Intel Itanium 9150M, Manual

Page: 287 / 420

3:278 Volume 3: Instruction Reference
xmpy
xmpy — Fixed-Point Multiply
Format: (
qp
) xmpy.l
f
1
=
f
3
,
f
4
pseudo-op of: (
qp
) xma.l
f
1
=
f
3
,
f
4
, f0
(
qp
) xmpy.lu
f
1
=
f
3
,
f
4
pseudo-op of: (
qp
) xma.l
f
1
=
f
3
,
f
4
, f0
(
qp
) xmpy.h
f
1
=
f
3
,
f
4
pseudo-op of: (
qp
) xma.h
f
1
=
f
3
,
f
4,
f0
(
qp
) xmpy.hu
f
1
=
f
3
,
f
4
pseudo-op of: (
qp
) xma.hu
f
1
=
f
3
,
f
4
, f0
Description:
Two source operands (FR
f
3
and FR
f
4
) are treated as either signed or unsigned integers
and multiplied. The upper or lower 64 bits of the resultant product are selected and
placed in FR
f
1
.
In the high_unsigned_form, the significand fields of FR
f
3
and FR
f
4
are treated as
unsigned integers and multiplied to produce a full 128-bit unsigned result. The most
significant 64-bits of the resultant product are placed in the significand field of FR
f
1
.
In the high_form, the significand fields of FR
f
3
and FR
f
4
are treated as signed integers
and multiplied to produce a full 128-bit signed result. The most significant 64-bits of
the resultant product are placed in the significand field of FR
f
1
.
In the other forms, the significand fields of FR
f
3
and FR
f
4
are treated as signed integers
and multiplied to produce a full 128-bit signed result. The least significant 64-bits of the
resultant product are placed in the significand field of FR
f
1
.
In all forms, 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). Note: f1 as an operand is not
an integer 1; it is just the register file format’s 1.0 value.
Operation: See “xma — Fixed-Point Multiply Add” on page 3:276.