用LUA如何实现在IEEE754标准下的16进制和10进制浮点数的相互转换方法

Question

lua中有没有类似java中
String s="3E322D0E";
Float value = Float.intBitsToFloat(Integer.valueOf(s.trim(), 16));
这个方法，去得到浮点数。

Answer 1

function tobinary32(num)
local tmp = num
local str = ""
repeat
if tmp % 2 == 1 then
str = str.."1"
else
str = str.."0"
end
tmp = math.modf(tmp/2)
until(tmp == 0)
str = string.reverse(str)
local lens = string.len(str)
local as = 32 - lens
if as < 0 then

elseif as > 0 then
for i=1,as do
str = "0"..str
end
end

return str
end
function hexToFloat( hexString )
local tmpNum = tobinary32(tonumber(hexString,16))

local sign = string.sub(tmpNum,1,1)
sign = tonumber(sign)
local exponent = string.sub(tmpNum,2,9)
exponent = tonumber(exponent,2) - 127
local mantissa = string.sub(tmpNum,10)
mantissa = tonumber(mantissa,2)
for i=1,23 do
mantissa = mantissa / 2
end
mantissa = 1+mantissa
-- print(mantissa)
local result = (-1)^sign * mantissa * 2^exponent
return result
end

local tmp1 = "42788000"

print(hexToFloat(tmp1))
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作者：___Eirc
来源：CSDN
原文：https://blog.csdn.net/u013625451/article/details/96320498
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