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[/] [mkjpeg/] [trunk/] [design/] [quantizer/] [ROMR.vhd] - Rev 61
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-------------------------------------------------------------------------------- -- -- -- V H D L F I L E -- -- COPYRIGHT (C) 2009 -- -- -- -------------------------------------------------------------------------------- -- -- Title : ROMR -- Design : EV_JPEG_ENC -- Author : Michal Krepa -- -------------------------------------------------------------------------------- -- -- File : ROMR.VHD -- Created : Wed Mar 19 21:09 2009 -- -------------------------------------------------------------------------------- -- -- Description : Reciprocal of 1/X where X is 1..255 -- -------------------------------------------------------------------------------- library IEEE; use IEEE.STD_LOGIC_1164.all; use ieee.numeric_std.all; entity ROMR is generic ( ROMADDR_W : INTEGER := 8; ROMDATA_W : INTEGER := 16 ); port( addr : in STD_LOGIC_VECTOR(ROMADDR_W-1 downto 0); clk : in STD_LOGIC; datao : out STD_LOGIC_VECTOR(ROMDATA_W-1 downto 0) ); end ROMR; architecture RTL of ROMR is constant CK : integer := 256*256; type ROMQ_TYPE is array (0 to 2**ROMADDR_W-1) of INTEGER range 0 to 2**ROMDATA_W-1; constant rom : ROMQ_TYPE := ( 0, 65535, 32768, 21845, 16384, 13107, 10923, 9362, 8192, 7282, 6554, 5958, 5461, 5041, 4681, 4369, 4096, 3855, 3641, 3449, 3277, 3121, 2979, 2849, 2731, 2621, 2521, 2427, 2341, 2260, 2185, 2114, 2048, 1986, 1928, 1872, 1820, 1771, 1725, 1680, 1638, 1598, 1560, 1524, 1489, 1456, 1425, 1394, 1365, 1337, 1311, 1285, 1260, 1237, 1214, 1192, 1170, 1150, 1130, 1111, 1092, 1074, 1057, 1040, 1024, 1008, 993, 978, 964, 950, 936, 923, 910, 898, 886, 874, 862, 851, 840, 830, 819, 809, 799, 790, 780, 771, 762, 753, 745, 736, 728, 720, 712, 705, 697, 690, 683, 676, 669, 662, 655, 649, 643, 636, 630, 624, 618, 612, 607, 601, 596, 590, 585, 580, 575, 570, 565, 560, 555, 551, 546, 542, 537, 533, 529, 524, 520, 516, 512, 508, 504, 500, 496, 493, 489, 485, 482, 478, 475, 471, 468, 465, 462, 458, 455, 452, 449, 446, 443, 440, 437, 434, 431, 428, 426, 423, 420, 417, 415, 412, 410, 407, 405, 402, 400, 397, 395, 392, 390, 388, 386, 383, 381, 379, 377, 374, 372, 370, 368, 366, 364, 362, 360, 358, 356, 354, 352, 350, 349, 347, 345, 343, 341, 340, 338, 336, 334, 333, 331, 329, 328, 326, 324, 323, 321, 320, 318, 317, 315, 314, 312, 311, 309, 308, 306, 305, 303, 302, 301, 299, 298, 297, 295, 294, 293, 291, 290, 289, 287, 286, 285, 284, 282, 281, 280, 279, 278, 277, 275, 274, 273, 272, 271, 270, 269, 267, 266, 265, 264, 263, 262, 261, 260, 259, 258, 257 ); signal addr_reg : STD_LOGIC_VECTOR(ROMADDR_W-1 downto 0); begin datao <= STD_LOGIC_VECTOR(TO_UNSIGNED( rom( TO_INTEGER(UNSIGNED(addr_reg)) ), ROMDATA_W)); process(clk) begin if clk = '1' and clk'event then addr_reg <= addr; end if; end process; end RTL;
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