![](http://datasheet.mmic.net.cn/260000/PTM1300FBEA_datasheet_15959396/PTM1300FBEA_464.png)
TM1300 Data Book
Philips Semiconductors
A-178
PRODUCT SPECIFICATION
Convert unsigned integer to floating-point
SYNTAX
[ IF rguard ] ufloat rsrc1
→
rdest
FUNCTION
if
rguard
then {
rdest
←
(float) ((unsigned long)rsrc1)
}
ATTRIBUTES
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
falu
127
1
No
—
3
1, 4
DESCRIPTION
The
ufloat
operation converts the unsigned integer value in rsrc1 to single-precision IEEE floating-point format
and writes the result into rdest Rounding is according to the IEEE rounding mode bits in PCSW. If
ufloat
causes an
IEEE exception, such as inexact, the corresponding exception flags in the PCSW are set. The PCSW exception flags
are sticky: the flags can be set as a side-effect of any floating-point operation but can only be reset by an explicit
writepcsw
operation. The update of the PCSW exception flags occurs at the same time as rdest is written. If any
other floating-point compute operations update the PCSW at the same time, the net result in each exception flag is the
logical OR of all simultaneous updates ORed with the existing PCSW value for that exception flag.
The
ufloatflags
operation computes the exception flags that would result from an individual
ufloat
.
The
ufloat
operation optionally takes a guard, specified in rguard If a guard is present, its LSB controls the
modification of the destination register. If the LSB of rguard is 1, rdest and the exception flags in PCSW are written;
otherwise, rdestis not changed and the operation does not affect the exception flags in PCSW.
EXAMPLES
Initial Values
Operation
Result
r30 = 3
r40 = 0xffffffff (4294967295)
r10 = 0, r50 = 0xfffffffd
r20 = 1, r50 = 0xfffffffd
r60 = 0x7fffffff (2147483647)
r70 = 0x80000000 (2147483648)
r80 = 0x7ffffff1 (2147483633)
ufloat r30
→
r100
ufloat r40
→
r105
IF r10 ufloat r50
→
r110
IF r20 ufloat r50
→
r115
ufloat r60
→
r117
ufloat r70
→
r120
ufloat r80
→
r122
r100
←
0x40400000 (3.0)
r105
←
0x4f800000 (4.294967296e+9), INX flag set
no change, since guard is false
r115
←
0x4f800000 (4.294967296e+9), INX flag set
r117
←
0x4f000000 (2.147483648e+9), INX flag set
r120
←
0x4f000000 (2.147483648e+9)
r122
←
0x4f000000 (2.147483648e+9), INX flag set
SEE ALSO
ifloat ifloatrz ufloatrz
ifixieee ufloatflags
ufloat