Intel Itanium 9150M, Manual

Page: 129 / 420

3:120 Volume 3: Instruction Reference
fpnma
fpnma — Floating-point Parallel Negative Multiply Add
Format: (
qp
) fpnma.
sf f
1
=
f
3
,
f
4
,
f
2
F1
Description:
The pair of products of the pairs of single precision values in the significand fields of FR
f
3
and FR
f
4
are computed to infinite precision, negated, and then the pair of single
precision values in the significand field of FR
f
2
are added to these (negated) products,
again in infinite precision. The resulting values are then rounded to single precision
using the rounding mode specified by FPSR.
sf . rc . The pair of rounded results are stored
in the significand field of FR
f
1
. The exponent field of FR
f
1
is set to the biased exponent
for 2.0
63
(0x1003E) and the sign field of FR
f
1
is set to positive (0).
If any of FR
f
3
, FR
f
4
, or FR
f
2
is a NaTVal, FR
f
1
is set to NaTVal instead of the computed
result.
Note: If
f
2
is f0 in the fpnma instruction, just the IEEE multiply operation (with the
product being negated before rounding) is performed.
The mnemonic values for
sf
are given in Table 2-23 on page 3:56 .
The encodings and interpretation for the status field’s rc are given in Table 5-6 on
page 1:90 .