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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <HTML> <HEAD> <TITLE>html/Listing_of_data_path.vhd</TITLE> <META NAME="generator" CONTENT="HTML::TextToHTML v2.46"> <LINK REL="stylesheet" TYPE="text/css" HREF="lecture.css"> </HEAD> <BODY> <P><table class="ttop"><th class="tpre"><a href="15_Listing_of_data_mem.vhd.html">Previous Lesson</a></th><th class="ttop"><a href="toc.html">Table of Content</a></th><th class="tnxt"><a href="17_Listing_of_io.vhd.html">Next Lesson</a></th></table> <hr> <H1><A NAME="section_1">16 LISTING OF data_path.vhd</A></H1> <pre class="vhdl"> 1 ------------------------------------------------------------------------------- 2 -- 3 -- Copyright (C) 2009, 2010 Dr. Juergen Sauermann 4 -- 5 -- This code is free software: you can redistribute it and/or modify 6 -- it under the terms of the GNU General Public License as published by 7 -- the Free Software Foundation, either version 3 of the License, or 8 -- (at your option) any later version. 9 -- 10 -- This code is distributed in the hope that it will be useful, 11 -- but WITHOUT ANY WARRANTY; without even the implied warranty of 12 -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 -- GNU General Public License for more details. 14 -- 15 -- You should have received a copy of the GNU General Public License 16 -- along with this code (see the file named COPYING). 17 -- If not, see http://www.gnu.org/licenses/. 18 -- 19 ------------------------------------------------------------------------------- 20 ------------------------------------------------------------------------------- 21 -- 22 -- Module Name: data_path - Behavioral 23 -- Create Date: 13:24:10 10/29/2009 24 -- Description: the data path of a CPU. 25 -- 26 ------------------------------------------------------------------------------- 27 -- 28 library IEEE; 29 use IEEE.std_logic_1164.ALL; 30 use IEEE.std_logic_ARITH.ALL; 31 use IEEE.std_logic_UNSIGNED.ALL; 32 33 use work.common.ALL; 34 35 entity data_path is 36 port( I_CLK : in std_logic; 37 38 I_ALU_OP : in std_logic_vector( 4 downto 0); 39 I_AMOD : in std_logic_vector( 5 downto 0); 40 I_BIT : in std_logic_vector( 3 downto 0); 41 I_DDDDD : in std_logic_vector( 4 downto 0); 42 I_DIN : in std_logic_vector( 7 downto 0); 43 I_IMM : in std_logic_vector(15 downto 0); 44 I_JADR : in std_logic_vector(15 downto 0); 45 I_OPC : in std_logic_vector(15 downto 0); 46 I_PC : in std_logic_vector(15 downto 0); 47 I_PC_OP : in std_logic_vector( 2 downto 0); 48 I_PMS : in std_logic; -- program memory select 49 I_RD_M : in std_logic; 50 I_RRRRR : in std_logic_vector( 4 downto 0); 51 I_RSEL : in std_logic_vector( 1 downto 0); 52 I_WE_01 : in std_logic; 53 I_WE_D : in std_logic_vector( 1 downto 0); 54 I_WE_F : in std_logic; 55 I_WE_M : in std_logic_vector( 1 downto 0); 56 I_WE_XYZS : in std_logic; 57 58 Q_ADR : out std_logic_vector(15 downto 0); 59 Q_DOUT : out std_logic_vector( 7 downto 0); 60 Q_INT_ENA : out std_logic; 61 Q_LOAD_PC : out std_logic; 62 Q_NEW_PC : out std_logic_vector(15 downto 0); 63 Q_OPC : out std_logic_vector(15 downto 0); 64 Q_PC : out std_logic_vector(15 downto 0); 65 Q_RD_IO : out std_logic; 66 Q_SKIP : out std_logic; 67 Q_WE_IO : out std_logic); 68 end data_path; 69 70 architecture Behavioral of data_path is 71 72 component alu 73 port ( I_ALU_OP : in std_logic_vector( 4 downto 0); 74 I_BIT : in std_logic_vector( 3 downto 0); 75 I_D : in std_logic_vector(15 downto 0); 76 I_D0 : in std_logic; 77 I_DIN : in std_logic_vector( 7 downto 0); 78 I_FLAGS : in std_logic_vector( 7 downto 0); 79 I_IMM : in std_logic_vector( 7 downto 0); 80 I_PC : in std_logic_vector(15 downto 0); 81 I_R : in std_logic_vector(15 downto 0); 82 I_R0 : in std_logic; 83 I_RSEL : in std_logic_vector( 1 downto 0); 84 85 Q_FLAGS : out std_logic_vector( 9 downto 0); 86 Q_DOUT : out std_logic_vector(15 downto 0)); 87 end component; 88 89 signal A_DOUT : std_logic_vector(15 downto 0); 90 signal A_FLAGS : std_logic_vector( 9 downto 0); 91 92 component register_file 93 port ( I_CLK : in std_logic; 94 95 I_AMOD : in std_logic_vector( 5 downto 0); 96 I_COND : in std_logic_vector( 3 downto 0); 97 I_DDDDD : in std_logic_vector( 4 downto 0); 98 I_DIN : in std_logic_vector(15 downto 0); 99 I_FLAGS : in std_logic_vector( 7 downto 0); 100 I_IMM : in std_logic_vector(15 downto 0); 101 I_RRRR : in std_logic_vector( 4 downto 1); 102 I_WE_01 : in std_logic; 103 I_WE_D : in std_logic_vector( 1 downto 0); 104 I_WE_F : in std_logic; 105 I_WE_M : in std_logic; 106 I_WE_XYZS : in std_logic; 107 108 Q_ADR : out std_logic_vector(15 downto 0); 109 Q_CC : out std_logic; 110 Q_D : out std_logic_vector(15 downto 0); 111 Q_FLAGS : out std_logic_vector( 7 downto 0); 112 Q_R : out std_logic_vector(15 downto 0); 113 Q_S : out std_logic_vector( 7 downto 0); 114 Q_Z : out std_logic_vector(15 downto 0)); 115 end component; 116 117 signal F_ADR : std_logic_vector(15 downto 0); 118 signal F_CC : std_logic; 119 signal F_D : std_logic_vector(15 downto 0); 120 signal F_FLAGS : std_logic_vector( 7 downto 0); 121 signal F_R : std_logic_vector(15 downto 0); 122 signal F_S : std_logic_vector( 7 downto 0); 123 signal F_Z : std_logic_vector(15 downto 0); 124 125 component data_mem 126 port ( I_CLK : in std_logic; 127 128 I_ADR : in std_logic_vector(10 downto 0); 129 I_DIN : in std_logic_vector(15 downto 0); 130 I_WE : in std_logic_vector( 1 downto 0); 131 132 Q_DOUT : out std_logic_vector(15 downto 0)); 133 end component; 134 135 signal M_DOUT : std_logic_vector(15 downto 0); 136 137 signal L_DIN : std_logic_vector( 7 downto 0); 138 signal L_WE_SRAM : std_logic_vector( 1 downto 0); 139 signal L_FLAGS_98 : std_logic_vector( 9 downto 8); 140 141 begin 142 143 alui : alu 144 port map( I_ALU_OP => I_ALU_OP, 145 I_BIT => I_BIT, 146 I_D => F_D, 147 I_D0 => I_DDDDD(0), 148 I_DIN => L_DIN, 149 I_FLAGS => F_FLAGS, 150 I_IMM => I_IMM(7 downto 0), 151 I_PC => I_PC, 152 I_R => F_R, 153 I_R0 => I_RRRRR(0), 154 I_RSEL => I_RSEL, 155 156 Q_FLAGS => A_FLAGS, 157 Q_DOUT => A_DOUT); 158 159 regs : register_file 160 port map( I_CLK => I_CLK, 161 162 I_AMOD => I_AMOD, 163 I_COND(3) => I_OPC(10), 164 I_COND(2 downto 0)=> I_OPC(2 downto 0), 165 I_DDDDD => I_DDDDD, 166 I_DIN => A_DOUT, 167 I_FLAGS => A_FLAGS(7 downto 0), 168 I_IMM => I_IMM, 169 I_RRRR => I_RRRRR(4 downto 1), 170 I_WE_01 => I_WE_01, 171 I_WE_D => I_WE_D, 172 I_WE_F => I_WE_F, 173 I_WE_M => I_WE_M(0), 174 I_WE_XYZS => I_WE_XYZS, 175 176 Q_ADR => F_ADR, 177 Q_CC => F_CC, 178 Q_D => F_D, 179 Q_FLAGS => F_FLAGS, 180 Q_R => F_R, 181 Q_S => F_S, -- Q_Rxx(F_ADR) 182 Q_Z => F_Z); 183 184 sram : data_mem 185 port map( I_CLK => I_CLK, 186 187 I_ADR => F_ADR(10 downto 0), 188 I_DIN => A_DOUT, 189 I_WE => L_WE_SRAM, 190 191 Q_DOUT => M_DOUT); 192 193 -- remember A_FLAGS(9 downto 8) (within the current instruction). 194 -- 195 flg98: process(I_CLK) 196 begin 197 if (rising_edge(I_CLK)) then 198 L_FLAGS_98 <= A_FLAGS(9 downto 8); 199 end if; 200 end process; 201 202 -- whether PC shall be loaded with NEW_PC or not. 203 -- I.e. if a branch shall be taken or not. 204 -- 205 process(I_PC_OP, F_CC) 206 begin 207 case I_PC_OP is 208 when PC_BCC => Q_LOAD_PC <= F_CC; -- maybe (PC on I_JADR) 209 when PC_LD_I => Q_LOAD_PC <= '1'; -- yes: new PC on I_JADR 210 when PC_LD_Z => Q_LOAD_PC <= '1'; -- yes: new PC in Z 211 when PC_LD_S => Q_LOAD_PC <= '1'; -- yes: new PC on stack 212 when others => Q_LOAD_PC <= '0'; -- no. 213 end case; 214 end process; 215 216 -- whether the next instruction shall be skipped or not. 217 -- 218 process(I_PC_OP, L_FLAGS_98, F_CC) 219 begin 220 case I_PC_OP is 221 when PC_BCC => Q_SKIP <= F_CC; -- if cond met 222 when PC_LD_I => Q_SKIP <= '1'; -- yes 223 when PC_LD_Z => Q_SKIP <= '1'; -- yes 224 when PC_LD_S => Q_SKIP <= '1'; -- yes 225 when PC_SKIP_Z => Q_SKIP <= L_FLAGS_98(8); -- if Z set 226 when PC_SKIP_T => Q_SKIP <= L_FLAGS_98(9); -- if T set 227 when others => Q_SKIP <= '0'; -- no. 228 end case; 229 end process; 230 231 Q_ADR <= F_ADR; 232 Q_DOUT <= A_DOUT(7 downto 0); 233 Q_INT_ENA <= A_FLAGS(7); 234 Q_OPC <= I_OPC; 235 Q_PC <= I_PC; 236 237 Q_RD_IO <= '0' when (F_ADR < X"20") 238 else (I_RD_M and not I_PMS) when (F_ADR < X"5D") 239 else '0'; 240 Q_WE_IO <= '0' when (F_ADR < X"20") 241 else I_WE_M(0) when (F_ADR < X"5D") 242 else '0'; 243 L_WE_SRAM <= "00" when (F_ADR < X"0060") else I_WE_M; 244 L_DIN <= I_DIN when (I_PMS = '1') 245 else F_S when (F_ADR < X"0020") 246 else I_DIN when (F_ADR < X"005D") 247 else F_S when (F_ADR < X"0060") 248 else M_DOUT(7 downto 0); 249 250 -- compute potential new PC value from Z, (SP), or IMM. 251 -- 252 Q_NEW_PC <= F_Z when I_PC_OP = PC_LD_Z -- IJMP, ICALL 253 else M_DOUT when I_PC_OP = PC_LD_S -- RET, RETI 254 else I_JADR; -- JMP adr 255 256 end Behavioral; 257 <pre class="filename"> src/data_path.vhd </pre></pre> <P> <P><hr><BR> <table class="ttop"><th class="tpre"><a href="15_Listing_of_data_mem.vhd.html">Previous Lesson</a></th><th class="ttop"><a href="toc.html">Table of Content</a></th><th class="tnxt"><a href="17_Listing_of_io.vhd.html">Next Lesson</a></th></table> </BODY> </HTML>
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