Fix for issue stnolting#782

Added a illegal instruction exception to the register to register branch of the compressed instruction decoder. Signed-off-by: Mikael Mortensen <119539842+mikaelsky@users.noreply.github.com>
mikaelsky · Jan 31, 2024 · 7222b78 · 7222b78
1 parent 8e52234
commit 7222b78
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/rtl/core/neorv32_cpu_decompressor.vhd b/rtl/core/neorv32_cpu_decompressor.vhd
@@ -317,6 +317,9 @@ begin
                     decoded(instr_funct3_msb_c downto instr_funct3_lsb_c) <= funct3_and_c;
                     decoded(instr_funct7_msb_c downto instr_funct7_lsb_c) <= "0000000";
                 end case;
+                if (ci_instr16_i(12) = '1') then -- reserved instruction space.
+                  illegal <= '1';
+                end if;
             end case;
 
         end case;