Construct unsigned fixed-point numeric object
a = ufi
a = ufi(v)
a = ufi(v,w)
a = ufi(v,w,f)
a = ufi(v,w,slope,bias)
a = ufi(v,w,slopeadjustmentfactor,fixedexponent,bias)
You can use the ufi constructor function
in the following ways:
a = ufi is the default constructor
and returns an unsigned fi object with no value,
16-bit word length, and 15-bit fraction length.
a = ufi(v) returns an unsigned
fixed-point object with value v, 16-bit word length,
and best-precision fraction length.
a = ufi(v,w) returns an unsigned
fixed-point object with value v, word length w,
and best-precision fraction length.
a = ufi(v,w,f) returns an unsigned
fixed-point object with value v, word length w,
and fraction length f.
a = ufi(v,w,slope,bias) returns
an unsigned fixed-point object with value v, word
length w, slope, and bias.
a = ufi(v,w,slopeadjustmentfactor,fixedexponent,bias) returns
an unsigned fixed-point object with value v, word
length w, slopeadjustmentfactor, fixedexponent,
and bias.
fi objects created by the ufi constructor
function have the following general types of properties:
These properties are described in detail in fi Object Properties in the Properties Reference.
fi objects created by the ufi constructor
function have no local fimath.
The data properties of a fi object are always
writable.
bin — Stored integer value
of a fi object in binary
data — Numerical real-world
value of a fi object
dec — Stored integer value
of a fi object in decimal
double — Real-world value
of a fi object, stored as a MATLAB® double
hex — Stored integer value
of a fi object in hexadecimal
int — Stored integer value
of a fi object, stored in a built-in MATLAB integer
data type. You can also use int8, int16, int32, int64, uint8, uint16, uint32,
and uint64 to get the stored integer value of a fi object
in these formats
oct — Stored integer value
of a fi object in octal
These properties are described in detail in fi Object Properties.
When you create a fi object with the ufi constructor
function, that fi object does not have a local fimath object.
You can attach a fimath object to that fi object
if you do not want to use the default fimath settings. For more information,
see fimath Object Construction in the Fixed-Point
Designer™ documentation.
fimath — fixed-point math
object
The following fimath properties are always
writable and, by transitivity, are also properties of a fi object.
CastBeforeSum — Whether
both operands are cast to the sum data type before addition
This property is hidden when the SumMode is
set to FullPrecision.
OverflowAction — Action
to take on overflow
ProductBias — Bias of the
product data type
ProductFixedExponent — Fixed
exponent of the product data type
ProductFractionLength —
Fraction length, in bits, of the product data type
ProductMode — Defines how
the product data type is determined
ProductSlope — Slope of
the product data type
ProductSlopeAdjustmentFactor —
Slope adjustment factor of the product data type
ProductWordLength — Word
length, in bits, of the product data type
RoundingMethod — Rounding
method
SumBias — Bias of the sum
data type
SumFixedExponent — Fixed
exponent of the sum data type
SumFractionLength — Fraction
length, in bits, of the sum data type
SumMode — Defines how the
sum data type is determined
SumSlope — Slope of the
sum data type
SumSlopeAdjustmentFactor —
Slope adjustment factor of the sum data type
SumWordLength — The word
length, in bits, of the sum data type
These properties are described in detail in fimath Object Properties.
When you create a fi object, a numerictype object
is also automatically created as a property of the fi object.
numerictype — Object containing all
the data type information of a fi object, Simulink® signal
or model parameter
The following numerictype properties are,
by transitivity, also properties of a fi object.
The properties of the numerictype object become
read only after you create the fi object. However,
you can create a copy of a fi object with new values
specified for the numerictype properties.
Bias — Bias of a fi object
DataType — Data type category
associated with a fi object
DataTypeMode — Data type
and scaling mode of a fi object
FixedExponent — Fixed-point
exponent associated with a fi object
SlopeAdjustmentFactor —
Slope adjustment associated with a fi object
FractionLength — Fraction
length of the stored integer value of a fi object
in bits
Scaling — Fixed-point scaling
mode of a fi object
Signed — Whether a fi object
is signed or unsigned
Signedness — Whether a fi object
is signed or unsigned
numerictype objects can have a Signedness of Auto,
but all fi objects must be Signed or Unsigned.
If a numerictype object with Auto Signedness is
used to create a fi object, the Signedness property
of the fi object automatically defaults to Signed.
Slope — Slope associated
with a fi object
WordLength — Word length
of the stored integer value of a fi object in bits
For further details on these properties, see numerictype Object Properties.
For information about the display format of fi objects,
refer to View Fixed-Point Data.
For examples of casting, see Cast fi Objects.
For example, the following creates an unsigned fi object
with a value of pi, a word length of 8 bits, and
a fraction length of 3 bits:
a = ufi(pi,8,3)
a =
3.1250
DataTypeMode: Fixed-point: binary point scaling
Signedness: Unsigned
WordLength: 8
FractionLength: 3Default fimath properties are associated
with a. When a fi object does
not have a local fimath object, no fimath object
properties are displayed in its output. To determine whether a fi object
has a local fimath object, use the isfimathlocal function.
isfimathlocal(a)
ans =
0A returned value of 0 means the fi object
does not have a local fimath object. When the isfimathlocal function
returns a 1, the fi object has
a local fimath object.
The value v can also be an array:
a = ufi((magic(3)/10),16,12)
a =
0.8000 0.1001 0.6001
0.3000 0.5000 0.7000
0.3999 0.8999 0.2000
DataTypeMode: Fixed-point: binary point scaling
Signedness: Unsigned
WordLength: 16
FractionLength: 12
>> If you omit the argument f, it is set automatically
to the best precision possible:
a = ufi(pi,8)
a =
3.1406
DataTypeMode: Fixed-point: binary point scaling
Signedness: Unsigned
WordLength: 8
FractionLength: 6If you omit w and f, they
are set automatically to 16 bits and the best precision possible,
respectively:
a = ufi(pi)
a =
3.1416
DataTypeMode: Fixed-point: binary point scaling
Signedness: Unsigned
WordLength: 16
FractionLength: 14fi | fimath | fipref | isfimathlocal | numerictype | quantizer | sfi