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Line 1... |
-------------------------------------------------------------------------------
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-------------------------------------------------------------------------------
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--
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--
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-- The Arithmetic Logic Unit (ALU).
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-- The Arithmetic Logic Unit (ALU).
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-- It contains the ALU core plus the Accumulator and the Temp Reg.
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-- It contains the ALU core plus the Accumulator and the Temp Reg.
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--
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--
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-- $Id: alu.vhd,v 1.5 2004-04-06 20:21:53 arniml Exp $
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-- $Id: alu.vhd,v 1.6 2004-04-07 20:56:23 arniml Exp $
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--
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--
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-- Copyright (c) 2004, Arnim Laeuger (arniml@opencores.org)
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-- Copyright (c) 2004, Arnim Laeuger (arniml@opencores.org)
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--
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--
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-- All rights reserved
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-- All rights reserved
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--
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--
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add_result_s <= result_v;
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add_result_s <= result_v;
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-- Auxiliary Carry --------------------------------------------------------
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-- Auxiliary Carry --------------------------------------------------------
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aux_c_v := in_a_s(4) & in_b_s(4);
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aux_c_v := in_a_s(4) & in_b_s(4);
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aux_carry_o <= '0';
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case aux_c_v is
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case aux_c_v is
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when "00" | "11" =>
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when "00" | "11" =>
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if result_v(4) = '1' then
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if result_v(4) = '1' then
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aux_carry_o <= '1';
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aux_carry_o <= '1';
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end if;
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end if;
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if result_v(4) = '0' then
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if result_v(4) = '0' then
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aux_carry_o <= '1';
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aux_carry_o <= '1';
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end if;
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end if;
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when others =>
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when others =>
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aux_carry_o <= '0';
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null;
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null;
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end case;
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end case;
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end process adder;
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end process adder;
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-------------------------------------------------------------------------------
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-------------------------------------------------------------------------------
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-- File History:
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-- File History:
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--
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--
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-- $Log: not supported by cvs2svn $
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-- $Log: not supported by cvs2svn $
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-- Revision 1.5 2004/04/06 20:21:53 arniml
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-- fix sensitivity list
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--
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-- Revision 1.4 2004/04/06 18:10:41 arniml
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-- Revision 1.4 2004/04/06 18:10:41 arniml
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-- rework adder and force resource sharing between ADD, INC and DEC
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-- rework adder and force resource sharing between ADD, INC and DEC
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--
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--
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-- Revision 1.3 2004/04/04 14:18:52 arniml
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-- Revision 1.3 2004/04/04 14:18:52 arniml
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-- add measures to implement XCHD
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-- add measures to implement XCHD
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