cve2/ibex_core.core
Greg Chadwick 89e5fc11ed [RTL] Add configurable third pipeline stage
The third pipeline stage is a new writeback stage. Ibex can now be
configured as the original two stage design or the new three stage
design using the `WritebackStage` parameter in ibex_core. This defaults
to 0 (giving the original two stage design).

The three stage design is *EXPERIMENTAL*

In the three stage design all register write back occurs in the third,
final stage. This allows a cycle for responses to loads and stores so
when the memory system can respond in a single cycle there will be no
stall. This offers significant performance benefits.

Documentation of the three stage design is still to be written so
existing documentation applies to the two stage design only as various
aspects of Ibex behaviour will change in the three stage design.

Signed-off-by: Greg Chadwick <gac@lowrisc.org>
2020-03-06 15:29:14 +00:00

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CAPI=2:
# Copyright lowRISC contributors.
# Licensed under the Apache License, Version 2.0, see LICENSE for details.
# SPDX-License-Identifier: Apache-2.0
name: "lowrisc:ibex:ibex_core:0.1"
description: "CPU core with 2 stage pipeline implementing the RV32IMC_Zicsr ISA"
filesets:
files_rtl:
depend:
- lowrisc:prim:assert
files:
- rtl/ibex_pkg.sv
- rtl/ibex_alu.sv
- rtl/ibex_compressed_decoder.sv
- rtl/ibex_controller.sv
- rtl/ibex_cs_registers.sv
- rtl/ibex_counters.sv
- rtl/ibex_decoder.sv
- rtl/ibex_ex_block.sv
- rtl/ibex_fetch_fifo.sv
- rtl/ibex_id_stage.sv
- rtl/ibex_if_stage.sv
- rtl/ibex_load_store_unit.sv
- rtl/ibex_multdiv_fast.sv
- rtl/ibex_multdiv_slow.sv
- rtl/ibex_prefetch_buffer.sv
- rtl/ibex_pmp.sv
- rtl/ibex_wb_stage.sv
# XXX: Figure out the best way to switch these two implementations
# dynamically on the target.
# - rtl/ibex_register_file_latch.sv # ASIC
# - rtl/ibex_register_file_fpga.sv # FPGA
- rtl/ibex_register_file_ff.sv # generic FF-based
- rtl/ibex_core.sv
file_type: systemVerilogSource
files_lint:
depend:
- lowrisc:ibex:sim_shared
files_lint_verilator:
files:
- lint/verilator_waiver.vlt: {file_type: vlt}
files_check_tool_requirements:
depend:
- lowrisc:ibex:check_tool_requirements
parameters:
RVFI:
datatype: bool
paramtype: vlogdefine
SYNTHESIS:
datatype: bool
paramtype: vlogdefine
RV32E:
datatype: bool
paramtype: vlogparam
RV32M:
datatype: bool
paramtype: vlogparam
MultiplierImplementation:
datatype: str
paramtype: vlogparam
description: "Multiplier implementation. Valid values: fast, slow"
default: fast
BranchTargetALU:
datatype: int
paramtype: vlogparam
default: 0
description: "Enables seperate branch target ALU (increasing branch performance EXPERIMENTAL) [0/1]"
WritebackStage:
datatype: int
paramtype: vlogparam
default: 0
description: "Enables third pipeline stage (EXPERIMENTAL) [0/1]"
targets:
default:
filesets:
- tool_verilator ? (files_lint_verilator)
- files_rtl
- files_check_tool_requirements
lint:
filesets:
- tool_verilator ? (files_lint_verilator)
- files_rtl
- files_lint
- files_check_tool_requirements
parameters:
- SYNTHESIS=true
- RVFI=true
default_tool: verilator
toplevel: ibex_core
tools:
verilator:
mode: lint-only
verilator_options:
- "-Wall"