UltraSPARC User's Manual
Floating-point stores other than
graphics instruction other than
ample:
FADDs f2, f5, f6
STF
f6, [address]
Floating-point stores of the result of an
dependent floating-point instruction.
cannot be dispatched in the two groups following a floating-point or
ST(X)FSR
graphics instruction that references the floating-point registers. For example:
FMULd
STFSR
To simplify critical timing paths, floating-point operations are usually stalled in
the G Stage until earlier floating-point operations with a different precision com-
plete, regardless of data dependency. This behavior is described more precisely in
the following two rules. Floating-point loads and stores are independent of these
mixed precision rules.
1.
A floating-point or graphics instruction that follows an
of different precision break the group, even if there is no data dependency.
For example:
FMOVs
FMULd
2.
A floating-point or graphics instruction following an operation other than
,
FMOV
FABS
N
Stage of the earlier operation, even if there is no data dependency. For
2
example:
FADDs f2, f5, f0
FMULd f2, f2, f2
As an exception to the previous rule,
er operation of different precision, but are stalled until the N
operation otherwise.
Sun Microelectronics
298
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
can store the result of a floating-point or
ST{X}FSR
or
FDIV
FSQRT
G
E
C
N
G
E
C
N
FDIV
G
E
C
N
N
N
1
2
3
G
E
C
G
E
C
N
N
1
G
E
C
N
,
,
,
of different precision is stalled until the
FNEG
FDIV
FSQRT
G
E
FDIV
and be in the same group. For ex-
N
N
W
1
2
3
N
N
W
1
2
3
or
are treated the same as a
FSQRT
W
N
N
N
1
2
3
FMOV
N
W
2
3
N
N
W
1
2
3
C
N
N
N
W
1
2
3
G
E
C
N
1
or
can be grouped with an old-
FSQRT
Stage of the earlier
2
,
,
FABS
FNEG
N
2
Need help?
Do you have a question about the UltraSPARC-I and is the answer not in the manual?