//============================================================================
|
//============================================================================
|
// BRANCH.v
|
// BRANCH.v
|
// Jcc disp8
|
// Jcc disp8
|
// - conditional branches
|
// - conditional branches
|
// - fetch an 8 bit displacement and add into IP
|
// - fetch an 8 bit displacement and add into IP
|
//
|
//
|
//
|
//
|
// (C) 2009-2012 Robert Finch
|
// (C) 2009-2012 Robert Finch
|
// Stratford
|
// Stratford
|
// robfinch<remove>@opencores.org
|
// robfinch<remove>@finitron.ca
|
//
|
//
|
//
|
//
|
// This source file is free software: you can redistribute it and/or modify
|
// This source file is free software: you can redistribute it and/or modify
|
// it under the terms of the GNU Lesser General Public License as published
|
// it under the terms of the GNU Lesser General Public License as published
|
// by the Free Software Foundation, either version 3 of the License, or
|
// by the Free Software Foundation, either version 3 of the License, or
|
// (at your option) any later version.
|
// (at your option) any later version.
|
//
|
//
|
// This source file is distributed in the hope that it will be useful,
|
// This source file is distributed in the hope that it will be useful,
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
// GNU General Public License for more details.
|
// GNU General Public License for more details.
|
//
|
//
|
// You should have received a copy of the GNU General Public License
|
// You should have received a copy of the GNU General Public License
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
//
|
//
|
//
|
//
|
//=============================================================================
|
//=============================================================================
|
//
|
//
|
// Fetch branch displacement if taking branch, otherwise skip
|
// Fetch branch displacement if taking branch, otherwise skip
|
//
|
//
|
BRANCH1:
|
BRANCH1:
|
if (take_br) begin
|
if (take_br) begin
|
`INITIATE_CODE_READ
|
code_read();
|
state <= BRANCH2;
|
state <= BRANCH2;
|
end
|
end
|
else begin
|
else begin
|
ip <= ip_inc;
|
ip <= ip_inc;
|
state <= IFETCH;
|
state <= IFETCH;
|
end
|
end
|
BRANCH2:
|
BRANCH2:
|
if (ack_i) begin
|
if (ack_i) begin
|
`TERMINATE_CODE_READ
|
term_code_read();
|
disp16 <= {{8{dat_i[7]}},dat_i};
|
disp16 <= {{8{dat_i[7]}},dat_i};
|
state <= BRANCH3;
|
state <= BRANCH3;
|
end
|
end
|
BRANCH3:
|
BRANCH3:
|
begin
|
begin
|
ip <= ip + disp16;
|
ip <= ip + disp16;
|
state <= IFETCH;
|
state <= IFETCH;
|
end
|
end
|
|
|
