+-- `Deep Thought', a softcore CPU implemented on a FPGA
+--
+-- Copyright (C) 2010 Markus Hofstaetter <markus.manrow@gmx.at>
+-- Copyright (C) 2010 Martin Perner <e0725782@student.tuwien.ac.at>
+-- Copyright (C) 2010 Stefan Rebernig <stefan.rebernig@gmail.com>
+-- Copyright (C) 2010 Manfred Schwarz <e0725898@student.tuwien.ac.at>
+-- Copyright (C) 2010 Bernhard Urban <lewurm@gmail.com>
+--
+-- 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/>.
+
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
instr_s.reg_dest_addr := instruction(22 downto 19);
instr_s.op_group := STACK_OP;
instr_s.op_detail(NO_PSW_OPT) := '1';
+ instr_s.op_detail(PWREN_OPT) := '1';
case instruction(18 downto 17) is
- when "00" =>
+ when "00" => --pop
instr_s.op_detail(PUSH_OPT) := '0';
- when "01" => null;
+ when "01" => --disc
+ instr_s.op_detail(PUSH_OPT) := '0';
+ instr_s.op_detail(NO_DST_OPT) := '1';
- when "10" => null;
+ when "10" => --fetch
+ instr_s.op_detail(PUSH_OPT) := '0';
+ instr_s.op_detail(PWREN_OPT) := '0';
- when "11" =>
+ when "11" => --push
instr_s.op_detail(PUSH_OPT) := '1';
when others => null;
instr_s.immediate(31 downto 16) := (others => '1');
end if;
- if (instr_s.jmptype = "00") then
--- instr_s.op_detail(SUB_OPT) := not instr_s.opcode(0);
- instr_s.op_group := JMP_OP;
- end if;
+ case instr_s.jmptype is
+ when "00" =>
+ instr_s.op_group := JMP_OP;
+
+ when "01" =>
+ instr_s.op_group := JMP_ST_OP;
+
+ when "10" =>
+ instr_s.op_group := JMP_ST_OP;
+ instr_s.op_detail(RET_OPT) := '1';
+
+ when "11" =>
+ instr_s.op_group := JMP_OP;
+ instr_s.op_detail(JMP_REG_OPT) := '1';
+ instr_s.op_detail(IMM_OPT) := '1';
+ instr_s.immediate := (others => '0');
+
+ when others => null;
+ end case;
- if (instr_s.jmptype = "01") then
- instr_s.op_group := JMP_ST_OP;
- -- instr_s.op_detail(RET_OPT) := '0';
- end if;
-
- if (instr_s.jmptype = "10") then
- instr_s.op_group := JMP_ST_OP;
- instr_s.op_detail(RET_OPT) := '1';
- end if;
+-- if (instr_s.jmptype = "00") then
+---- instr_s.op_detail(SUB_OPT) := not instr_s.opcode(0);
+-- instr_s.op_group := JMP_OP;
+-- end if;
+--
+-- if (instr_s.jmptype = "01") then
+-- instr_s.op_group := JMP_ST_OP;
+-- -- instr_s.op_detail(RET_OPT) := '0';
+-- end if;
+--
+-- if (instr_s.jmptype = "10") then
+-- instr_s.op_group := JMP_ST_OP;
+-- instr_s.op_detail(RET_OPT) := '1';
+-- end if;
+--
+-- if (instr_s.jmptype = "11") then
+-- instr_s.op_group := JMP_OP;
+-- instr_s.op_detail(JMP_REG_OPT) := '1';
+-- instr_s.op_detail(IMM_OPT) := '1';
+-- instr_s.immediate := (others => '0');
+-- end if;
if (instr_s.predicates = "1111" or instr_s.jmptype = "10") then
instr_s.bp := '0';