
TM1300 Data Book
Philips Semiconductors
A-88
PRODUCT SPECIFICATION
Convert floating-point to integer with round
toward zero
SYNTAX
[ IF rguard ] ifixrz rsrc1
→
rdest
FUNCTION
if
rguard
then {
rdest
←
(long) ((float)rsrc1)
}
ATTRIBUTES
Function unit
Operation code
Number of operands
Modifier
Modifier range
Latency
Issue slots
falu
21
1
No
—
3
1, 4
DESCRIPTION
The
ifixrz
operation converts the single-precision IEEE floating-point value in rsrc1to a signed integer and writes
the result into rdest Rounding toward zero is performed; the IEEE rounding mode bits in PCSW are ignored. This is
the preferred rounding for ANSI C. If rsrc1 is denormalized, zero is substituted before conversion, and the IFZ flag in
the PCSW is set. If
ifixrz
causes an IEEE exception, such as overflow or underflow, 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
ifixrzflags
operation computes the exception flags that would result from an individual
ifixrz
.
The
ifixrz
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 = 0x40400000 (3.0)
r35 = 0x40247ae1 (2.57)
r10 = 0,
r40 = 0xff4fffff (–3.402823466e+38)
r20 = 1,
r40 = 0xff4fffff (–3.402823466e+38)
ifixrz r30
→
r100
ifixrz r35
→
r102
IF r10 ifixrz r40
→
r105
r100
←
3
r102
←
2, INX flag set
no change, since guard is false
IF r20 ifixrz r40
→
r110
r110
←
0x80000000 (-2
31
), INV flag
set
r112
←
0x7fffffff (2
31
-1), INV flag set
r115
←
-1, INX flag set
r117
←
0, IFZ set
r120
←
0, INV flag set
r122
←
0, INV flag set
r45 = 0x7f800000 (+INF))
ifixrz r45
→
r112
ifixrz r50
→
r115
ifixrz r60
→
r117
ifixrz r70
→
r120
ifixrz r80
→
r122
r50 = 0xbfc147ae (-1.51)
r60 = 0x00400000 (5.877471754e-39)
r70 = 0xffffffff (QNaN)
r80 = 0xffbfffff (SNaN)
SEE ALSO
ifixieee ufixieee ufixrz
ifixrz