Intel Itanium 9150M, Manual

Page: 105 / 420

3:96 Volume 3: Instruction Reference
fpack
fpack — Floating-point Pack
Format: (
qp
) fpack
f
1
=
f
2
,
f
3
pack_form F9
Description:
The register format numbers in FR
f
2
and FR
f
3
are converted to single precision memory
format. These two single precision numbers are concatenated and 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 either FR
f
2
or FR
f
3
is a NaTVal, FR
f
1
is set to NaTVal instead of the computed result.
Operation: if (PR[ qp ]) {
fp_check_target_register( f
1
);
if (tmp_isrcode = fp_reg_disabled( f
1
, f
2
, f
3
, 0))
disabled_fp_register_fault(tmp_isrcode, 0);
if (fp_is_natval(FR[ f
2
]) || fp_is_natval(FR[ f
3
])) {
FR[ f
1
] = NATVAL;
} else {
tmp_res_hi = fp_single(FR[ f
2
]);
tmp_res_lo = fp_single(FR[ f
3
]);
FR[ f
1
].significand = fp_concatenate(tmp_res_hi, tmp_res_lo);
FR[ f
1
].exponent = FP_INTEGER_EXP;
FR[ f
1
].sign = FP_SIGN_POSITIVE;
}
fp_update_psr(
f
1
);
}
FP Exceptions:
None
Interruptions:
Illegal Operation fault Disabled Floating-point Register fault
Figure 2-14. Floating-point Pack
81 0 80 64 63 81 0 80 64 63
81 0 80 64 63
FR
f
2
FR
f
3
FR
f
1
0
1003E
32 31
82-bit FR to Single Mem Format Conversions