Type Range Significant digits Size ------------------------------------------------------------------------ ------------------------------------------------------------------------ ------------------------------------------------------------------------ ------------------------------------------------------------------------ Real platform dependant ??? 4 or 8 Single 1.5E-45 .. 3.4E38 7-8 4 Double 5.0E-324 .. 1.7E308 15-16 8 Extended 1.9E-4932 .. 1.1E4932 19-20 10 Comp -2E64+1 .. 2E63-1 19-20 8 Currency -922337203685477.5808 .. 922337203685477.5807 19-20 8

I am trying to figure out the internal representation of these. (So they can be converted, including conversion form sizes not present in fpc) They are all floating point? Pascal has no fixed point? (nevertheless, rules for fixed point may also be of interest) dwarf2 says it is specified in each platforms ABI, but I have not found that (not even found the ABI yet). Only found: http://en.wikipedia.org/wiki/Computer_number_format#Representing_fractions_in_binary And http://www.freepascal.org/docs-html/ref/refsu6.html#x28-310003.1.2 > Type Range Significant digits Size > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------ > > ------------------------------------------------------------------------ > Real platform dependant ??? 4 or 8 > Single 1.5E-45 .. 3.4E38 7-8 4 > Double 5.0E-324 .. 1.7E308 15-16 8 > Extended 1.9E-4932 .. 1.1E4932 19-20 10 > Comp -2E64+1 .. 2E63-1 19-20 8 > Currency -922337203685477.5808 .. 922337203685477.5807 19-20 8 > apparently there also is real46 (never heard of real16) The size will actually be in the dwarf, so that I got. But from that how do I know how many bits are in the exponent? (and how many in the number). Apparently it depends on the CPU? But where to get the info?

On 2/11/2014 4:53 PM, Martin Frb wrote: > I am trying to figure out the internal representation of these. (So > they can be converted, including conversion form sizes not present in > fpc) > > They are all floating point? Pascal has no fixed point? > (nevertheless, rules for fixed point may also be of interest) > > dwarf2 says it is specified in each platforms ABI, but I have not > found that (not even found the ABI yet). > Only found: > http://en.wikipedia.org/wiki/Computer_number_format#Representing_fractions_in_binary > > And http://www.freepascal.org/docs-html/ref/refsu6.html#x28-310003.1.2 > >> Type Range Significant digits Size >> ------------------------------------------------------------------------ >> >> ------------------------------------------------------------------------ >> >> ------------------------------------------------------------------------ >> >> ------------------------------------------------------------------------ >> Real platform dependant ??? 4 or 8 >> Single 1.5E-45 .. 3.4E38 7-8 4 >> Double 5.0E-324 .. 1.7E308 15-16 8 >> Extended 1.9E-4932 .. 1.1E4932 19-20 10 >> Comp -2E64+1 .. 2E63-1 19-20 8 >> Currency -922337203685477.5808 .. 922337203685477.5807 19-20 8 >> > apparently there also is real46 (never heard of real16) > > The size will actually be in the dwarf, so that I got. > > But from that how do I know how many bits are in the exponent? (and > how many in the number). Apparently it depends on the CPU? But where > to get the info? For all but Real48 (not Real46 or Real16), those are conformant with IEEE 754 (http://grouper.ieee.org/groups/754/) Real48 is the non-IEEE754 (predating it) floating point format that was used in the early Borland Turbo Pascal...