🐛 fixed bug in debugger park loop

missing fence.i isntruction to resync with DM's program buffer if i-cache is implemented
stnolting · Jun 21, 2021 · 35e3d53 · 35e3d53
1 parent 997f91b
commit 35e3d53
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Showing 4 changed files with 5 additions and 2 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -24,6 +24,7 @@ defined by the `hw_version_c` constant in the main VHDL package file [`rtl/core/
 
 | Date (*dd.mm.yyyy*) | Version | Comment |
 |:----------:|:-------:|:--------|
+| 21.06.2021 | 1.5.6.14 | :bug: fixed bug in debugger "park loop": `fence.i` instruction was missing before executing the DM's program buffer - this caused execution of outdated instructions from the program buffer if the **instruction cache** is implemented |
 | 21.06.2021 | 1.5.6.13 | removed `TINY_SHIFT_EN` generic; clean-up of CPU co-processor system: removed "dummy co-processor" for CSR read access, moved CPU shifter core into new co-processor; simplified default (bit-serial) shifter logic (single bit-shifts only) and multi-cycl instructions decode logic |
 | 18.06.2021 | 1.5.6.12 | clean-up of CPU co-processor system (removed unused co-processor slots 4,5,6,7) |
 | 15.06.2021 | 1.5.6.11 | made bootloader more configuration-independent: bootloader now only uses the first 512 bytes of internal/external DMEM for runtime data - hence, the DMEM size is not further relevant as long as it greater than or equal to 512 bytes |

diff --git a/rtl/core/neorv32_debug_dm.vhd b/rtl/core/neorv32_debug_dm.vhd
@@ -214,7 +214,8 @@ architecture neorv32_debug_dm_rtl of neorv32_debug_dm is
     00000020 => x"01000413",
     00000021 => x"98802023",
     00000022 => x"7b202473",
-    00000023 => x"88000067",
+    00000023 => x"0000100f",
+    00000024 => x"88000067",
     others   => x"00100073"  -- ebreak
   );
 

diff --git a/rtl/core/neorv32_package.vhd b/rtl/core/neorv32_package.vhd
@@ -70,7 +70,7 @@ package neorv32_package is
   -- Architecture Constants (do not modify!) ------------------------------------------------
   -- -------------------------------------------------------------------------------------------
   constant data_width_c   : natural := 32; -- native data path width - do not change!
-  constant hw_version_c   : std_ulogic_vector(31 downto 0) := x"01050613"; -- no touchy!
+  constant hw_version_c   : std_ulogic_vector(31 downto 0) := x"01050614"; -- no touchy!
   constant archid_c       : natural := 19; -- official NEORV32 architecture ID - hands off!
   constant rf_r0_is_reg_c : boolean := true; -- x0 is a *physical register* that has to be initialized to zero by the CPU
 

diff --git a/sw/ocd-firmware/park_loop.S b/sw/ocd-firmware/park_loop.S
@@ -99,4 +99,5 @@ execute_progbuf:
     addi   s0, zero, SREG_EXECUTE_ACK
     sw     s0, DBMEM_SREG_BASE(zero)        // ACK that execution is about to start
     csrr   s0, dscratch0                    // restore s0 from dscratch0
+    fence.i                                 // synchronize i-cache & prefetch with memory (program buffer)
     jalr   zero, zero, %lo(DBMEM_PBUF_BASE) // jump to beginning of program buffer