Whati is p in const float Q31_MAX_F = 0x0.FFFFFFp0F;? Generally what is a, b and c in 0xa.bpc?
Does this expression explicitely define binary stored in float32_t?
I have serached for it in web but doesn't find anything.
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mohammadsdtmnd
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1See here: https://stackoverflow.com/questions/4825824/hexadecimal-floating-constant-in-c – Armandas Mar 06 '22 at 06:51
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@Armandas thx then this is a duplicate. – mohammadsdtmnd Mar 06 '22 at 06:52
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But I still not completely understand. – mohammadsdtmnd Mar 06 '22 at 07:27
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The F at the end of 0x0.FFFFFFp0F makes this interesting.
What is p in
const float Q31_MAX_F = 0x0.FFFFFFp0F;?
p is the exponential indicator for some floating point hexadecimal * 2decimal power of 2.
It is 0x0.FFFFFF * pdecimal power of 2, not some hexadecimal exponent 0F.
F at the end of 0x0.FFFFFFp0F (more commonly an f) indicates the constant is a float and not a double. The F is not part of the exponent. The value is 0x0.FFFFFF*pow(2,0) or exactly 0.999999940395355224609375
Generally what is a, b and c in 0xa.bpc?
With 0x0.FFFFFFp0F, a is 0, b is the hexadecimal fraction 0.FFFFFF or 16,777,215/16,777,216 or 0.999999940395355224609375 and c is 0.
Does this expression explicitly define binary stored in
float32_t?
With an F or f suffix, 0x0.FFFFFFp0F is a constant of type float.
float32_t is not a standard C type.
chux - Reinstate Monica
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Could you please update your question for general form according to my update? I can't understand what is `p^(decimal power of 2)` – mohammadsdtmnd Mar 06 '22 at 07:22
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1`F` in `p0F` indicate the constant is a `float` and not a `double`. It is not part of the exponent. The _value_ is `0x0.FFFFFF*pow(2,0)` – chux - Reinstate Monica Mar 06 '22 at 07:42