Allow selecting cpu to assemble for from cmdline

Select cpu with -c when running the assembler (--mcpu as used by
Espressif's esp32ulp-elf-as also works). The possible values are
'esp32' and 'esp32s2'. (Note esp32s2 also works for the ESP32-S3,
because those two MCUs share the same ULP-FSM binary format).

If no cpu is specified the original 'esp32' will be used as before.

Author: wnienhaus

docs/index.rst

@@ -58,6 +58,13 @@ follows:
    cd micropython-esp32-ulp
    micropython -m esp32_ulp path/to/code.S  # this results in path/to/code.ulp
 
+The assembler supports selecting a CPU to assemble for using the ``-c`` option
+(valid cpu's are ``esp32`` and ``esp32s2``):
+
+.. code-block:: shell
+
+   micropython -m esp32_ulp -c esp32s2 path/to/code.S  # assemble for an ESP32-S2
+
 
 More examples
 +++++++++++++
@@ -91,7 +98,7 @@ That file can then be loaded directly without assembling the source again.
    .. code-block:: python
 
       import esp32_ulp
-      esp32_ulp.assemble_file('code.S')  # this results in code.ulp
+      esp32_ulp.assemble_file('code.S', cpu='esp32')  # this results in code.ulp
 
 2. The above prints out the offsets of all global symbols/labels. For the next
    step, you will need to note down the offset of the label, which represents

esp32_ulp/__init__.py

@@ -6,8 +6,8 @@
 garbage_collect('after import')
 
 
-def src_to_binary(src):
-    assembler = Assembler()
+def src_to_binary(src, cpu):
+    assembler = Assembler(cpu)
     src = preprocess(src)
     assembler.assemble(src, remove_comments=False)  # comments already removed by preprocessor
     garbage_collect('before symbols export')
@@ -19,11 +19,11 @@ def src_to_binary(src):
     return make_binary(text, data, bss_len)
 
 
-def assemble_file(filename):
+def assemble_file(filename, cpu):
     with open(filename) as f:
         src = f.read()
 
-    binary = src_to_binary(src)
+    binary = src_to_binary(src, cpu)
 
     if filename.endswith('.s') or filename.endswith('.S'):
         filename = filename[:-2]

esp32_ulp/__main__.py

@@ -2,10 +2,18 @@
 from . import assemble_file
 
 
-def main(fn):
-    assemble_file(fn)
+def main(fn, cpu):
+    assemble_file(fn, cpu)
 
 
 if __name__ == '__main__':
-    main(sys.argv[1])
+    cpu = 'esp32'
+    filename = sys.argv[1]
+    if len(sys.argv) > 3:
+        if sys.argv[1] in ('-c', '--mcpu'):
+            cpu = sys.argv[2].lower()
+            if cpu not in ('esp32', 'esp32s2'):
+                raise ValueError('Invalid cpu')
+            filename = sys.argv[3]
+    main(filename, cpu)
 

esp32_ulp/assemble.py

@@ -3,7 +3,6 @@
 """
 
 import re
-from . import opcodes
 from .nocomment import remove_comments as do_remove_comments
 from .util import garbage_collect
 
@@ -88,9 +87,19 @@ def set_global(self, symbol):
 
 class Assembler:
 
-    def __init__(self, symbols=None, bases=None, globals=None):
+    def __init__(self, cpu='esp32', symbols=None, bases=None, globals=None):
+        if cpu == 'esp32':
+            opcode_module = 'opcodes'
+        elif cpu == 'esp32s2':
+            opcode_module = 'opcodes_s2'
+        else:
+            raise ValueError('Invalid cpu')
+
+        relative_import = 1 if '/' in __file__ else 0
+        self.opcodes = __import__(opcode_module, None, None, [], relative_import)
+
         self.symbols = SymbolTable(symbols or {}, bases or {}, globals or {})
-        opcodes.symbols = self.symbols  # XXX dirty hack
+        self.opcodes.symbols = self.symbols  # XXX dirty hack
 
         # regex for parsing assembly lines
         # format: [[whitespace]label:][whitespace][opcode[whitespace arg[,arg...]]]
@@ -223,7 +232,7 @@ def d_align(self, align=4, fill=None):
             self.fill(self.section, amount, fill)
 
     def d_set(self, symbol, expr):
-        value = int(opcodes.eval_arg(expr))
+        value = int(self.opcodes.eval_arg(expr))
         self.symbols.set_sym(symbol, ABS, None, value)
 
     def d_global(self, symbol):
@@ -264,13 +273,13 @@ def assembler_pass(self, lines):
                 else:
                     # machine instruction
                     opcode_lower = opcode.lower()
-                    func = getattr(opcodes, 'i_' + opcode_lower, None)
+                    func = getattr(self.opcodes, 'i_' + opcode_lower, None)
                     if func is not None:
                         if self.a_pass == 1:
                             # during the first pass, symbols are not all known yet.
                             # so we add empty instructions to the section, to determine
                             # section sizes and symbol offsets for pass 2.
-                            result = (0,) * opcodes.no_of_instr(opcode_lower, args)
+                            result = (0,) * self.opcodes.no_of_instr(opcode_lower, args)
                         else:
                             result = func(*args)
 

examples/blink.py

@@ -93,7 +93,7 @@
   halt  # go back to sleep until next wakeup period
 """
 
-binary = src_to_binary(source)
+binary = src_to_binary(source, cpu="esp32")  # cpu is esp32 or esp32s2
 
 load_addr, entry_addr = 0, 8
 

examples/counter.py

@@ -25,7 +25,7 @@
             halt             # halt ULP co-prozessor (until it gets waked up again)
 """
 
-binary = src_to_binary(source)
+binary = src_to_binary(source, cpu="esp32")  # cpu is esp32 or esp32s2
 
 load_addr, entry_addr = 0, 4
 

examples/readgpio.py

@@ -52,7 +52,7 @@
             halt
 """
 
-binary = src_to_binary(source)
+binary = src_to_binary(source, cpu="esp32")  # cpu is esp32 or esp32s2
 
 load_addr, entry_addr = 0, 4