
TM1300 Data Book
Philips Semiconductors
A-86
PRODUCT SPECIFICATION
Convert oating-point to integer using PCSW
rounding mode
SYNTAX
[ IF r
guard ] ifixieee rsrc1
→ rdest
FUNCTION
if r
guard then {
r
dest
← (long) ((oat)rsrc1)
}
ATTRIBUTES
Function unit
falu
Operation code
121
Number of operands
1
Modier
No
Modier range
—
Latency
3
Issue slots
1, 4
DESCRIPTION
The ifixieee operation converts the single-precision IEEE oating-point value in r
src1 to a signed integer and
writes the result into r
dest. Rounding is according to the IEEE rounding mode bits in PCSW. If rsrc1 is denormalized,
zero is substituted before conversion, and the IFZ ag in the PCSW is set. If ifixieee causes an IEEE exception,
such as overow or underow, the corresponding exception ags in the PCSW are set. The PCSW exception ags are
sticky: the ags can be set as a side-effect of any oating-point operation but can only be reset by an explicit
writepcsw
operation. The update of the PCSW exception ags occurs at the same time as r
dest is written. If any
other oating-point compute operations update the PCSW at the same time, the net result in each exception ag is the
logical OR of all simultaneous updates ORed with the existing PCSW value for that exception ag.
The ifixieeeflags operation computes the exception ags that would result from an individual ifixieee.
The ifixieee operation optionally takes a guard, specied in r
guard. If a guard is present, its LSB controls the
modication of the destination register. If the LSB of r
guard is 1, rdest and the exception ags in PCSW are written;
otherwise, r
dest is not changed and the operation does not affect the exception ags in PCSW.
EXAMPLES
Initial Values
Operation
Result
r30 = 0x40400000 (3.0)
ifixieee r30
→ r100
r100
← 3
r35 = 0x40247ae1 (2.57)
ifixieee r35
→ r102
r102
← 3, INX ag set
r10 = 0,
r40 = 0xff4fffff (–3.402823466e+38)
IF r10 ifixieee r40
→ r105 no change, since guard is false
r20 = 1,
r40 = 0xff4fffff (–3.402823466e+38)
IF r20 ifixieee r40
→ r110 r110 ← 0x80000000 (-231), INV ag set
r45 = 0x7f800000 (+INF))
ifixieee r45
→ r112
r112
← 0x7fffffff (231-1), INV ag set
r50 = 0xbfc147ae (-1.51)
ifixieee r50
→ r115
r115
← -2, INX ag set
r60 = 0x00400000 (5.877471754e-39)
ifixieee r60
→ r117
r117
← 0, IFZ set
r70 = 0xffffffff (QNaN)
ifixieee r70
→ r120
r120
← 0, INV ag set
r80 = 0xffbfffff (SNaN)
ifixieee r80
→ r122
r122
← 0, INV ag set
SEE ALSO
ufixieee ifixrz ufixrz
ifixieee