Intel Itanium 9150M, Manual

Page: 76 / 420

Volume 3: Instruction Reference 3:67
fcmp
fcmp — Floating-point Compare
Format: (
qp
) fcmp.
frel
.
fctype
.
sf p
1
,
p
2
=
f
2
,
f
3
F4
Description:
The two source operands are compared for one of twelve relations specified by
frel
. This
produces a boolean result which is 1 if the comparison condition is true, and 0
otherwise. This result is written to the two predicate register destinations,
p
1
and
p
2
.
The way the result is written to the destinations is determined by the compare type
specified by
fctype
. The allowed types are Normal (or none ) and unc.
The mnemonic values for
sf
are given in Table 2-23 on page 3:56 .
The relations are defined for each of the comparison types in Table 2-27 . Of the twelve
relations, not all are directly implemented in hardware. Some are actually pseudo-ops.
For these, the assembler simply switches the source operand specifiers and/or switches
the predicate target specifiers and uses an implemented relation.
Table 2-26. Floating-point Comparison Types
fctype
PR[ qp ]==0
PR[ qp ]==1
Result==0,
No Source NaTVals
Result==1,
No Source NaTVals
One or More
Source NaTVals
PR[ p
1
] PR[ p
2
] PR[ p
1
] PR[ p
2
] PR[ p
1
] PR[ p
2
] PR[ p
1
] PR[ p
2
]
none 0 1 1 0 0 0
unc 0 0 0 1 1 0 0 0
Table 2-27. Floating-point Comparison Relations
frel
frel Completer
Unabbreviated
Relation Pseudo-op of
Quiet NaN
as Operand
Signals Invalid
eq equal f
2
== f
3
No
lt less than f
2
< f
3
Yes
le less than or equal f
2
<= f
3
Yes
gt greater than f
2
> f
3
lt f
2

f
3
Yes
ge greater than or equal f
2
>= f
3
le f
2

f
3
Yes
unord unordered f
2
? f
3
No
neq not equal !( f
2
== f
3
) eq p
1

p
2
No
nlt not less than !( f
2
< f
3
) lt p
1

p
2
Yes
nle not less than or equal !( f
2
<= f
3
) le p
1

p
2
Yes
ngt not greater than !( f
2
> f
3
) lt f
2

f
3
p
1

p
2
Yes
nge not greater than or equal !( f
2
>= f
3
) le f
2

f
3
p
1

p
2
Yes
ord ordered !( f
2
? f
3
) unord p
1

p
2
No