001111001110110RnRd
Uaopcode

UCVTF <Hd>, <Hn>

if !IsFeatureImplemented(FEAT_FP16) then UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); constant integer esize = 16; constant integer datasize = esize; integer elements = 1; boolean unsigned = (U == '1');

Scalar single-precision and double-precision

313029282726252423222120191817161514131211109876543210
011111100sz100001110110RnRd
Uopcode

UCVTF <V><d>, <V><n>

integer d = UInt(Rd); integer n = UInt(Rn); constant integer esize = 32 << UInt(sz); constant integer datasize = esize; integer elements = 1; boolean unsigned = (U == '1');

Vector half precision
(FEAT_FP16)

313029282726252423222120191817161514131211109876543210
0Q10111001111001110110RnRd
Uaopcode

UCVTF <Vd>.<T>, <Vn>.<T>

if !IsFeatureImplemented(FEAT_FP16) then UNDEFINED; integer d = UInt(Rd); integer n = UInt(Rn); constant integer esize = 16; constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize; boolean unsigned = (U == '1');

Vector single-precision and double-precision

313029282726252423222120191817161514131211109876543210
0Q1011100sz100001110110RnRd
Uopcode

UCVTF <Vd>.<T>, <Vn>.<T>

integer d = UInt(Rd); integer n = UInt(Rn); if sz:Q == '10' then UNDEFINED; constant integer esize = 32 << UInt(sz); constant integer datasize = 64 << UInt(Q); integer elements = datasize DIV esize; boolean unsigned = (U == '1');

Assembler Symbols

<Hd>

Is the 16-bit name of the SIMD&FP destination register, encoded in the "Rd" field.

<Hn>

Is the 16-bit name of the SIMD&FP source register, encoded in the "Rn" field.

<V>

Is a width specifier, encoded in sz:

sz <V>
0 S
1 D
<d>

Is the number of the SIMD&FP destination register, encoded in the "Rd" field.

<n>

Is the number of the SIMD&FP source register, encoded in the "Rn" field.

<Vd>

Is the name of the SIMD&FP destination register, encoded in the "Rd" field.

<T>

For the half-precision variant: is an arrangement specifier, encoded in Q:

Q <T>
0 4H
1 8H

For the single-precision and double-precision variant: is an arrangement specifier, encoded in sz:Q:

sz Q <T>
0 0 2S
0 1 4S
1 0 RESERVED
1 1 2D
<Vn>

Is the name of the SIMD&FP source register, encoded in the "Rn" field.

Operation

CheckFPAdvSIMDEnabled64(); bits(datasize) operand = V[n, datasize]; boolean merge = elements == 1 && IsMerging(FPCR); bits(128) result = if merge then V[d, 128] else Zeros(128); FPRounding rounding = FPRoundingMode(FPCR); bits(esize) element; for e = 0 to elements-1 element = Elem[operand, e, esize]; Elem[result, e, esize] = FixedToFP(element, 0, unsigned, FPCR, rounding, esize); V[d, 128] = result;


Internal version only: aarchmrs v2024-03_relA, pseudocode v2024-03_rel, sve v2024-03_rel ; Build timestamp: 2024-03-26T09:45

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