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[/] [open8_urisc/] [trunk/] [VHDL/] [Open8_pkg.vhd] - Rev 331
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-- Copyright (c)2006,2011,2012,2013,2015,2020 Jeremy Seth Henry -- All rights reserved. -- -- Redistribution and use in source and binary forms, with or without -- modification, are permitted provided that the following conditions are met: -- * Redistributions of source code must retain the above copyright -- notice, this list of conditions and the following disclaimer. -- * Redistributions in binary form must reproduce the above copyright -- notice, this list of conditions and the following disclaimer in the -- documentation and/or other materials provided with the distribution, -- where applicable (as part of a user interface, debugging port, etc.) -- -- THIS SOFTWARE IS PROVIDED BY JEREMY SETH HENRY ``AS IS'' AND ANY -- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED -- WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE -- DISCLAIMED. IN NO EVENT SHALL JEREMY SETH HENRY BE LIABLE FOR ANY -- DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES -- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -- LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND -- ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT -- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF -- THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -- VHDL Units : Open8_pkg -- Description: Contains constant definitions for the Open8 processor -- -- Revision History -- Author Date Change ------------------ -------- --------------------------------------------------- -- Seth Henry 07/22/06 Design Start -- Seth Henry 02/03/12 Updated generics to match current model -- Seth Henry 10/29/15 Migrated type/constant definitions to this file -- Seth Henry 03/09/20 Created new ALU/SP opcodes for handling new RSP -- Seth Henry 03/12/20 Rationalized the naming of the CPU flags to match -- the assembler names. Also removed superfluous -- signals in the ALU and PC records. -- Seth Henry 03/17/20 Added new subtype and constants for external -- GP flags. -- Seth Henry 03/18/20 Added the ceil_log2 function, since it is used in -- memory sizing calculations. -- Seth Henry 04/09/20 Added the I bit to the exported flags for use in -- memory protection schemes. -- Seth Henry 04/16/20 Added the OPEN8_BUS_TYPE record to simplify -- peripheral connections. -- Seth Henry 10/21/20 Modified the write data path to use separate -- enumerated states rather than reuse the .reg field -- to improve performance. -- Seth Henry 10/23/20 Moved CPU internal constants to o8_cpu.vhd library ieee; use ieee.std_logic_1164.all; use ieee.std_logic_arith.all; package Open8_pkg is ------------------------------------------------------------------------------- -- External constants and type declarations -- -- These subtypes can be used with external peripherals to simplify -- connection to the core. ------------------------------------------------------------------------------- -- These must never be changed, as the core requires them to be these static -- values for proper operation. These are ONLY defined here to allow user -- code to dynamically configure itself to match the Open8 core. constant OPEN8_ADDR_WIDTH : integer := 16; -- DON'T EVEN CONTEMPLATE constant OPEN8_DATA_WIDTH : integer := 8; -- CHANGING THESE! subtype ADDRESS_TYPE is std_logic_vector(OPEN8_ADDR_WIDTH - 1 downto 0); subtype DATA_TYPE is std_logic_vector(OPEN8_DATA_WIDTH - 1 downto 0); -- Note: INTERRUPT_BUNDLE must be exactly the same width as DATA_TYPE subtype INTERRUPT_BUNDLE is DATA_TYPE; subtype EXT_GP_FLAGS is std_logic_vector(4 downto 0); constant EXT_ISR : integer := 0; constant EXT_GP4 : integer := 1; constant EXT_GP5 : integer := 2; constant EXT_GP6 : integer := 3; constant EXT_GP7 : integer := 4; constant OPEN8_NULLBUS : DATA_TYPE := x"00"; constant Reset_Level : std_logic := '1'; type OPEN8_BUS_TYPE is record Clock : std_logic; Reset : std_logic; uSec_Tick : std_logic; Address : ADDRESS_TYPE; Wr_En : std_logic; Wr_Data : DATA_TYPE; Rd_En : std_logic; GP_Flags : EXT_GP_FLAGS; end record; constant INIT_OPEN8_BUS : OPEN8_BUS_TYPE := ( '0', -- Clock Reset_Level, -- Reset '0', -- uSec_Tick x"0000", -- Address '0', -- Wr_En OPEN8_NULLBUS, -- Wr_Data '0', -- Rd_En "00000" -- GP_Flags ); -- Component declaration -- (assumes a 1K RAM at 0x0000 and ROM at the top of the memory map) component o8_cpu is generic( Program_Start_Addr : ADDRESS_TYPE := x"8000"; -- Initial PC location ISR_Start_Addr : ADDRESS_TYPE := x"FFF0"; -- Bottom of ISR vec's Stack_Start_Addr : ADDRESS_TYPE := x"03FF"; -- Top of Stack Allow_Stack_Address_Move : boolean := false; -- Use Normal v8 RSP Enable_Auto_Increment : boolean := false; -- Modify indexed instr BRK_Implements_WAI : boolean := false; -- BRK -> Wait for Int Enable_NMI : boolean := false; -- Force INTR0 enabled Sequential_Interrupts : boolean := false; -- Interruptable ISRs RTI_Ignores_GP_Flags : boolean := false; -- RTI sets all flags Supervisor_Mode : boolean := false; -- I bit is restricted Unsigned_Index_Offsets : boolean := false; -- Offsets are signed Rotate_Ignores_Carry : boolean := false; -- Rotate thru Carry Default_Interrupt_Mask : DATA_TYPE := x"FF"; -- Enable all Ints Clock_Frequency : real -- Clock Frequency ); port( Clock : in std_logic; PLL_Locked : in std_logic; Halt_Req : in std_logic := '0'; Halt_Ack : out std_logic; Open8_Bus : out OPEN8_BUS_TYPE; Rd_Data : in DATA_TYPE; Interrupts : in INTERRUPT_BUNDLE := x"00" ); end component; -- This function is used to calculate RAM parameters, but is generally -- useful for making things more generic. function ceil_log2 (x : in natural) return natural; end package; package body Open8_pkg is -- The ceil_log2 function returns the minimum register width required to -- hold the supplied integer. function ceil_log2 (x : in natural) return natural is variable retval : natural; begin retval := 1; while ((2**retval) - 1) < x loop retval := retval + 1; end loop; return retval; end function; end package body;
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