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-- #################################################################################################
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-- #################################################################################################
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-- # << NEORV32 - General Purpose FIFO Component >> #
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-- # << NEORV32 - General Purpose FIFO Component >> #
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-- # ********************************************************************************************* #
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-- # ********************************************************************************************* #
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-- # BSD 3-Clause License #
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-- # BSD 3-Clause License #
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-- # #
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-- # #
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-- # Copyright (c) 2021, Stephan Nolting. All rights reserved. #
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-- # Copyright (c) 2022, Stephan Nolting. All rights reserved. #
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-- # #
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-- # #
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-- # Redistribution and use in source and binary forms, with or without modification, are #
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-- # Redistribution and use in source and binary forms, with or without modification, are #
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-- # permitted provided that the following conditions are met: #
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-- # permitted provided that the following conditions are met: #
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-- # #
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-- # #
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-- # 1. Redistributions of source code must retain the above copyright notice, this list of #
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-- # 1. Redistributions of source code must retain the above copyright notice, this list of #
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assert not (is_power_of_two_f(FIFO_DEPTH) = false) report "NEORV32 CONFIG ERROR: FIFO depth has to be a power of two." severity error;
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assert not (is_power_of_two_f(FIFO_DEPTH) = false) report "NEORV32 CONFIG ERROR: FIFO depth has to be a power of two." severity error;
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-- Access Control -------------------------------------------------------------------------
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-- Access Control -------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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fifo.re <= re_i when (FIFO_SAFE = false) else (re_i and fifo.avail); -- read only if data available
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fifo.re <= re_i when (FIFO_SAFE = false) else (re_i and fifo.avail); -- SAFE = read only if data available
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fifo.we <= we_i when (FIFO_SAFE = false) else (we_i and fifo.free); -- write only if space left
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fifo.we <= we_i when (FIFO_SAFE = false) else (we_i and fifo.free); -- SAFE = write only if space left
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-- FIFO Control ---------------------------------------------------------------------------
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-- FIFO Control ---------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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fifo_control: process(rstn_i, clk_i)
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fifo_control: process(rstn_i, clk_i)
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end if;
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end if;
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end if;
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end if;
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end if;
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end if;
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end process fifo_memory_write;
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end process fifo_memory_write;
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-- asynchronous read --
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-- "asynchronous" read --
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fifo_read_async:
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fifo_read_async:
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if (FIFO_RSYNC = false) generate
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if (FIFO_RSYNC = false) generate
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rdata_o <= fifo.datas when (FIFO_DEPTH = 1) else fifo.data(to_integer(unsigned(fifo.r_pnt(fifo.r_pnt'left-1 downto 0))));
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rdata_o <= fifo.datas when (FIFO_DEPTH = 1) else fifo.data(to_integer(unsigned(fifo.r_pnt(fifo.r_pnt'left-1 downto 0))));
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end generate;
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end generate;
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