git-svn-id: http://moon:8086/svn/vhdl/trunk@1423 cc03376c-175c-47c8-b038-4cd826a8556b
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2021-03-21 11:31:55 +00:00
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--------------------------------------------------------------------------
-- Project: JCPU, a portable 8-bit RISC CPU written in VHDL
-- This file: Types, constants and functions for JCPU
--
-- Copyright (C) 2007 J. Ahrensfeld
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
--
-- For questions and ideas, please contact the author at jens@jayfield.org
--
--------------------------------------------------------------------------
library IEEE;
use IEEE.STD_LOGIC_1164.ALL;
use IEEE.numeric_std.ALL;
package cpu_pkg is
-- Revision of the CPU
constant REVISION : integer := 2;
-- Chipram depth (can be tweaked)
constant CHIPRAM_SIZE_BITS : integer := 10;
-- Chipregister file depth
constant CHIPREG_SIZE_BITS : integer := 8;
-- Number of registers (can be tweaked)
constant REG_SIZE_BITS : integer := 4;
-- Instruction memory
constant IMEM_ADDR_WIDTH : integer := 12;
-- Data memory
constant DMEM_DATA_WIDTH : integer := 8;
constant DMEM_ADDR_WIDTH : integer := 8;
-- Instruction format
constant INST_OPCODE_WIDTH : integer := 6;
constant IMEM_DATA_WIDTH : integer := INST_OPCODE_WIDTH + DMEM_DATA_WIDTH + REG_SIZE_BITS;
-- Microcode ROM
constant MUCODE_ADDR_WIDTH : integer := 9;
-- Stack depth
constant STACK_SIZE_BITS : integer := CHIPRAM_SIZE_BITS-1;
--Types
subtype iphase_t is integer range 0 to 1;
type mem_access_t is (cmem_access, xmem_access, cio_access, xio_access);
type reg_src_t is (alu_src, stk_src, cmem_src, xmem_src);
type alu_src_t is (reg_a, reg_b, const);
type ddata_src_t is (reg_a, reg_b, const);
type daddr_src_t is (reg_a, reg_b, const);
subtype instr_name_t is string(1 to 12);
type instr_name_array_t is array (0 to 63) of instr_name_t;
subtype opcode_t is unsigned (INST_OPCODE_WIDTH-1 downto 0);
subtype inst_data_t is unsigned (IMEM_ADDR_WIDTH-1 downto 0);
subtype inst_addr_t is unsigned (IMEM_ADDR_WIDTH-1 downto 0);
subtype inst_t is unsigned (IMEM_DATA_WIDTH-1 downto 0);
subtype dmem_data_t is unsigned (DMEM_DATA_WIDTH-1 downto 0);
subtype dmem_addr_t is unsigned (DMEM_DATA_WIDTH-1 downto 0);
subtype reg_ptr_t is unsigned (3 downto 0);
type dmem_array_t is array (natural range <>) of dmem_data_t;
type instr_addr_array is array (integer range <>) of inst_addr_t;
subtype page_sel_t is unsigned (CHIPRAM_SIZE_BITS-DMEM_DATA_WIDTH-2 downto 0);
type alu_op_t is
(
pass_op2,
op1_add_op2,
op1_sub_op2,
op1_addc_op2,
op1_subc_op2,
op1_and_op2,
op1_or_op2,
op1_xor_op2,
swap_op,
shl_op,
shr_op,
rol_op,
ror_op,
rolc_op,
rorc_op
);
type alu_status_t is record
zero : STD_LOGIC;
carry : STD_LOGIC;
end record;
type cpu_status_t is record
alu : alu_status_t;
end record;
type ctrl_lines_t is record
reg_we : STD_LOGIC;
reg_src_sel : reg_src_t;
alu_op1_src_sel : alu_src_t;
alu_op2_src_sel : alu_src_t;
alu_opsel : alu_op_t;
alu_load : STD_LOGIC;
ddata_src_sel : ddata_src_t;
daddr_src_sel : daddr_src_t;
pc_load : STD_LOGIC;
pc_inc : STD_LOGIC;
stk_push : STD_LOGIC;
stk_pop : STD_LOGIC;
stk_pushd : STD_LOGIC;
stk_popd : STD_LOGIC;
mem_access : mem_access_t;
mem_read : STD_LOGIC;
mem_write : STD_LOGIC;
int_exit : STD_LOGIC;
end record;
type dpath_ctrl_out_t is record
lines : ctrl_lines_t;
reg_a_ptr : reg_ptr_t;
reg_b_ptr : reg_ptr_t;
end record;
type int_ctrl_in_t is record
enable : std_logic;
polarity : std_logic;
edge_sens : std_logic;
request : std_logic;
end record;
type creg_ctrl_out_t is record
page_sel : page_sel_t;
int_ctrl : int_ctrl_in_t;
stk_high : unsigned(IMEM_ADDR_WIDTH-DMEM_ADDR_WIDTH-1 downto 0);
cmem_high : unsigned(IMEM_ADDR_WIDTH-DMEM_ADDR_WIDTH-1 downto 0);
end record;
type creg_ctrl_in_t is record
alu : alu_status_t;
end record;
type murom_t is array (0 to integer(2**MUCODE_ADDR_WIDTH)-1) of ctrl_lines_t;
constant instr_name_array : instr_name_array_t :=
(
"NOP ", -- 00
"HALT ", -- 01
"MOV|R|R ", -- 02
"MOV|R|K ", -- 03
"MOVX|R|Ri ", -- 04
"MOVX|R|Ki ", -- 05
"MOVX|Ri|R ", -- 06
"MOVX|Ri|K ", -- 07
"MOVX|Ki|R ", -- 08
"MOVC|R|Ri ", -- 09
"MOVC|R|Ki ", -- 0A
"MOVC|Ri|R ", -- 0B
"MOVC|Ri|K ", -- 0C
"MOVC|Ki|R ", -- 0D
"CMP|R|R ", -- 0E
"CMP|R|K ", -- 0F
"ADD|R|R ", -- 10
"ADD|R|K ", -- 11
"ADDC|R|R ", -- 12
"ADDC|R|K ", -- 13
"SUB|R|R ", -- 14
"SUB|R|K ", -- 15
"SUBC|R|R ", -- 16
"SUBC|R|K ", -- 17
"AND|R|R ", -- 18
"AND|R|K ", -- 19
"OR|R|R ", -- 1A
"OR|R|K ", -- 1B
"XOR|R|R ", -- 1C
"XOR|R|K ", -- 1D
"SHL|R ", -- 1E
"SHR|R ", -- 1F
"ROL|R ", -- 20
"ROR|R ", -- 21
"ROLC|R ", -- 22
"RORC|R ", -- 23
"XOUT|Ki|R ", -- 24
"XOUT|Ri|K ", -- 25
"COUT|Ki|R ", -- 26
"COUT|Ri|K ", -- 27
"XIN|R|Ki ", -- 28
"CIN|R|Ki ", -- 29
"SWAP|R ", -- 2A
"UNDEF ", -- 2B
"UNDEF ", -- 2C
"UNDEF ", -- 2D
"SUB|K|R ", -- 2E
"SUBC|K|R ", -- 2F
"JMP|K ", -- 30
"JZ|K ", -- 31
"JNZ|K ", -- 32
"JC|K ", -- 33
"JNC|K ", -- 34
"JLT|K ", -- 35
"JGT|K ", -- 36
"JLE|K ", -- 37
"JGE|K ", -- 38
"JEQ|K ", -- 39
"JNE|K ", -- 3A
"CALL|K ", -- 3B
"PUSH|R ", -- 3C
"POP|R ", -- 3D
"RET ", -- 3E
"RETI " -- 3F
);
-- Functions
function Instr(opcode : opcode_t) return inst_t;
function Instr(opcode : opcode_t; data : inst_data_t) return inst_t;
function Instr(opcode : opcode_t; data : inst_data_t; reg : integer) return inst_t;
function Instr(opcode : opcode_t; reg_a : integer) return inst_t;
function Instr(opcode : opcode_t; reg_a, reg_b : integer) return inst_t;
function Instr(opcode : opcode_t; reg_a, reg_b, reg_c : integer) return inst_t;
function ctrl_lines_default return ctrl_lines_t;
function idecoder(instr_name : instr_name_t; iphase : iphase_t; alu_status : alu_status_t) return ctrl_lines_t;
function idecoder(opcode : opcode_t; iphase : iphase_t; alu_status : alu_status_t) return ctrl_lines_t;
function gen_murom return murom_t;
function get_muromaddr (opcode : opcode_t; iphase : iphase_t; alu_status : alu_status_t) return unsigned;
function MIN (X, Y: INTEGER) return INTEGER;
function MAX (X, Y: INTEGER) return INTEGER;
end cpu_pkg;
package body cpu_pkg is
function Instr(opcode : opcode_t) return inst_t is
variable inst : inst_t := (others => '0');
begin
inst(inst_t'length-1 downto inst_t'length-opcode_t'length) := opcode;
return inst;
end Instr;
function Instr(opcode : opcode_t; data : inst_data_t) return inst_t is
variable inst : inst_t := (others => '0');
begin
inst(inst_t'length-1 downto inst_t'length-opcode_t'length) := opcode;
inst(inst_t'length-opcode_t'length-1 downto inst_t'length-opcode_t'length-inst_addr_t'length) := data;
return inst;
end Instr;
function Instr(opcode : opcode_t; data : inst_data_t; reg : integer) return inst_t is
variable inst : inst_t := (others => '0');
begin
inst(inst_t'length-1 downto inst_t'length-opcode_t'length) := opcode;
inst(inst_t'length-opcode_t'length-1 downto inst_t'length-opcode_t'length-inst_data_t'length) := data;
inst(reg_ptr_t'length-1 downto 0) := reg_ptr_t(to_unsigned(reg, reg_ptr_t'length));
return inst;
end Instr;
function Instr(opcode : opcode_t; reg_a : integer) return inst_t is
variable inst : inst_t := (others => '0');
begin
inst(inst_t'length-1 downto inst_t'length-opcode_t'length) := opcode;
inst(reg_ptr_t'length-1 downto 0) := reg_ptr_t(to_unsigned(reg_a, reg_ptr_t'length));
return inst;
end Instr;
function Instr(opcode : opcode_t; reg_a, reg_b : integer) return inst_t is
variable inst : inst_t := (others => '0');
begin
inst(inst_t'length-1 downto inst_t'length-opcode_t'length) := opcode;
inst(2*(reg_ptr_t'length)-1 downto reg_ptr_t'length) := reg_ptr_t(to_unsigned(reg_b, reg_ptr_t'length));
inst(reg_ptr_t'length-1 downto 0) := reg_ptr_t(to_unsigned(reg_a, reg_ptr_t'length));
return inst;
end Instr;
function Instr(opcode : opcode_t; reg_a, reg_b, reg_c : integer) return inst_t is
variable inst : inst_t := (others => '0');
begin
inst(inst_t'length-1 downto inst_t'length-opcode_t'length) := opcode;
inst(3*(reg_ptr_t'length)-1 downto 2*reg_ptr_t'length) := reg_ptr_t(to_unsigned(reg_c, reg_ptr_t'length));
inst(2*(reg_ptr_t'length)-1 downto reg_ptr_t'length) := reg_ptr_t(to_unsigned(reg_b, reg_ptr_t'length));
inst(reg_ptr_t'length-1 downto 0) := reg_ptr_t(to_unsigned(reg_a, reg_ptr_t'length));
return inst;
end Instr;
function ctrl_lines_default return ctrl_lines_t is
variable result : ctrl_lines_t;
begin
result.pc_load := '0';
result.pc_inc := '0';
result.stk_push := '0';
result.stk_pop := '0';
result.stk_pushd := '0';
result.stk_popd := '0';
result.reg_we := '0';
result.reg_src_sel := alu_src;
result.ddata_src_sel := reg_a;
result.daddr_src_sel := reg_b;
result.alu_opsel := pass_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.alu_load := '0';
result.mem_access := cmem_access;
result.mem_read := '0';
result.mem_write := '0';
result.int_exit := '0';
return result;
end ctrl_lines_default;
function idecoder(opcode : opcode_t; iphase : iphase_t; alu_status : alu_status_t) return ctrl_lines_t is
variable instr_name : instr_name_t;
begin
instr_name := instr_name_array(to_integer(opcode));
return idecoder(instr_name, iphase, alu_status);
end idecoder;
function idecoder(instr_name : instr_name_t; iphase : iphase_t; alu_status : alu_status_t) return ctrl_lines_t is
variable result : ctrl_lines_t;
variable ze, cy : STD_LOGIC;
begin
ze := alu_status.zero;
cy := alu_status.carry;
result := ctrl_lines_default;
if iphase = 0 then
result.pc_inc := '1';
end if;
case instr_name is
when "HALT " =>
result.pc_inc := '0';
when "MOV|R|R " => -- R(a) <= R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := pass_op2;
result.alu_op2_src_sel := reg_b;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "MOV|R|K " => -- R(a) <= #kk
result.reg_src_sel := alu_src;
result.alu_opsel := pass_op2;
result.alu_op2_src_sel := const;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "MOVC|Ri|R " => -- [R(b)] <= R(a)
result.mem_access := cmem_access;
result.daddr_src_sel := reg_b;
result.ddata_src_sel := reg_a;
if iphase = 0 then
result.mem_write := '1';
end if;
when "MOVC|Ri|K " => -- [R(a)] <= kk
result.mem_access := cmem_access;
result.daddr_src_sel := reg_a;
result.ddata_src_sel := const;
if iphase = 0 then
result.mem_write := '1';
end if;
when "COUT|Ri|K " => -- [R(a)] <= kk
result.mem_access := cio_access;
result.daddr_src_sel := reg_a;
result.ddata_src_sel := const;
if iphase = 0 then
result.mem_write := '1';
end if;
when "MOVC|R|Ri " => -- R(a) <= [R(b)]
result.mem_access := cmem_access;
result.reg_src_sel := cmem_src;
result.daddr_src_sel := reg_b;
if iphase = 1 then
result.reg_we := '1';
end if;
when "MOVC|R|Ki " => -- R(a) <= [#addr]
result.mem_access := cmem_access;
result.reg_src_sel := cmem_src;
result.daddr_src_sel := const;
if iphase = 1 then
result.reg_we := '1';
end if;
when "CIN|R|Ki " => -- R(a) <= [#addr]
result.mem_access := cio_access;
result.reg_src_sel := cmem_src;
result.daddr_src_sel := const;
if iphase = 1 then
result.reg_we := '1';
end if;
when "MOVC|Ki|R " => -- [#addr] <= R(a)
result.mem_access := cmem_access;
result.daddr_src_sel := const;
result.ddata_src_sel := reg_a;
if iphase = 0 then
result.mem_write := '1';
end if;
when "COUT|Ki|R " => -- [#addr] <= R(a)
result.mem_access := cio_access;
result.daddr_src_sel := const;
result.ddata_src_sel := reg_a;
if iphase = 0 then
result.mem_write := '1';
end if;
when "MOVX|Ri|R " => -- [R(b)] <= R(a)
result.mem_access := xmem_access;
result.daddr_src_sel := reg_b;
result.ddata_src_sel := reg_a;
if iphase = 0 then
result.mem_write := '1';
end if;
when "MOVX|Ri|K " => -- [R(a)] <= kk
result.mem_access := xmem_access;
result.daddr_src_sel := reg_a;
result.ddata_src_sel := const;
if iphase = 0 then
result.mem_write := '1';
end if;
when "XOUT|Ri|K " => -- [R(a)] <= kk
result.mem_access := xio_access;
result.daddr_src_sel := reg_a;
result.ddata_src_sel := const;
if iphase = 0 then
result.mem_write := '1';
end if;
when "MOVX|R|Ri " => -- R(a) <= [R(b)]
result.mem_access := xmem_access;
result.reg_src_sel := xmem_src;
result.daddr_src_sel := reg_b;
if iphase = 0 then
result.mem_read := '1';
elsif iphase = 1 then
result.reg_we := '1';
end if;
when "MOVX|R|Ki " => -- R(a) <= [#addr]
result.mem_access := xmem_access;
result.reg_src_sel := xmem_src;
result.daddr_src_sel := const;
if iphase = 0 then
result.mem_read := '1';
elsif iphase = 1 then
result.reg_we := '1';
end if;
when "XIN|R|Ki " => -- R(a) <= [#addr]
result.mem_access := xio_access;
result.reg_src_sel := xmem_src;
result.daddr_src_sel := const;
if iphase = 0 then
result.mem_read := '1';
elsif iphase = 1 then
result.reg_we := '1';
end if;
when "MOVX|Ki|R " => -- [#addr] <= R(a)
result.mem_access := xmem_access;
result.daddr_src_sel := const;
result.ddata_src_sel := reg_a;
if iphase = 0 then
result.mem_write := '1';
end if;
when "XOUT|Ki|R " => -- [#addr] <= R(a)
result.mem_access := xio_access;
result.daddr_src_sel := const;
result.ddata_src_sel := reg_a;
if iphase = 0 then
result.mem_write := '1';
end if;
when "ADD|R|R " => -- R(a) <= R(a) + R(b)
result.alu_opsel := op1_add_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "ADD|R|K " => -- R(a) <= R(a) + k
result.alu_opsel := op1_add_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "ADDC|R|R " => -- R(a) <= R(a) + R(b)
result.alu_opsel := op1_addc_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "ADDC|R|K " => -- R(a) <= R(a) + k
result.alu_opsel := op1_addc_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SUB|R|R " => -- R(a) <= R(a) + R(b)
result.alu_opsel := op1_sub_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SUB|R|K " => -- R(a) <= R(a) + k
result.alu_opsel := op1_sub_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SUB|K|R " => -- R(a) <= k - R(a)
result.alu_opsel := op1_sub_op2;
result.alu_op1_src_sel := const;
result.alu_op2_src_sel := reg_a;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SUBC|R|R " => -- R(a) <= R(a) + R(b)
result.alu_opsel := op1_subc_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SUBC|R|K " => -- R(a) <= R(a) + k
result.alu_opsel := op1_subc_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SUBC|K|R " => -- R(a) <= K - R(a)
result.alu_opsel := op1_subc_op2;
result.alu_op1_src_sel := const;
result.alu_op2_src_sel := reg_a;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "AND|R|R " => -- R(a) <= R(a) and R(b)
result.alu_opsel := op1_and_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "AND|R|K " => -- R(a) <= R(a) and k
result.alu_opsel := op1_and_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "OR|R|R " => -- R(a) <= R(a) or R(b)
result.alu_opsel := op1_or_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "OR|R|K " => -- R(a) <= R(a) or R(b)
result.alu_opsel := op1_or_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "XOR|R|R " => -- R(a) <= R(a) xor R(b)
result.alu_opsel := op1_xor_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "XOR|R|K " => -- R(a) <= R(a) xor R(b)
result.alu_opsel := op1_xor_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.reg_src_sel := alu_src;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SWAP|R " => -- R(a) <= R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := swap_op;
result.alu_op1_src_sel := reg_a;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SHL|R " => -- R(a) <= R(a) xor R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := shl_op;
result.alu_op1_src_sel := reg_a;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "SHR|R " => -- R(a) <= R(a) xor R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := shr_op;
result.alu_op1_src_sel := reg_a;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "ROL|R " => -- R(a) <= R(a) xor R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := rol_op;
result.alu_op1_src_sel := reg_a;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "ROR|R " => -- R(a) <= R(a) xor R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := ror_op;
result.alu_op1_src_sel := reg_a;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "ROLC|R " => -- R(a) <= R(a) xor R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := rolc_op;
result.alu_op1_src_sel := reg_a;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "RORC|R " => -- R(a) <= R(a) xor R(b)
result.reg_src_sel := alu_src;
result.alu_opsel := rorc_op;
result.alu_op1_src_sel := reg_a;
result.alu_load := '1';
if iphase = 1 then
result.reg_we := '1';
end if;
when "CMP|R|R " => --
result.alu_opsel := op1_sub_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := reg_b;
result.alu_load := '1';
when "CMP|R|K " => --
result.alu_opsel := op1_sub_op2;
result.alu_op1_src_sel := reg_a;
result.alu_op2_src_sel := const;
result.alu_load := '1';
when "JMP|K " => -- PC <= #addr
if iphase = 0 then
result.pc_load := '1';
end if;
when "JZ|K " => -- PC <= #addr, zero
if iphase = 0 then
if ze = '1' then
result.pc_load := '1';
end if;
end if;
when "JNZ|K " => -- PC <= #addr, !zero
if iphase = 0 then
if ze = '0' then
result.pc_load := '1';
end if;
end if;
when "JC|K " => -- PC <= #addr, carry
if iphase = 0 then
if cy = '1' then
result.pc_load := '1';
end if;
end if;
when "JNC|K " => -- PC <= #addr, !carry
if iphase = 0 then
if cy = '0' then
result.pc_load := '1';
end if;
end if;
when "JLT|K " => -- PC <= #addr, !carry
if iphase = 0 then
if cy = '1' then
result.pc_load := '1';
end if;
end if;
when "JGT|K " => --
if iphase = 0 then
if (cy or ze) = '0' then
result.pc_load := '1';
end if;
end if;
when "JLE|K " => --
if iphase = 0 then
if (cy xor ze) = '1' then
result.pc_load := '1';
end if;
end if;
when "JGE|K " => --
if iphase = 0 then
if (not cy or ze) = '1' then
result.pc_load := '1';
end if;
end if;
when "JEQ|K " => --
if iphase = 0 then
if ze = '1' then
result.pc_load := '1';
end if;
end if;
when "JNE|K " => --
if iphase = 0 then
if ze = '0' then
result.pc_load := '1';
end if;
end if;
when "PUSH|R " => -- push
if iphase = 0 then
result.stk_pushd := '1';
end if;
when "POP|R " => -- pop
result.reg_src_sel := stk_src;
if iphase = 0 then
result.stk_popd := '1';
elsif iphase = 1 then
result.reg_we := '1';
end if;
when "CALL|K " => -- call
if iphase = 0 then
result.pc_load := '1';
result.stk_push := '1';
end if;
when "RET " => -- return
if iphase = 0 then
result.pc_load := '1';
result.stk_pop := '1';
end if;
when "RETI " => -- return
result.pc_inc := '0';
result.int_exit := '1';
when others => null; -- nop
end case;
return result;
end idecoder;
function gen_murom return murom_t is
variable result : murom_t;
variable opcode : opcode_t;
variable iphase : iphase_t;
variable addr : unsigned(MUCODE_ADDR_WIDTH-1 downto 0);
variable alu_status : alu_status_t;
variable pos : integer := 0;
begin
for i in 0 to 2**addr'length-1 loop
addr := to_unsigned(i, addr'length);
opcode := addr(opcode'length-1 downto 0);
pos := opcode'length;
iphase := 0;
if addr(pos) = '1' then
iphase := 1;
end if;
pos := pos + 1;
alu_status.zero := addr(pos);
pos := pos + 1;
alu_status.carry := addr(pos);
result(i) := idecoder(opcode, iphase, alu_status);
end loop;
return result;
end gen_murom;
function get_muromaddr (opcode : opcode_t; iphase : iphase_t; alu_status : alu_status_t) return unsigned is
variable addr : unsigned(MUCODE_ADDR_WIDTH-1 downto 0);
begin
addr := alu_status.carry & alu_status.zero & to_unsigned(iphase, 1) & opcode;
return addr;
end get_muromaddr;
-------------------------------------------------------------
function MIN (X, Y: INTEGER) return INTEGER is
variable res : integer := X;
begin
if Y < X then
res := Y;
end if;
return res;
end MIN;
-------------------------------------------------------------
function MAX (X, Y: INTEGER) return INTEGER is
variable res : integer := X;
begin
if Y > X then
res := Y;
end if;
return res;
end MAX;
end cpu_pkg;