[rtl] improve CPU front end (#777)

stnolting · Jan 27, 2024 · 4b46f13 · 4b46f13
2 parents 34c712a + 36a88e8
commit 4b46f13
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -30,6 +30,7 @@ mimpid = 0x01040312 -> Version 01.04.03.12 -> v1.4.3.12
 
 | Date | Version | Comment | Link |
 |:----:|:-------:|:--------|:----:|
+| 27.01.2024 | 1.9.3.6 | improve CPU's front end (instruction fetch) increasing overall performance | [#777](https://github.com/stnolting/neorv32/pull/777) |
 | 27.01.2024 | 1.9.3.5 | :bug: fix typo that renders the clock gating (added in v1.9.3.4) useless: CPU sleep output stuck at zero | [#776](https://github.com/stnolting/neorv32/pull/776) |
 | 24.01.2024 | 1.9.3.4 | :sparkles: add optional CPU clock gating (via new generic `CLOCK_GATING_EN`): shut down the CPU clock during sleep mode; :warning: add new HDL design file for the clock gate (`neorv32_clockgate.vhd`) | [#775](https://github.com/stnolting/neorv32/pull/775) |
 | 23.01.2024 | 1.9.3.3 | :bug: remove compressed floating point load/store operations as they are **not** supported by `Zfinx` | [#](https://github.com/stnolting/neorv32/pull/771) |

diff --git a/rtl/core/neorv32_cpu_control.vhd b/rtl/core/neorv32_cpu_control.vhd
@@ -383,6 +383,8 @@ begin
         -- ------------------------------------------------------------
           if (ipb.free = "11") then -- wait for free IPB space
             fetch_engine.state <= IF_PENDING;
+          elsif (fetch_engine.restart = '1') or (fetch_engine.reset = '1') then -- restart request due to branch
+            fetch_engine.state <= IF_RESTART;
           end if;
 
         when IF_PENDING => -- wait for bus response and write instruction data to prefetch buffer

diff --git a/rtl/core/neorv32_package.vhd b/rtl/core/neorv32_package.vhd
@@ -56,7 +56,7 @@ package neorv32_package is
 
   -- Architecture Constants -----------------------------------------------------------------
   -- -------------------------------------------------------------------------------------------
-  constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01090305"; -- hardware version
+  constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01090306"; -- hardware version
   constant archid_c     : natural := 19; -- official RISC-V architecture ID
   constant XLEN         : natural := 32; -- native data path width