function Float2String($floatvalue, $bits)
{
// http://www.scri.fsu.edu/~jac/MAD3401/Backgrnd/ieee-expl.html
switch ($bits) {
case 32:
$exponentbits = 8;
$fractionbits = 23;
break;
case 64:
$exponentbits = 11;
$fractionbits = 52;
break;
default:
return false;
break;
}
if ($floatvalue >= 0) {
$signbit = '0';
} else {
$signbit = '1';
}
$normalizedbinary = NormalizeBinaryPoint(Float2BinaryDecimal($floatvalue), $fractionbits);
$biasedexponent = pow(2, $exponentbits - 1) - 1 + $normalizedbinary['exponent'];
// (127 or 1023) +/- exponent
$exponentbitstring = str_pad(decbin($biasedexponent), $exponentbits, '0', STR_PAD_LEFT);
$fractionbitstring = str_pad(substr($normalizedbinary['normalized'], 2), $fractionbits, '0', STR_PAD_RIGHT);
return BigEndian2String(Bin2Dec($signbit . $exponentbitstring . $fractionbitstring), $bits % 8, false);
}
function Float2String($floatvalue, $bits)
{
// http://www.scri.fsu.edu/~jac/MAD3401/Backgrnd/ieee-expl.html
if ($bits != 32 && $bits != 64) {
return FALSE;
} else {
if ($bits == 32) {
$exponentbits = 8;
$fractionbits = 23;
} else {
if ($bits == 64) {
$exponentbits = 11;
$fractionbits = 52;
}
}
}
if ($floatvalue >= 0) {
$signbit = '0';
} else {
$signbit = '1';
}
$normalizedbinary = NormalizeBinaryPoint(Float2BinaryDecimal($floatvalue), $fractionbits);
$biasedexponent = pow(2, $exponentbits - 1) - 1 + $normalizedbinary['exponent'];
// (127 or 1023) +/- exponent
$exponentbitstring = str_pad(decbin($biasedexponent), $exponentbits, '0', STR_PAD_LEFT);
$fractionbitstring = str_pad(substr($normalizedbinary['normalized'], 2), $fractionbits, '0', STR_PAD_RIGHT);
return BigEndian2String(Bin2Dec($signbit . $exponentbitstring . $fractionbitstring), $bits % 8, FALSE);
}
