FCVTZU (vector, fixed-point)
Floating-point convert to unsigned fixed-point, rounding toward zero (vector)
This instruction converts a scalar or each element in a vector
from floating-point to
fixed-point unsigned integer
using the Round towards Zero rounding mode, and
writes the result to the general-purpose 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 2 classes:
Scalar
and
Vector
0
1
1
1
1
1
1
1
0
!= 0000
1
1
1
1
1
1
FCVTZU <V><d>, <V><n>, #<fbits>
if immh IN {'000x'} || (immh IN {'001x'} && !IsFeatureImplemented(FEAT_FP16)) then UNDEFINED;
constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer esize = if immh IN {'1xxx'} then 64 else if immh IN {'01xx'} then 32 else 16;
constant integer datasize = esize;
constant integer elements = 1;
constant integer fracbits = (esize * 2) - UInt(immh:immb);
constant boolean unsigned = TRUE;
constant FPRounding rounding = FPRounding_ZERO;
0
1
0
1
1
1
1
0
!= 0000
1
1
1
1
1
1
FCVTZU <Vd>.<T>, <Vn>.<T>, #<fbits>
if immh == '0000' then SEE(asimdimm);
if immh IN {'000x'} || (immh IN {'001x'} && !IsFeatureImplemented(FEAT_FP16)) then UNDEFINED;
if immh<3>:Q == '10' then UNDEFINED;
constant integer d = UInt(Rd);
constant integer n = UInt(Rn);
constant integer esize = if immh IN {'1xxx'} then 64 else if immh IN {'01xx'} then 32 else 16;
constant integer datasize = 64 << UInt(Q);
constant integer elements = datasize DIV esize;
constant integer fracbits = (esize * 2) - UInt(immh:immb);
constant boolean unsigned = TRUE;
constant FPRounding rounding = FPRounding_ZERO;
<V>
Is a width specifier,
immh
<V>
0001
RESERVED
001x
H
01xx
S
1xxx
D
<d>
Is the number of the SIMD&FP destination register, in the "Rd" field.
<n>
Is the number of the first SIMD&FP source register, encoded in the "Rn" field.
<fbits>
For the scalar variant: is the number of fractional bits, in the range 1 to the operand width,
immh
<fbits>
0001
RESERVED
001x
32 - UInt(immh:immb)
01xx
64 - UInt(immh:immb)
1xxx
128 - UInt(immh:immb)
<fbits>
For the vector variant: is the number of fractional bits, in the range 1 to the element width,
immh
<fbits>
0001
RESERVED
001x
32 - UInt(immh:immb)
01xx
64 - UInt(immh:immb)
1xxx
128 - UInt(immh:immb)
<Vd>
Is the name of the SIMD&FP destination register, encoded in the "Rd" field.
<T>
Is an arrangement specifier,
immh
Q
<T>
0001
x
RESERVED
001x
0
4H
001x
1
8H
01xx
0
2S
01xx
1
4S
1xxx
0
RESERVED
1xxx
1
2D
<Vn>
Is the name of the SIMD&FP source register, encoded in the "Rn" field.
CheckFPAdvSIMDEnabled64();
constant bits(datasize) operand = V[n, datasize];
constant boolean merge = elements == 1 && IsMerging(FPCR);
bits(128) result = if merge then V[d, 128] else Zeros(128);
bits(esize) element;
for e = 0 to elements-1
element = Elem[operand, e, esize];
Elem[result, e, esize] = FPToFixed(element, fracbits, unsigned, FPCR, rounding, esize);
V[d, 128] = result;