README: describe more syntax

README.rst

@@ -124,9 +124,9 @@ emit "add mode 1" via the ``DMA1`` and ``DMAH1`` mnemonics.
 DMA "add mode" and bytes
 ------------------------
 
-All of the documentation you have read is invalid; here is the correct
-relationship between DMA "add mode" mnemonics, and the number of
-incremented bytes:
+All of the documentation you have read is invalid; this is the correct
+relationship between DMA "add mode" mnemonics. The right columns represent the
+the increment added an offset of RA0/WA0 after each bus transfer:
 
 .. list-table::
    :header-rows: 1
@@ -159,3 +159,63 @@ incremented bytes:
    * - DMA64
      - 4 bytes
      - 128 bytes
+
+Note that the DMA transfer length is always decremented by 1 after 4 bytes are
+transferred, regardless of the size of the bus transfer.
+
+The SCU manual (ST-97-R5-072694) contains this contradictory text:
+
+   Only add numbers 0 and 1 are valid for the A-Bus and the write unit is
+   32bit. [...] Write unit is 16bit; 32bit data is divided in half and written
+   at intervals of 16X (0-64).
+
+"Multiply the 'add number' by the [number of bytes per transfer] **depending on
+the value of WA0/RA0**" is completely incorrect. The text in the original
+Japanese document is also incorrect.
+
+Syntax features that are supported, but with misleading consequences
+====================================================================
+
+``NOP`` mnemonics inside OP instructions
+----------------------------------------
+
+In both scu-dsp-asm and ``dspasm.exe``, ALU, X-bus, Y-bus, and D1-bus mnemonics
+may appear in any order in a single OP instruction and/or line of source code.
+
+From a grammar perspective, it is impossible to disambiguate which bus a ``NOP``
+is referring to. For example, this is valid code:
+
+.. code::
+
+   NOP  NOP  NOP  NOP  MOV MUL,P
+
+Even though it visually might appear that the X-bus operation might be
+simultaneously ``NOP`` and ``MOV MUL,P``, due to syntactical ambiguity the
+assembler is not able to generate an error for this case.
+
+There is no restriction on the number of ``NOP`` values that can appear on a
+single line.
+
+Feel free to use this syntax feature if desired stylistically, but be aware
+scu-dsp-asm is not able to verify intent, and does not/can not generate errors
+related to a "conflict" between a ``NOP`` mnemonic and any other bus operation.
+
+Immediates with ``:``-suffixes or ``#``-prefixes
+------------------------------------------------
+
+In both scu-dsp-asm and ``dspasm.exe``, neither of these characters mean
+anything in the grammar. If encountered, they are ignored.
+
+For example, all of the following is valid source code:
+
+.. code::
+
+   MVI #1,MC0
+   MVI 1:,MC0
+   MVI #foobar,MC0
+   MVI #foobar:,MC0
+   MVI #1+1:,MC0
+   MVI #(1+1):,MC0
+
+Feel free to use these characters if desired stylistically, but be aware that
+scu-dsp-asm does not generate errors regardless of how they are used.

release.sh

@@ -2,6 +2,7 @@ V=2
 M=scu-dsp-asm.$V
 
 make TARGET=x86_64-pc-linux-gnu-       MAIN=$M.Linux.x86_64       clean all
+make TARGET=aarch64-unknown-linux-gnu- MAIN=$M.Linux.aarch64      clean all
 make TARGET=x86_64-w64-mingw32-        MAIN=$M.Windows.x86_64.exe clean all
 make TARGET=i686-w64-mingw32-          MAIN=$M.Windows.i686.exe   clean all
 #make MAIN=$M.MacOS-Ventura.x86_64 clean all