implement .set directive (only ints as expr for now), fixes #14

Author: ThomasWaldmann

demo.S

@@ -2,6 +2,8 @@
 
             .text
 
+            .set constant42, 42
+
 textstart:  ld r0, r1, 0    # a comment!
             st r0, r1, 0    // another comment!
             add r0, r1, r2
@@ -19,6 +21,7 @@ textstart:  ld r0, r1, 0    # a comment!
             move r0, r1
             move r0, 42
             move r0, textstart  # moves abs addr of textstart to r0
+            move r0, constant42
             stage_rst
             stage_inc 42
             stage_dec 23

esp32_ulp/assemble.py

@@ -215,6 +215,10 @@ def d_skip(self, amount, fill=None):
 
     d_space = d_skip
 
+    def d_set(self, symbol, expr):
+        value = int(expr)  # TODO: support more than just integers
+        self.symbols.set_sym(symbol, ABS, None, value)
+
     def append_data(self, wordlen, args):
         data = [int(arg).to_bytes(wordlen, 'little') for arg in args]
         self.append_section(b''.join(data))

tests/compat/symbols.S

@@ -1,7 +1,10 @@
             .text
 
+            .set constant42, 42
+
 start:      move r0, data0
             move r1, data1
+            move r2, constant42
 
             # count from 0 .. 42 in stage register
             stage_rst