🐛 Make sure IMEM/DMEM sizes are a power of two

CHANGELOG.md

@@ -6,9 +6,9 @@ Releases are linked and highlighted. The latest release is
 A list of all releases can be found [here](https://github.com/stnolting/neorv32/releases).
 
 Starting with version `1.5.7` this project uses [semantic versioning](https://semver.org).
-The _version identifier_ uses an additional **custom** element (`MAJOR.MINOR.PATCH.custom`)
-to track _individual_ changes. The identifier number is incremented with every core RTL
-modification and also by major framework modifications.
+The **version identifier** uses an additional custom element (`MAJOR.MINOR.PATCH.custom`)
+to track individual changes. The identifier is incremented by every core RTL modification
+and also by major software/project changes.
 
 The version identifier is globally defined by the `hw_version_c` constant in the main VHDL
 [package file](https://github.com/stnolting/neorv32/blob/main/rtl/core/neorv32_package.vhd).
@@ -32,6 +32,7 @@ mimpid = 0x01040312 -> Version 01.04.03.12 -> v1.4.3.12
 
 | Date (*dd.mm.yyyy*) | Version | Comment |
 |:-------------------:|:-------:|:--------|
+| 27.07.2023 | 1.8.7.2 | :bug: make sure that IMEM/DMEM size is always a power of two; [#658](https://github.com/stnolting/neorv32/pull/658) |
 | 27.07.2023 | 1.8.7.1 | :warning: remove `CUSTOM_ID` generic; cleanup and re-layout `NEORV32_SYSINFO.SOC` bits; (:bug:) fix gateway's generics (`positive` -> `natural` as these generics are allowed to be zero); [#657](https://github.com/stnolting/neorv32/pull/657) |
 | 26.07.2023 | [**:rocket:1.8.7**](https://github.com/stnolting/neorv32/releases/tag/v1.8.7) | **New release** |
 | 24.07.2023 | 1.8.6.10 | :bug: fixing some LR/SC design flaws; [#654](https://github.com/stnolting/neorv32/pull/654) |

docs/datasheet/soc.adoc

@@ -232,10 +232,10 @@ The generic type "`suv(x:y)`" is an abbreviation for "`std_ulogic_vector(x downt
 | `AMO_RVS_GRANULARITY`   | natural   | 4          | Size in bytes, has to be a power of 2, min 4.
 4+^| **Internal <<_instruction_memory_imem>>**
 | `MEM_INT_IMEM_EN`       | boolean   | false      | Implement the processor-internal instruction memory.
-| `MEM_INT_IMEM_SIZE`     | natural   | 16*1024    | Size in bytes of the processor internal instruction memory.
+| `MEM_INT_IMEM_SIZE`     | natural   | 16*1024    | Size in bytes of the processor internal instruction memory (use a power of 2).
 4+^| **Internal <<_data_memory_dmem>>**
 | `MEM_INT_DMEM_EN`       | boolean   | false      | Implement the processor-internal data memory.
-| `MEM_INT_DMEM_SIZE`     | natural   | 8*1024     | Size in bytes of the processor-internal data memory.
+| `MEM_INT_DMEM_SIZE`     | natural   | 8*1024     | Size in bytes of the processor-internal data memory (use a power of 2).
 4+^| **<<_processor_internal_instruction_cache_icache>>**
 | `ICACHE_EN`             | boolean   | false      | Implement the instruction cache.
 | `ICACHE_NUM_BLOCKS`     | natural   | 4          | Number of blocks ("pages" or "lines") Has to be a power of two.

docs/datasheet/soc_dmem.adoc

@@ -10,7 +10,7 @@
 | Software driver file(s): | none                         | _implicitly used_
 | Top entity port:         | none                         | 
 | Configuration generics:  | `MEM_INT_DMEM_EN`            | implement processor-internal DMEM when `true`
-|                          | `MEM_INT_DMEM_SIZE`          | DMEM size in bytes
+|                          | `MEM_INT_DMEM_SIZE`          | DMEM size in bytes (use a power of 2)
 | CPU interrupts:          | none                         | 
 |=======================
 
@@ -20,6 +20,12 @@ the memory is mapped into the data memory space and located right at the beginni
 space (default `dspace_base_c` = 0x80000000), see <<_address_space>>. The DMEM is always implemented
 as true RAM.
 
+.Memory Size
+[IMPORTANT]
+If the configured memory size (via the `MEM_INT_IMEM_SIZE` generic) is **not** a power of two the actual memory
+size will be auto-adjusted to the next power of two (e.g. configuring a memory size of 60kB will result in a
+physical memory size of 64kB).
+
 .VHDL Source File
 [NOTE]
 The actual DMEM is split into two design files: a plain entity definition (`neorv32_dmem.entity.vhd`) and the actual

docs/datasheet/soc_imem.adoc

@@ -10,7 +10,7 @@
 | Software driver file(s): | none                         | _implicitly used_
 | Top entity port:         | none                         | 
 | Configuration generics:  | `MEM_INT_IMEM_EN`            | implement processor-internal IMEM when `true`
-|                          | `MEM_INT_IMEM_SIZE`          | IMEM size in bytes
+|                          | `MEM_INT_IMEM_SIZE`          | IMEM size in bytes (use a power of 2)
 |                          | `INT_BOOTLOADER_EN`          | use internal bootloader when `true` (implements IMEM as _uninitialized_ RAM, otherwise the IMEM is implemented an _pre-intialized_ ROM)
 | CPU interrupts:          | none                         | 
 |=======================
@@ -31,6 +31,12 @@ image. The compiler toolchain provides an option to generate and override the de
 `rtl/core/neorv32_application_image.vhd`, which is automatically inserted into the IMEM. If the IMEM is implemented
 as RAM (default), the memory will **not be initialized at all**.
 
+.Memory Size
+[IMPORTANT]
+If the configured memory size (via the `MEM_INT_IMEM_SIZE` generic) is **not** a power of two the actual memory
+size will be auto-adjusted to the next power of two (e.g. configuring a memory size of 60kB will result in a
+physical memory size of 64kB).
+
 .VHDL Source File
 [NOTE]
 The actual IMEM is split into two design files: a plain entity definition (`neorv32_imem.entity.vhd`) and the actual

rtl/core/mem/neorv32_dmem.default.vhd

@@ -68,6 +68,9 @@ begin
   assert false report
     "NEORV32 PROCESSOR CONFIG NOTE: Using DEFAULT platform-agnostic DMEM." severity note;
 
+  assert not (is_power_of_two_f(DMEM_SIZE) = false) report
+    "NEORV32 PROCESSOR CONFIG ERROR: Internal DMEM size has to be a power of two!" severity error;
+
   assert false report
     "NEORV32 PROCESSOR CONFIG NOTE: Implementing processor-internal DMEM (RAM, " & natural'image(DMEM_SIZE) &
     " bytes)." severity note;

rtl/core/mem/neorv32_dmem.legacy.vhd

@@ -69,6 +69,9 @@ begin
   assert false report
     "NEORV32 PROCESSOR CONFIG NOTE: Using legacy HDL style DMEM." severity note;
 
+  assert not (is_power_of_two_f(DMEM_SIZE) = false) report
+    "NEORV32 PROCESSOR CONFIG ERROR: Internal DMEM size has to be a power of two!" severity error;
+
   assert false report
     "NEORV32 PROCESSOR CONFIG NOTE: Implementing processor-internal DMEM (RAM, " & natural'image(DMEM_SIZE) &
     " bytes)." severity note;

rtl/core/mem/neorv32_imem.default.vhd

@@ -85,6 +85,9 @@ begin
   assert false report
     "NEORV32 PROCESSOR CONFIG NOTE: Using DEFAULT platform-agnostic IMEM." severity note;
 
+  assert not (is_power_of_two_f(IMEM_SIZE) = false) report
+    "NEORV32 PROCESSOR CONFIG ERROR: Internal IMEM size has to be a power of two!" severity error;
+
   assert not (IMEM_AS_IROM = true) report
     "NEORV32 PROCESSOR CONFIG NOTE: Implementing processor-internal IMEM as ROM (" & natural'image(IMEM_SIZE) &
     " bytes), pre-initialized with application (" & natural'image(imem_app_size_c) & " bytes)." severity note;

rtl/core/mem/neorv32_imem.legacy.vhd

@@ -86,6 +86,9 @@ begin
   assert false report
     "NEORV32 PROCESSOR CONFIG NOTE: Using legacy HDL style IMEM." severity note;
 
+  assert not (is_power_of_two_f(IMEM_SIZE) = false) report
+    "NEORV32 PROCESSOR CONFIG ERROR: Internal IMEM size has to be a power of two!" severity error;
+
   assert not (IMEM_AS_IROM = true) report
     "NEORV32 PROCESSOR CONFIG NOTE: Implementing processor-internal IMEM as ROM (" & natural'image(IMEM_SIZE) &
     " bytes), pre-initialized with application (" & natural'image(imem_app_size_c) & " bytes)." severity note;

rtl/core/neorv32_dmem.entity.vhd

@@ -41,7 +41,7 @@ use neorv32.neorv32_package.all;
 
 entity neorv32_dmem is
   generic (
-    DMEM_SIZE : natural -- processor-internal instruction memory size in bytes
+    DMEM_SIZE : natural -- processor-internal instruction memory size in bytes, has to be a power of 2
   );
   port (
     clk_i     : in  std_ulogic; -- global clock line

rtl/core/neorv32_imem.entity.vhd

@@ -41,7 +41,7 @@ use neorv32.neorv32_package.all;
 
 entity neorv32_imem is
   generic (
-    IMEM_SIZE    : natural; -- processor-internal instruction memory size in bytes
+    IMEM_SIZE    : natural; -- processor-internal instruction memory size in bytes, has to be a power of 2
     IMEM_AS_IROM : boolean  -- implement IMEM as pre-initialized read-only memory?
   );
   port (

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"01080701"; -- hardware version
+  constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01080702"; -- hardware version
   constant archid_c     : natural := 19; -- official RISC-V architecture ID
   constant XLEN         : natural := 32; -- native data path width, do not change!
 
@@ -919,10 +919,10 @@ package neorv32_package is
       AMO_RVS_GRANULARITY          : natural := 4;      -- size in bytes, has to be a power of 2, min 4
       -- Internal Instruction memory (IMEM) --
       MEM_INT_IMEM_EN              : boolean := false;  -- implement processor-internal instruction memory
-      MEM_INT_IMEM_SIZE            : natural := 16*1024; -- size of processor-internal instruction memory in bytes
+      MEM_INT_IMEM_SIZE            : natural := 16*1024; -- size of processor-internal instruction memory in bytes (use a power of 2)
       -- Internal Data memory (DMEM) --
       MEM_INT_DMEM_EN              : boolean := false;  -- implement processor-internal data memory
-      MEM_INT_DMEM_SIZE            : natural := 8*1024; -- size of processor-internal data memory in bytes
+      MEM_INT_DMEM_SIZE            : natural := 8*1024; -- size of processor-internal data memory in bytes (use a power of 2)
       -- Internal Instruction Cache (iCACHE) --
       ICACHE_EN                    : boolean := false;  -- implement instruction cache
       ICACHE_NUM_BLOCKS            : natural := 4;      -- i-cache: number of blocks (min 1), has to be a power of 2

rtl/core/neorv32_top.vhd

@@ -88,11 +88,11 @@ entity neorv32_top is
 
     -- Internal Instruction memory (IMEM) --
     MEM_INT_IMEM_EN              : boolean := false;  -- implement processor-internal instruction memory
-    MEM_INT_IMEM_SIZE            : natural := 16*1024; -- size of processor-internal instruction memory in bytes
+    MEM_INT_IMEM_SIZE            : natural := 16*1024; -- size of processor-internal instruction memory in bytes (use a power of 2)
 
     -- Internal Data memory (DMEM) --
     MEM_INT_DMEM_EN              : boolean := false;  -- implement processor-internal data memory
-    MEM_INT_DMEM_SIZE            : natural := 8*1024; -- size of processor-internal data memory in bytes
+    MEM_INT_DMEM_SIZE            : natural := 8*1024; -- size of processor-internal data memory in bytes (use a power of 2)
 
     -- Internal Instruction Cache (iCACHE) --
     ICACHE_EN                    : boolean := false;  -- implement instruction cache
@@ -261,6 +261,15 @@ architecture neorv32_top_rtl of neorv32_top is
   constant io_xirq_en_c    : boolean := boolean(XIRQ_NUM_CH > 0);
   constant io_pwm_en_c     : boolean := boolean(IO_PWM_NUM_CH > 0);
 
+  -- make sure physical memory sizes are a power of two --
+  constant imem_size_valid_c : boolean := is_power_of_two_f(MEM_INT_IMEM_SIZE);
+  constant imem_size_pow2_c  : natural := 2**index_size_f(MEM_INT_IMEM_SIZE);
+  constant imem_size_c       : natural := cond_sel_natural_f(imem_size_valid_c, MEM_INT_IMEM_SIZE, imem_size_pow2_c);
+  --
+  constant dmem_size_valid_c : boolean := is_power_of_two_f(MEM_INT_DMEM_SIZE);
+  constant dmem_size_pow2_c  : natural := 2**index_size_f(MEM_INT_DMEM_SIZE);
+  constant dmem_size_c       : natural := cond_sel_natural_f(dmem_size_valid_c, MEM_INT_DMEM_SIZE, dmem_size_pow2_c);
+
   -- reset generator --
   signal rstn_ext_sreg, rstn_int_sreg : std_ulogic_vector(3 downto 0);
   signal rstn_ext, rstn_int, rstn_wdt : std_ulogic;
@@ -381,11 +390,13 @@ begin
     assert not ((INT_BOOTLOADER_EN = false) and (MEM_INT_IMEM_EN = false)) report
       "NEORV32 PROCESSOR CONFIG NOTE: Boot configuration = direct boot from memory (processor-external memory)." severity note;
 
-    -- memory layout --
-    assert not (mem_ispace_base_c /= x"00000000") report
-      "NEORV32 PROCESSOR CONFIG WARNING! Non-default base address for INSTRUCTION ADDRESS SPACE. Make sure this is sync with the software framework." severity warning;
-    assert not (mem_dspace_base_c /= x"80000000") report
-      "NEORV32 PROCESSOR CONFIG WARNING! Non-default base address for DATA ADDRESS SPACE. Make sure this is sync with the software framework." severity warning;
+    -- internal memory sizes --
+    assert not ((imem_size_valid_c = false) and (MEM_INT_IMEM_EN = true)) report
+      "NEORV32 PROCESSOR CONFIG WARNING: Configured internal IMEM size (" & natural'image(MEM_INT_IMEM_SIZE) & " bytes) is not a power of two. " &
+      "Auto-increasing memory size to the next power of two (" & natural'image(imem_size_c) & " bytes)" severity warning;
+    assert not ((dmem_size_valid_c = false) and (MEM_INT_DMEM_EN = true)) report
+      "NEORV32 PROCESSOR CONFIG WARNING: Configured internal DMEM size (" & natural'image(MEM_INT_DMEM_SIZE) & " bytes) is not a power of two. " &
+      "Auto-increasing memory size to the next power of two (" & natural'image(dmem_size_c) & " bytes)" severity warning;
 
     -- on-chip debugger --
     assert not (ON_CHIP_DEBUGGER_EN = true) report
@@ -719,11 +730,11 @@ begin
     -- IMEM port --
     IMEM_ENABLE => MEM_INT_IMEM_EN,
     IMEM_BASE   => mem_ispace_base_c,
-    IMEM_SIZE   => MEM_INT_IMEM_SIZE,
+    IMEM_SIZE   => imem_size_c,
     -- DMEM port --
     DMEM_ENABLE => MEM_INT_DMEM_EN,
     DMEM_BASE   => mem_dspace_base_c,
-    DMEM_SIZE   => MEM_INT_DMEM_SIZE,
+    DMEM_SIZE   => dmem_size_c,
     -- XIP port --
     XIP_ENABLE  => IO_XIP_EN,
     XIP_BASE    => mem_xip_base_c,
@@ -773,10 +784,10 @@ begin
     -- Processor-Internal Instruction Memory (IMEM) -------------------------------------------
     -- -------------------------------------------------------------------------------------------
     neorv32_int_imem_inst_true:
-    if (MEM_INT_IMEM_EN = true) and (MEM_INT_IMEM_SIZE > 0) generate
+    if (MEM_INT_IMEM_EN = true) and (imem_size_c > 0) generate
       neorv32_int_imem_inst: entity neorv32.neorv32_imem
       generic map (
-        IMEM_SIZE    => MEM_INT_IMEM_SIZE,
+        IMEM_SIZE    => imem_size_c,
         IMEM_AS_IROM => imem_as_rom_c
       )
       port map (
@@ -787,18 +798,18 @@ begin
     end generate;
 
     neorv32_int_imem_inst_false:
-    if (MEM_INT_IMEM_EN = false) or (MEM_INT_IMEM_SIZE = 0) generate
+    if (MEM_INT_IMEM_EN = false) or (imem_size_c = 0) generate
       imem_rsp <= rsp_terminate_c;
     end generate;
 
 
     -- Processor-Internal Data Memory (DMEM) --------------------------------------------------
     -- -------------------------------------------------------------------------------------------
     neorv32_int_dmem_inst_true:
-    if (MEM_INT_DMEM_EN = true) and (MEM_INT_DMEM_SIZE > 0) generate
+    if (MEM_INT_DMEM_EN = true) and (dmem_size_c > 0) generate
       neorv32_int_dmem_inst: entity neorv32.neorv32_dmem
       generic map (
-        DMEM_SIZE => MEM_INT_DMEM_SIZE
+        DMEM_SIZE => dmem_size_c
       )
       port map (
         clk_i     => clk_i,
@@ -808,7 +819,7 @@ begin
     end generate;
 
     neorv32_int_dmem_inst_false:
-    if (MEM_INT_DMEM_EN = false) or (MEM_INT_DMEM_SIZE = 0) generate
+    if (MEM_INT_DMEM_EN = false) or (dmem_size_c = 0) generate
       dmem_rsp <= rsp_terminate_c;
     end generate;
 
@@ -1473,10 +1484,10 @@ begin
       PMP_NUM_REGIONS      => PMP_NUM_REGIONS,
       -- internal Instruction memory --
       MEM_INT_IMEM_EN      => MEM_INT_IMEM_EN,
-      MEM_INT_IMEM_SIZE    => MEM_INT_IMEM_SIZE,
+      MEM_INT_IMEM_SIZE    => imem_size_c,
       -- Internal Data memory --
       MEM_INT_DMEM_EN      => MEM_INT_DMEM_EN,
-      MEM_INT_DMEM_SIZE    => MEM_INT_DMEM_SIZE,
+      MEM_INT_DMEM_SIZE    => dmem_size_c,
       -- Instruction cache --
       ICACHE_EN            => ICACHE_EN,
       ICACHE_NUM_BLOCKS    => ICACHE_NUM_BLOCKS,