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Altera_Forum's avatar
Altera_Forum
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15 years ago

Modelsim and altfp blocks

I'm attempting to simulate (functional level) a VHDL design using ModelSim that contains altfp_div and an altfp_conv blocks from the altera_mf library. These compile fine in Quartus, but when I try to compile the VHDL in Modelsim it gives me an error because the Modelsim altera_mf library does not contain any altfp blocks except altfp_mult.

Is there any way to add the missing altfp blocks to the Modelsim libary, or is this a limitation of the starter edition of ModelSim-Altera?

5 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    i'm not seeing the same results as you. i'm using Quartus II 9.1sp2 and the accompanying ModelSim-AE version.

    i do confirm that altera_mf only contains an altfp_mult, but the altfp_div.vhd i created with the MegaWizard does compile fine in ModelSim. 

    vcom -reportprogress 300 -work work /home/thepancake/testfp/testfp.vhd
#  Model Technology ModelSim ALTERA vcom 6.5b Compiler 2009.10 Oct  1 2009
#  -- Loading package standard
#  -- Loading package std_logic_1164
#  -- Compiling entity testfp_altfp_div_pst_tre
#  -- Compiling architecture rtl of testfp_altfp_div_pst_tre
#  -- Compiling entity testfp_altfp_div_8ah
#  -- Compiling architecture rtl of testfp_altfp_div_8ah
#  -- Compiling entity testfp
#  -- Compiling architecture rtl of testfp
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    I'm instantiating the altfp_div block in VHDL directly without using the megawizard: 

    LIBRARY altera_mf; 
USE altera_mf.altera_mf_components.all;
...
div0: altfp_div
    GENERIC MAP
    (
	WIDTH_EXP => FP_WIDTH_EXP,
	WIDTH_MAN => FP_WIDTH_MAN,
	ROUNDING => "TO_NEAREST",
	REDUCED_FUNCTIONALITY => "YES",
	PIPELINE => FP_DIV_PIPELINE,
	EXCEPTION_HANDLING => "NO",
	OPTIMIZE => FP_DIV_OPTIMIZATION
    )
    PORT MAP
    (
        clock => clk,
        clk_en => calc_en,
        aclr => clr,
        
        dataa => inputs.if,
        datab => inputs.rf,
        
        result => rfDivRes
    );
...

    This works fine in Quartus II 9.1. The component declaration for altfp_div is in the altera_mf_components package file (comes with Quartus). I generally use this style of coding so that I can easily change any of the parameters for the div block from parameters from the parent.
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    I see your problem - I only have altfp_mult in the altera_mf library too. Raise a case via mysupport.

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    I created a mysupport for this and got the following response:

    There is no behavioral model for altfp_div in the simulation library, thus you will need to include the MegaWizard instantiation in your source RTL for RTL (functional) simulation. Otherwise, you can try to run a Gate Level simulation to verify your design.