Add @let directive, start pondering interrupt control

1 files changed, 15 insertions, 5 deletions

diff --git a/src/asm_pass3.py b/src/asm_pass3.py
index 76e7b84..5221f6d 100644
--- a/src/asm_pass3.py
+++ b/src/asm_pass3.py
@@ -16,21 +16,24 @@ class Result3:
   lines: list[Result3Line]
   options: Options
   operations: OpExpansionDict
-  labels: dict[str, int]
+  symbols: dict[str, int]
 
 def pass_3(result2: Result2) -> Result3:
   result_lines: list[Result3Line] = []
-  labels: dict[str, int] = {}
+  symbols: dict[str, int] = {}
   address = 0
 
   for line in result2.lines:
     keyword, *args = line.parts
     match keyword:
       case "@address":
-        address = eval(args[0])
+        address = eval_expr(symbols, args[0])
         continue
       case "@label":
-        labels[args[0]] = address
+        symbols[args[0]] = address
+        continue
+      case "@let":
+        symbols[args[0]] = eval_expr(symbols, args[1])
         continue
       case _:
         result_lines.append(Result3Line(
@@ -42,9 +45,16 @@ def pass_3(result2: Result2) -> Result3:
         ))
         address += 1
 
+  result_lines.sort(key=lambda l: l.address)
+  for result_line in result_lines:
+    rows_with_same_addr = list(filter(lambda l: l.address == result_line.address, result_lines))
+    n = len(rows_with_same_addr)
+    if n > 1:
+      formatted = "\n".join(map(lambda l: " ".join(l.parts), rows_with_same_addr))
+      raise Exception(f"Overlapping segments: address 0x{result_line.address:>04x} has conflicting definitions:\n{formatted}")
   return Result3(
     operations=result2.operations,
     options=result2.options,
     lines=result_lines,
-    labels=labels,
+    symbols=symbols,
   )