Intel ITANIUM ARCHITECTURE - SOFTWARE DEVELOPERS MANUAL VOLUME 1 REV 2.3 Manual page 1027
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frcpa
frcpa — Floating-point Reciprocal Approximation
(
) frcpa.
Format:
qp
sf f
If PR
is 0, PR
Description:
qp
If PR
is 1, the following will occur:
qp
• FR
is either set to an approximation (with a relative error < 2
f
1
reciprocal of FR
FR
or FR
f
2
Unsupported}.
• If FR
f
otherwise, it is set to 0.
• If FR
f
Newton-Raphson iterations to fail to produce the correct IEEE-754 result of FR
, then a Floating-point Exception fault for Software Assist occurs.
f
3
System software is expected to compute the IEEE-754 quotient (FR
the result in FR
• If either FR
result, and PR
The mnemonic values for sf are given in
Operation:
if (PR[qp]) {
fp_check_target_register(f
if (tmp_isrcode = fp_reg_disabled(f
disabled_fp_register_fault(tmp_isrcode, 0);
if (fp_is_natval(FR[f
FR[f
PR[p
} else {
tmp_default_result = frcpa_exception_fault_check(f
if (fp_raise_fault(tmp_fp_env))
if (fp_is_nan_or_inf(tmp_default_result)) {
} else {
3:128
,
=
,
p
f
f
1
2
2
3
is cleared and FR
p
2
, or to the IEEE-754 mandated quotient of FR
f
3
is in the set {-Infinity, -0, Pseudo-zero, +0, +Infinity, NaN,
f
3
is set to the approximation of the reciprocal of FR
1
and FR
are such that the approximation of FR
f
2
3
, and set PR
f
1
or FR
is a NaTVal, FR
f
f
2
3
is cleared.
p
2
]) || fp_is_natval(FR[f
2
] = NATVAL;
1
] = 0;
2
fp_exception_fault(fp_decode_fault(tmp_fp_env));
FR[f
] = tmp_default_result;
1
PR[p
] = 0;
2
num = fp_normalize(fp_reg_read(FR[f
den = fp_normalize(fp_reg_read(FR[f
if (fp_is_inf(num) && fp_is_finite(den)) {
FR[f
] = FP_INFINITY;
1
FR[f
].sign = num.sign ^ den.sign;
1
PR[p
] = 0;
2
} else if (fp_is_finite(num) && fp_is_inf(den)) {
FR[f
] = FP_ZERO;
1
FR[f
].sign = num.sign ^ den.sign;
1
PR[p
] = 0;
2
} else if (fp_is_zero(num) && fp_is_finite(den)) {
FR[f
] = FP_ZERO;
1
FR[f
].sign = num.sign ^ den.sign;
1
PR[p
] = 0;
2
remains unchanged.
f
1
to 0.
p
2
is set to NaTVal instead of the computed
f
1
Table 2-23 on page
);
1
, f
, f
, 0))
1
2
3
])) {
3
]));
2
]));
3
-8.886
) of the
/FR
— if either
f
f
2
3
, then PR
is set to 1;
f
p
3
2
's reciprocal may cause the
f
3
f
/FR
), return
f
f
2
3
3:56.
, f
, sf,
2
3
&tmp_fp_env);
Volume 3: Instruction Reference
F6
/FR
2
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