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B extension: Correct doc and parameter usage

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Signed-off-by: Pirmin Vogel <vogelpi@lowrisc.org>
This commit is contained in:
Pirmin Vogel 2020-08-20 09:57:56 +02:00
parent 8364e356c2
commit 4127a5464b
11 changed files with 19 additions and 25 deletions
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5
doc/instruction_decode_execute.rst
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@ -67,10 +67,13 @@ Other blocks use the ALU for the following tasks:
Bit Manipulation Extension
Support for the `RISC-V Bit Manipulation Extension (draft version 0.92 from November 8, 2019) <https://github.com/riscv/riscv-bitmanip/blob/master/bitmanip-0.92.pdf>`_ is optional. [#B_draft]_
It can be enabled via the enumerated parameter ``RV32B`` defined in :file:`rtl/ibex_pkg.sv`.
By default, this parameter is set to "ibex_pkg::RV32BNone" to disable the bit manipulation extension.
There are two versions of the bit manipulation extension available:
The balanced implementation comprises a set of sub-extensions aiming for good benefits at a reasonable area overhead.
It can be selected by setting the ``RV32B`` parameter to "ibex_pkg::RV32BBalanced".
The full implementation comprises all 32 bit instructions defined in the extension.
This version can be selected by setting the ``RV32B`` parameter to "ibex_pkg::RV32BFull".
The following table lists the implemented instructions in each version.
Multi-cycle instructions are completed in 2 cycles.
All remaining instructions complete in a single cycle.
@ -84,7 +87,7 @@ Bit Manipulation Extension
+---------------------------------+---------------+--------------------------+
| Zbp (Permutation) | Full | None |
+---------------------------------+---------------+--------------------------+
| Zbp (Bit extract/deposit) | Full | All |
| Zbe (Bit extract/deposit) | Full | All |
+---------------------------------+---------------+--------------------------+
| Zbf (Bit-field place) | Balanced/Full | All |
+---------------------------------+---------------+--------------------------+

9
doc/integration.rst
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@ -93,11 +93,10 @@ Parameters
+------------------------------+-------------------+------------+-----------------------------------------------------------------+
| ``RV32M`` | bit | 1 | M(ultiply) extension enable |
+------------------------------+-------------------+------------+-----------------------------------------------------------------+
| ``RV32B`` | ibex_pkg::rv32b_e | RV32BNone | *EXPERIMENTAL* - B(itmanipulation) extension select: |
| | | | "RV32BNone": No B-extension |
| | | | "RV32BBalanced": Sub-extensions Zbb, Zbs, Zbf and |
| | | | Zbt |
| | | | "RV32Full": All sub-extensions |
| ``RV32B`` | ibex_pkg::rv32b_e | RV32BNone | B(itmanipulation) extension select: |
| | | | "ibex_pkg::RV32BNone": No B-extension |
| | | | "ibex_pkg::RV32BBalanced": Sub-extensions Zbb, Zbs, Zbf and Zbt |
| | | | "ibex_pkg::RV32Full": All sub-extensions |
+------------------------------+-------------------+------------+-----------------------------------------------------------------+
| ``BranchTargetALU`` | bit | 0 | *EXPERIMENTAL* - Enables branch target ALU removing a stall |
| | | | cycle from taken branches |

2
dv/riscv_compliance/ibex_riscv_compliance.core
View file

@ -40,7 +40,7 @@ parameters:
datatype: str
default: ibex_pkg::RV32BNone
paramtype: vlogdefine
description: "Bitmanip implementation parameter enum. See ibex_pkg.sv (EXPERIMENTAL)"
description: "Bitmanip implementation parameter enum. See the ibex_pkg::rv32b_e enum in ibex_pkg.sv for permitted values."
MultiplierImplementation:
datatype: str

2
dv/riscv_compliance/rtl/ibex_riscv_compliance.sv
View file

@ -20,7 +20,7 @@ module ibex_riscv_compliance (
parameter int unsigned PMPNumRegions = 4;
parameter bit RV32E = 1'b0;
parameter bit RV32M = 1'b1;
parameter bit RV32B = 1'b0;
parameter ibex_pkg::rv32b_e RV32B = ibex_pkg::RV32BNone;
parameter MultiplierImplementation = "fast";
parameter bit BranchTargetALU = 1'b0;
parameter bit WritebackStage = 1'b0;

2
examples/simple_system/ibex_simple_system.core
View file

@ -39,7 +39,7 @@ parameters:
datatype: str
default: ibex_pkg::RV32BNone
paramtype: vlogdefine
description: "Bitmanip implementation parameter enum. See ibex_pkg.sv (EXPERIMENTAL)"
description: "Bitmanip implementation parameter enum. See the ibex_pkg::rv32b_e enum in ibex_pkg.sv for permitted values."
SRAMInitFile:
datatype: str

2
ibex_core.core
View file

@ -80,7 +80,7 @@ parameters:
datatype: str
default: ibex_pkg::RV32BNone
paramtype: vlogdefine
description: "Bitmanip implementation parameter enum. See ibex_pkg.sv (EXPERIMENTAL)"
description: "Bitmanip implementation parameter enum. See the ibex_pkg::rv32b_e enum in ibex_pkg.sv for permitted values."
MultiplierImplementation:
datatype: str

2
ibex_core_tracing.core
View file

@ -38,7 +38,7 @@ parameters:
datatype: str
default: ibex_pkg::RV32BNone
paramtype: vlogdefine
description: "Bitmanip implementation parameter enum. See ibex_pkg.sv (EXPERIMENTAL)"
description: "Bitmanip implementation parameter enum. See the ibex_pkg::rv32b_e enum in ibex_pkg.sv for permitted values."
MultiplierImplementation:
datatype: str

6
rtl/ibex_core.sv
View file

@ -9,10 +9,6 @@
`include "prim_assert.sv"
`ifndef RV32B
`define RV32B ibex_pkg::RV32BNone
`endif
/**
* Top level module of the ibex RISC-V core
*/
@ -24,7 +20,7 @@ module ibex_core #(
parameter int unsigned MHPMCounterWidth = 40,
parameter bit RV32E = 1'b0,
parameter bit RV32M = 1'b1,
parameter ibex_pkg::rv32b_e RV32B = `RV32B,
parameter ibex_pkg::rv32b_e RV32B = ibex_pkg::RV32BNone,
parameter bit BranchTargetALU = 1'b0,
parameter bit WritebackStage = 1'b0,
parameter MultiplierImplementation = "fast",

6
rtl/ibex_core_tracing.sv
View file

@ -2,10 +2,6 @@
// Licensed under the Apache License, Version 2.0, see LICENSE for details.
// SPDX-License-Identifier: Apache-2.0
`ifndef RV32B
`define RV32B ibex_pkg::RV32BNone
`endif
/**
* Top level module of the ibex RISC-V core with tracing enabled
*/
@ -18,7 +14,7 @@ module ibex_core_tracing #(
parameter int unsigned MHPMCounterWidth = 40,
parameter bit RV32E = 1'b0,
parameter bit RV32M = 1'b1,
parameter ibex_pkg::rv32b_e RV32B = `RV32B,
parameter ibex_pkg::rv32b_e RV32B = ibex_pkg::RV32BNone,
parameter bit BranchTargetALU = 1'b0,
parameter bit WritebackStage = 1'b0,
parameter MultiplierImplementation = "fast",

6
rtl/ibex_pkg.sv
View file

@ -13,9 +13,9 @@ package ibex_pkg;
/////////////////////////
typedef enum integer {
RV32BNone,
RV32BBalanced,
RV32BFull
RV32BNone = 0,
RV32BBalanced = 1,
RV32BFull = 2
} rv32b_e;
/////////////

2
syn/tcl/lr_synth_flow_var_setup.tcl
View file

@ -15,7 +15,7 @@ set_flow_bool_var flatten 1 "flatten"
set_flow_bool_var timing_run 0 "timing run"
set_flow_bool_var ibex_branch_target_alu 0 "Enable branch target ALU in Ibex"
set_flow_bool_var ibex_writeback_stage 0 "Enable writeback stage in Ibex"
set_flow_var ibex_bitmanip 0 "Bitmanip extenion setting for Ibex (0,1,2 - enums not supported)"
set_flow_var ibex_bitmanip 0 "Bitmanip extenion setting for Ibex (see ibex_pkg::rv32b_e for permitted values. Enum names are not supported in Yosys.)"
set_flow_var ibex_multiplier "fast" "Multiplier implementation for Ibex (slow/fast/single-cycle)"
source $lr_synth_config_file