floating point number

[Altera_Forum]

Hi All, 

 How can I convert a std_logic_vector number into a floating point number?  What is the command-operator? what library to use? is it synthesizable ?   Thanks

[Altera_Forum]

If you want a synthesisable fp number you will have to use slv and user the floating point cores provided by altera. But why do you want floating point? Usually fire FPGAs it is far more efficient to use fixed point.

[Altera_Forum]

Hi, 

 Do you mean ALTFP_CONVER from the IP library?  If yes, it creates this entity, which is different from documentation. for example: what is "distance" input? Doesn't have this input in documentation.  ENTITY ALTFP_CONVERa_altbarrel_shift_fof IS   PORT   (   aclr : IN STD_LOGIC := '0';  clk_en : IN STD_LOGIC := '1';  clock : IN STD_LOGIC := '0';  data : IN STD_LOGIC_VECTOR (31 DOWNTO 0);  distance : IN STD_LOGIC_VECTOR (4 DOWNTO 0);  result : OUT STD_LOGIC_VECTOR (31 DOWNTO 0)  );   END ALTFP_CONVERa_altbarrel_shift_fof;        Thanks

[Altera_Forum]

That is a altbarrel_shift_fof core.Not fp convert.

[Altera_Forum]

HI, 

I am using version quartus 16.1.0 and this is the vhdl i am getting after generating ALTFP_CONVER.  Maybe a quartus bug. anyway looks like it works.

[Altera_Forum]

Sorry, it doesn't work. I think there is a problem with this IP in quartus 16.1.0. it generates ALTFP_CONVERa_altbarrel_shift_fof instead of ALTFP_CONVER.

[Altera_Forum]

If it is generating that odd looking IP, which looks like the ports for a barrel shifter, you should raise a support ticket with altera..

[Altera_Forum]

hi 

iam doing a project in floting point arithemetics  so i want to separate the mantisa exponent and sign bit form an unsigned integer  anybody have know how to convert and accces by vhdl code/command

[Altera_Forum]

If you want an unsigned integer, you will need to use the alt_fp_convert megafunction

[Altera_Forum]

Of course you can do the conversion in your own code. Float to integer is relative simple arithmetic, just a variable shift.