1682       two54 = 1.80143985094819840000e+16,  /* 43500000 00000000 */  in log()  local
1703       return -two54 / vzero;           /* log(+-0)=-inf */  in log()
1706     x *= two54; /* subnormal number, scale up x */  in log()
1825       two54 = 1.80143985094819840000e+16,  /* 43500000 00000000 */  in log1p()  local
1847         return -two54 / vzero; /* log1p(-1)=+inf */  in log1p()
1852       if (two54 + x > zero    /* raise inexact */  in log1p()
2014       two54 = 1.80143985094819840000e+16,   /* 0x43500000, 0x00000000 */  in log2()  local
2030       return -two54 / vzero;           /* log(+-0)=-inf */  in log2()
2033     x *= two54; /* subnormal number, scale up x */  in log2()
2120       two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */  in log10()  local
2137       return -two54 / vzero;           /* log(+-0)=-inf */  in log10()
2140     x *= two54; /* subnormal number, scale up x */  in log10()