3.4.2 ieee_values(3m)
无穷大、NaN、最大和最小正浮点数等 IEEE 值是由 ieee_values(3m) 手册页中介绍的函数提供的。 Table 3–9、Table 3–10、Table 3–11 和Table 3–12 中显示了 ieee_values(3m) 函数提供的值的十进制值及其十六进制 IEEE 表示形式。
表 3-9 IEEE 值:单精度
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最大正规数 |
3.40282347e+38 7f7fffff |
r = max_normalf(); r = r_max_normal() |
最小正规数 |
1.17549435e–38 00800000 |
r = min_normalf(); r = r_min_normal() |
最大次正规数 |
1.17549421e–38 007fffff |
r = max_subnormalf(); r = r_max_subnormal() |
最小次正规数 |
1.40129846e–45 00000001 |
r = min_subnormalf(); r = r_min_subnormal() |
∞ |
Infinity 7f800000 |
r = infinityf(); r = r_infinity() |
quiet NaN(静态 NaN) |
NaN 7fffffff |
r = quiet_nanf(0); r = r_quiet_nan(0) |
信号 NaN |
NaN 7f800001 |
r = signaling_nanf(0); r = r_signaling_nan(0) |
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表 3-10 IEEE 值:双精度
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最大正规数 |
1.7976931348623157e+308
7fefffff ffffffff |
d = max_normal(); d = d_max_normal() |
最小正规数 |
2.2250738585072014e–308
00100000 00000000 |
d = min_normal(); d = d_min_normal() |
最大次正规数 |
2.2250738585072009e–308
000fffff ffffffff |
d = max_subnormal(); d = d_max_subnormal() |
最小次正规数 |
4.9406564584124654e–324
00000000 00000001 |
d = min_subnormal(); d = d_min_subnormal() |
∞
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Infinity
7ff00000 00000000 |
d = infinity(); d = d_infinity() |
quiet NaN(静态 NaN) |
NaN
7fffffff ffffffff |
d = quiet_nan(0); d = d_quiet_nan(0) |
信号 NaN |
NaN
7ff00000 00000001 |
d = signaling_nan(0); d = d_signaling_nan(0) |
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表 3-11 IEEE 值:四倍精度
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最大正规数 |
1.1897314953572317650857593266280070e+4932
7ffeffff ffffffff ffffffff ffffffff |
q = max_normall(); q = q_max_normal() |
最小正规数 |
3.3621031431120935062626778173217526e–4932
00010000 00000000 00000000 00000000 |
q = min_normall(); q = q_min_normal() |
最大次正规数 |
3.3621031431120935062626778173217520e–4932
0000ffff ffffffff ffffffff ffffffff |
q = max_subnormall(); q = q_max_subnormal() |
最小次正规数 |
6.4751751194380251109244389582276466e–4966
00000000 00000000 00000000 00000001 |
q = min_subnormall(); q = q_min_subnormal() |
∞
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Infinity
7fff0000 00000000 00000000 00000000 |
q = infinityl(); q = q_infinity() |
quiet NaN(静态 NaN) |
NaN
7fff8000 00000000 00000000 00000000 |
q = quiet_nanl(0); q = q_quiet_nan(0) |
信号 NaN |
NaN
7fff0000 00000000 00000000 00000001 |
q = signaling_nanl(0); q = q_signaling_nan(0) |
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表 3-12 IEEE 值:双扩展精度 (x86)
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最大正规数 |
1.18973149535723176505e+4932
7ffe ffffffff ffffffff |
x = max_normall(); |
最小正正规数 |
3.36210314311209350626e–4932
0001 80000000 00000000 |
x = min_normall(); |
最大次正规数 |
3.36210314311209350608e–4932
0000 7fffffff ffffffff |
x = max_subnormall(); |
最小正次正规数 |
1.82259976594123730126e–4951
0000 00000000 00000001 |
x = min_subnormall(); |
∞
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Infinity
7fff 80000000 00000000 |
x = infinityl(); |
quiet NaN(静态 NaN) |
NaN
7fff c0000000 00000000 |
x = q |
信号 NaN |
NaN
7fff 80000000 00000001 |
x = signaling_nanl(0); |
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