🐛 [rtl] fix bug in co-processor monitor

CHANGELOG.md

@@ -31,8 +31,9 @@ mimpid = 0x01040312 => Version 01.04.03.12 => v1.4.3.12
 
 | Date (*dd.mm.yyyy*) | Version | Comment |
 |:-------------------:|:-------:|:--------|
+| 18.02.2023 | 1.8.0.8 | :bug: fix minor bug in CPU's co-processor monitor; minor VHDL clean-ups and edits; [#500](https://github.com/stnolting/neorv32/pull/500) |
 | 13.02.2023 | 1.8.0.7 | minor CPU optimization and fixes; [#497](https://github.com/stnolting/neorv32/pull/497) |
-| 11.02.2023 | 1.8.0.6 | :warning: replaced boolean `IO_GPIO_EN` generic by natural `IO_GPIO_NUM` generic to fine-tune GPIO pin number; [#491](https://github.com/stnolting/neorv32/pull/491) |
+| 11.02.2023 | 1.8.0.6 | :warning: replace boolean `IO_GPIO_EN` generic by natural `IO_GPIO_NUM` generic to fine-tune GPIO pin number; [#491](https://github.com/stnolting/neorv32/pull/491) |
 | 10.02.2023 | 1.8.0.5 | :test_tube: add CPU co-processor monitor (to auto-terminate operation if a co-processor operation takes too long); [#490](https://github.com/stnolting/neorv32/pull/490) |
 | 10.02.2023 | 1.8.0.4 | replace CPU-internal control bus by a VHDL `record` (much cleaner code); minor control optimizations; add 6ht CPU co-processor slot (yet unused); [#489](https://github.com/stnolting/neorv32/pull/489) |
 | 05.02.2023 | 1.8.0.3 | CPU control optimizations; [#487](https://github.com/stnolting/neorv32/pull/487) |

rtl/core/neorv32_cpu_control.vhd

@@ -1470,7 +1470,7 @@ begin
   trap_ctrl.instr_il <= (illegal_cmd or alu_exc_i or -- illegal instruction or ALU processing exception
                          (bool_to_ulogic_f(CPU_EXTENSION_RISCV_E) and illegal_reg) or -- illegal register access in E extension
                          (bool_to_ulogic_f(CPU_EXTENSION_RISCV_C) and execute_engine.is_ici)) -- illegal compressed instruction
-                        when (execute_engine.state = EXECUTE) else '0'; -- evaluate in EXECUTE stage only
+                        when ((execute_engine.state = EXECUTE) or (execute_engine.state = ALU_WAIT)) else '0'; -- evaluate in execution stages only
 
 
 -- ****************************************************************************************************************************

rtl/core/neorv32_cpu_cp_cfu.vhd

@@ -221,16 +221,17 @@ begin
   -- as all internal computations have completed, the <control.done> signal has to be set to indicate completion. This will
   -- complete CFU instruction operation and will also write the processing result <control.result> back to the CPU register file.
   --
-  -- [NOTE] The <control.done> **has to be set at some time** - otherwise the CPU will get stalled forever.
+  -- [NOTE] If the <control.done> signal is not set within a bound time window (default = 128 cycles) the CFU operation is
+  --        automatically terminated by the hardware and an illegal instruction exception is raised. This feature can also be
+  --        be used to implement custom CFU exceptions.
 
 
   -- ----------------------------------------------------------------------------------------
   -- Final Notes
   -- ----------------------------------------------------------------------------------------
-  -- The <control> record provides something like a "keeper" that ensures correct functionality (we do not want to
-  -- stall the CPU forever) and also a simple-to-use interface hardware designers can start with. Obviously, the control
-  -- instance adds one additional cycle of latency. Advanced users can remove this default control instance to obtain
-  -- maximum throughput.
+  -- The <control> record provides something like a "keeper" that ensures correct functionality and that also provides a
+  -- simple-to-use interface hardware designers can start with. However, the control instance adds one additional cycle of
+  -- latency. Advanced users can remove this default control instance to obtain maximum throughput.
 
 
 -- ****************************************************************************************************************************
@@ -300,7 +301,7 @@ begin
             control.done   <= '1'; -- pure-combinatorial, so we are done "immediately"
           when others => -- not implemented
             control.result <= (others => '0');
-            control.done   <= '1'; -- set high to prevent permanent CPU stall
+            control.done   <= '0'; -- this will cause an illegal instruction exception after timeout
         end case;
 
       -- --------------------------------------------------------
@@ -318,7 +319,7 @@ begin
             control.done   <= madd.done; -- iterative, wait for unit to finish
           when others => -- not implemented
             control.result <= (others => '0');
-            control.done   <= '1'; -- set high to prevent permanent CPU stall
+            control.done   <= '0'; -- this will cause an illegal instruction exception after timeout
         end case;
 
       -- --------------------------------------------------------
@@ -344,7 +345,7 @@ begin
       -- --------------------------------------------------------
 
         control.result <= (others => '0');
-        control.done   <= '1'; -- set high to prevent permanent CPU stall
+        control.done   <= '0';
 
     end case;
   end process out_select;

rtl/core/neorv32_package.vhd

@@ -65,7 +65,7 @@ package neorv32_package is
 
   -- Architecture Constants (do not modify!) ------------------------------------------------
   -- -------------------------------------------------------------------------------------------
-  constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01080007"; -- NEORV32 version
+  constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01080008"; -- NEORV32 version
   constant archid_c     : natural := 19; -- official RISC-V architecture ID
 
   -- Check if we're inside the Matrix -------------------------------------------------------

rtl/core/neorv32_sysinfo.vhd

@@ -110,7 +110,7 @@ architecture neorv32_sysinfo_rtl of neorv32_sysinfo is
 
   -- system information ROM --
   type info_mem_t is array (0 to 7) of std_ulogic_vector(31 downto 0);
-  signal sysinfo_mem : info_mem_t;
+  signal sysinfo : info_mem_t;
 
 begin
 
@@ -125,79 +125,78 @@ begin
   -- Construct Info ROM ---------------------------------------------------------------------
   -- -------------------------------------------------------------------------------------------
   -- SYSINFO(0): Processor (primary) clock frequency --
-  sysinfo_mem(0) <= std_ulogic_vector(to_unsigned(CLOCK_FREQUENCY, 32));
+  sysinfo(0) <= std_ulogic_vector(to_unsigned(CLOCK_FREQUENCY, 32));
 
   -- SYSINFO(1): Custom user-defined ID --
-  sysinfo_mem(1) <= CUSTOM_ID;
+  sysinfo(1) <= CUSTOM_ID;
 
   -- SYSINFO(2): Implemented processor devices/features --
   -- Memory --
-  sysinfo_mem(2)(00) <= bool_to_ulogic_f(INT_BOOTLOADER_EN);  -- processor-internal bootloader implemented?
-  sysinfo_mem(2)(01) <= bool_to_ulogic_f(MEM_EXT_EN);         -- external memory bus interface implemented?
-  sysinfo_mem(2)(02) <= bool_to_ulogic_f(MEM_INT_IMEM_EN) and bool_to_ulogic_f(boolean(MEM_INT_IMEM_SIZE > 0)); -- processor-internal instruction memory implemented?
-  sysinfo_mem(2)(03) <= bool_to_ulogic_f(MEM_INT_DMEM_EN) and bool_to_ulogic_f(boolean(MEM_INT_DMEM_SIZE > 0)); -- processor-internal data memory implemented?
-  sysinfo_mem(2)(04) <= bool_to_ulogic_f(MEM_EXT_BIG_ENDIAN); -- is external memory bus interface using BIG-endian byte-order?
-  sysinfo_mem(2)(05) <= bool_to_ulogic_f(ICACHE_EN);          -- processor-internal instruction cache implemented?
+  sysinfo(2)(00) <= bool_to_ulogic_f(INT_BOOTLOADER_EN);   -- processor-internal bootloader implemented?
+  sysinfo(2)(01) <= bool_to_ulogic_f(MEM_EXT_EN);          -- external memory bus interface implemented?
+  sysinfo(2)(02) <= bool_to_ulogic_f(MEM_INT_IMEM_EN and (MEM_INT_IMEM_SIZE > 0)); -- processor-internal instruction memory implemented?
+  sysinfo(2)(03) <= bool_to_ulogic_f(MEM_INT_DMEM_EN and (MEM_INT_DMEM_SIZE > 0)); -- processor-internal data memory implemented?
+  sysinfo(2)(04) <= bool_to_ulogic_f(MEM_EXT_BIG_ENDIAN);  -- is external memory bus interface using BIG-endian byte-order?
+  sysinfo(2)(05) <= bool_to_ulogic_f(ICACHE_EN);           -- processor-internal instruction cache implemented?
   --
-  sysinfo_mem(2)(12 downto 06) <= (others => '0'); -- reserved
+  sysinfo(2)(12 downto 06) <= (others => '0'); -- reserved
   -- Misc --
-  sysinfo_mem(2)(13) <= bool_to_ulogic_f(is_simulation_c);     -- is this a simulation?
-  sysinfo_mem(2)(14) <= bool_to_ulogic_f(ON_CHIP_DEBUGGER_EN); -- on-chip debugger implemented?
+  sysinfo(2)(13) <= bool_to_ulogic_f(is_simulation_c);     -- is this a simulation?
+  sysinfo(2)(14) <= bool_to_ulogic_f(ON_CHIP_DEBUGGER_EN); -- on-chip debugger implemented?
   --
-  sysinfo_mem(2)(15) <= '0'; -- reserved
+  sysinfo(2)(15) <= '0'; -- reserved
   -- IO --
-  sysinfo_mem(2)(16) <= bool_to_ulogic_f(boolean(IO_GPIO_NUM > 0));    -- general purpose input/output port unit (GPIO) implemented?
-  sysinfo_mem(2)(17) <= bool_to_ulogic_f(IO_MTIME_EN);                 -- machine system timer (MTIME) implemented?
-  sysinfo_mem(2)(18) <= bool_to_ulogic_f(IO_UART0_EN);                 -- primary universal asynchronous receiver/transmitter (UART0) implemented?
-  sysinfo_mem(2)(19) <= bool_to_ulogic_f(IO_SPI_EN);                   -- serial peripheral interface (SPI) implemented?
-  sysinfo_mem(2)(20) <= bool_to_ulogic_f(IO_TWI_EN);                   -- two-wire interface (TWI) implemented?
-  sysinfo_mem(2)(21) <= bool_to_ulogic_f(boolean(IO_PWM_NUM_CH > 0));  -- pulse-width modulation unit (PWM) implemented?
-  sysinfo_mem(2)(22) <= bool_to_ulogic_f(IO_WDT_EN);                   -- watch dog timer (WDT) implemented?
-  sysinfo_mem(2)(23) <= bool_to_ulogic_f(IO_CFS_EN);                   -- custom functions subsystem (CFS) implemented?
-  sysinfo_mem(2)(24) <= bool_to_ulogic_f(IO_TRNG_EN);                  -- true random number generator (TRNG) implemented?
-  sysinfo_mem(2)(25) <= bool_to_ulogic_f(IO_SLINK_EN);                 -- stream links (SLINK) implemented?
-  sysinfo_mem(2)(26) <= bool_to_ulogic_f(IO_UART1_EN);                 -- secondary universal asynchronous receiver/transmitter (UART1) implemented?
-  sysinfo_mem(2)(27) <= bool_to_ulogic_f(IO_NEOLED_EN);                -- NeoPixel-compatible smart LED interface (NEOLED) implemented?
-  sysinfo_mem(2)(28) <= bool_to_ulogic_f(boolean(IO_XIRQ_NUM_CH > 0)); -- external interrupt controller (XIRQ) implemented?
-  sysinfo_mem(2)(29) <= bool_to_ulogic_f(IO_GPTMR_EN);                 -- general purpose timer (GPTMR) implemented?
-  sysinfo_mem(2)(30) <= bool_to_ulogic_f(IO_XIP_EN);                   -- execute in place module (XIP) implemented?
-  sysinfo_mem(2)(31) <= bool_to_ulogic_f(IO_ONEWIRE_EN);               -- 1-wire interface (ONEWIRE) implemented?
+  sysinfo(2)(16) <= bool_to_ulogic_f(IO_GPIO_NUM > 0);     -- general purpose input/output port unit (GPIO) implemented?
+  sysinfo(2)(17) <= bool_to_ulogic_f(IO_MTIME_EN);         -- machine system timer (MTIME) implemented?
+  sysinfo(2)(18) <= bool_to_ulogic_f(IO_UART0_EN);         -- primary universal asynchronous receiver/transmitter (UART0) implemented?
+  sysinfo(2)(19) <= bool_to_ulogic_f(IO_SPI_EN);           -- serial peripheral interface (SPI) implemented?
+  sysinfo(2)(20) <= bool_to_ulogic_f(IO_TWI_EN);           -- two-wire interface (TWI) implemented?
+  sysinfo(2)(21) <= bool_to_ulogic_f(IO_PWM_NUM_CH > 0);   -- pulse-width modulation unit (PWM) implemented?
+  sysinfo(2)(22) <= bool_to_ulogic_f(IO_WDT_EN);           -- watch dog timer (WDT) implemented?
+  sysinfo(2)(23) <= bool_to_ulogic_f(IO_CFS_EN);           -- custom functions subsystem (CFS) implemented?
+  sysinfo(2)(24) <= bool_to_ulogic_f(IO_TRNG_EN);          -- true random number generator (TRNG) implemented?
+  sysinfo(2)(25) <= bool_to_ulogic_f(IO_SLINK_EN);         -- stream links (SLINK) implemented?
+  sysinfo(2)(26) <= bool_to_ulogic_f(IO_UART1_EN);         -- secondary universal asynchronous receiver/transmitter (UART1) implemented?
+  sysinfo(2)(27) <= bool_to_ulogic_f(IO_NEOLED_EN);        -- NeoPixel-compatible smart LED interface (NEOLED) implemented?
+  sysinfo(2)(28) <= bool_to_ulogic_f(IO_XIRQ_NUM_CH > 0);  -- external interrupt controller (XIRQ) implemented?
+  sysinfo(2)(29) <= bool_to_ulogic_f(IO_GPTMR_EN);         -- general purpose timer (GPTMR) implemented?
+  sysinfo(2)(30) <= bool_to_ulogic_f(IO_XIP_EN);           -- execute in place module (XIP) implemented?
+  sysinfo(2)(31) <= bool_to_ulogic_f(IO_ONEWIRE_EN);       -- 1-wire interface (ONEWIRE) implemented?
 
   -- SYSINFO(3): Cache configuration --
-  sysinfo_mem(3)(03 downto 00) <= std_ulogic_vector(to_unsigned(index_size_f(ICACHE_BLOCK_SIZE),    4)) when (ICACHE_EN = true) else (others => '0'); -- i-cache: log2(block_size_in_bytes)
-  sysinfo_mem(3)(07 downto 04) <= std_ulogic_vector(to_unsigned(index_size_f(ICACHE_NUM_BLOCKS),    4)) when (ICACHE_EN = true) else (others => '0'); -- i-cache: log2(number_of_block)
-  sysinfo_mem(3)(11 downto 08) <= std_ulogic_vector(to_unsigned(index_size_f(ICACHE_ASSOCIATIVITY), 4)) when (ICACHE_EN = true) else (others => '0'); -- i-cache: log2(associativity)
-  sysinfo_mem(3)(15 downto 12) <= "0001" when (ICACHE_ASSOCIATIVITY > 1) and (ICACHE_EN = true) else (others => '0'); -- i-cache: replacement strategy (LRU only (yet))
+  sysinfo(3)(03 downto 00) <= std_ulogic_vector(to_unsigned(index_size_f(ICACHE_BLOCK_SIZE),    4)) when (ICACHE_EN = true) else (others => '0'); -- i-cache: log2(block_size_in_bytes)
+  sysinfo(3)(07 downto 04) <= std_ulogic_vector(to_unsigned(index_size_f(ICACHE_NUM_BLOCKS),    4)) when (ICACHE_EN = true) else (others => '0'); -- i-cache: log2(number_of_block)
+  sysinfo(3)(11 downto 08) <= std_ulogic_vector(to_unsigned(index_size_f(ICACHE_ASSOCIATIVITY), 4)) when (ICACHE_EN = true) else (others => '0'); -- i-cache: log2(associativity)
+  sysinfo(3)(15 downto 12) <= "0001" when (ICACHE_ASSOCIATIVITY > 1) and (ICACHE_EN = true) else (others => '0'); -- i-cache: replacement strategy (LRU only (yet))
   --
-  sysinfo_mem(3)(19 downto 16) <= (others => '0'); -- reserved - d-cache: log2(block_size)
-  sysinfo_mem(3)(23 downto 20) <= (others => '0'); -- reserved - d-cache: log2(num_blocks)
-  sysinfo_mem(3)(27 downto 24) <= (others => '0'); -- reserved - d-cache: log2(associativity)
-  sysinfo_mem(3)(31 downto 28) <= (others => '0'); -- reserved - d-cache: replacement strategy
+  sysinfo(3)(19 downto 16) <= (others => '0'); -- reserved - d-cache: log2(block_size)
+  sysinfo(3)(23 downto 20) <= (others => '0'); -- reserved - d-cache: log2(num_blocks)
+  sysinfo(3)(27 downto 24) <= (others => '0'); -- reserved - d-cache: log2(associativity)
+  sysinfo(3)(31 downto 28) <= (others => '0'); -- reserved - d-cache: replacement strategy
 
   -- SYSINFO(4): Base address of instruction memory space --
-  sysinfo_mem(4) <= ispace_base_c; -- defined in neorv32_package.vhd file
+  sysinfo(4) <= ispace_base_c; -- defined in neorv32_package.vhd file
 
   -- SYSINFO(5): Base address of data memory space --
-  sysinfo_mem(5) <= dspace_base_c; -- defined in neorv32_package.vhd file
+  sysinfo(5) <= dspace_base_c; -- defined in neorv32_package.vhd file
 
   -- SYSINFO(6): Size of IMEM in bytes --
-  sysinfo_mem(6) <= std_ulogic_vector(to_unsigned(MEM_INT_IMEM_SIZE, 32)) when (MEM_INT_IMEM_EN = true) else (others => '0');
+  sysinfo(6) <= std_ulogic_vector(to_unsigned(MEM_INT_IMEM_SIZE, 32)) when (MEM_INT_IMEM_EN = true) else (others => '0');
 
   -- SYSINFO(7): Size of DMEM in bytes --
-  sysinfo_mem(7) <= std_ulogic_vector(to_unsigned(MEM_INT_DMEM_SIZE, 32)) when (MEM_INT_DMEM_EN = true) else (others => '0');
+  sysinfo(7) <= std_ulogic_vector(to_unsigned(MEM_INT_DMEM_SIZE, 32)) when (MEM_INT_DMEM_EN = true) else (others => '0');
 
 
   -- Read Access ----------------------------------------------------------------------------
   -- -------------------------------------------------------------------------------------------
   read_access: process(clk_i)
   begin
     if rising_edge(clk_i) then
-      ack_o <= rden;
-      err_o <= wren; -- read-only!
+      ack_o  <= rden;
+      err_o  <= wren; -- read-only!
+      data_o <= (others => '0');
       if (rden = '1') then
-        data_o <= sysinfo_mem(to_integer(unsigned(addr)));
-      else
-        data_o <= (others => '0');
+        data_o <= sysinfo(to_integer(unsigned(addr)));
       end if;
     end if;
   end process read_access;

sw/example/demo_cfu/main.c

@@ -3,7 +3,7 @@
 // # ********************************************************************************************* #
 // # BSD 3-Clause License                                                                          #
 // #                                                                                               #
-// # Copyright (c) 2022, Stephan Nolting. All rights reserved.                                     #
+// # Copyright (c) 2023, Stephan Nolting. All rights reserved.                                     #
 // #                                                                                               #
 // # Redistribution and use in source and binary forms, with or without modification, are          #
 // # permitted provided that the following conditions are met:                                     #
@@ -208,6 +208,20 @@ int main() {
   }
 
 
+  // ----------------------------------------------------------
+  // Unimplemented (=illegal) R3-type instruction
+  // ----------------------------------------------------------
+
+  neorv32_uart0_printf("\n--- CFU Unimplemented (= illegal) R3-Type ---\n");
+  for (i=0; i<TESTCASES; i++) {
+    rs1 = xorshift32();
+    rs2 = xorshift32();
+    // this funct3 is NOT implemented by the default CFU hardware causing an illegal instruction exception
+    neorv32_uart0_printf("%u: neorv32_cfu_r3_instr( funct7=0b0000000, funct3=0b111, [rs1]=0x%x, [rs2]=0x%x ) = ", i, rs1, rs2);
+    neorv32_uart0_printf("0x%x\n", neorv32_cfu_r3_instr(0b0000000, 0b111, rs1, rs2));
+  }
+
+
   neorv32_uart0_printf("\nCFU demo program completed.\n");
   return 0;
 }