arch: Switch to a new state to process macrocoop headers.

The "header" of a macroop definition is the part after "def rom" but
before the "{". This is pretty minimal now, but will be more complex
once macros are introduced.

Change-Id: I002d6501a015f46be6ae28b8d2a5e6064438da32
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/56328
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/arch/micro_asm.py

@@ -197,6 +197,7 @@ tokens = reserved + (
 states = (
     ('asm', 'exclusive'),
     ('params', 'exclusive'),
+    ('header', 'exclusive'),
 )
 
 reserved_map = { }
@@ -244,17 +245,27 @@ def t_asm_ID(t):
         t.lexer.push_state('params')
     return t
 
+def t_header_ID(t):
+    r'[A-Za-z_]\w*'
+    return t
+
 # If there is a label and you're -not- in the assembler (which would be caught
 # above), don't start looking for parameters.
 def t_ANY_ID(t):
     r'[A-Za-z_]\w*'
     t.type = reserved_map.get(t.value, 'ID')
+    if t.type == 'MACROOP':
+        t.lexer.push_state('asm')
+        t.lexer.push_state('header')
+    elif t.type == 'ROM':
+        t.lexer.push_state('asm')
+        t.lexer.push_state('header')
     return t
 
 # Braces enter and exit micro assembly
-def t_INITIAL_LBRACE(t):
+def t_header_LBRACE(t):
     r'\{'
-    t.lexer.push_state('asm')
+    t.lexer.pop_state()
     return t
 
 def t_asm_RBRACE(t):
@@ -262,11 +273,6 @@ def t_asm_RBRACE(t):
     t.lexer.pop_state()
     return t
 
-# At the top level, keep track of newlines only for line counting.
-def t_INITIAL_NEWLINE(t):
-    r'\n+'
-    t.lineno += t.value.count('\n')
-
 # In the micro assembler, do line counting but also return a token. The
 # token is needed by the parser to detect the end of a statement.
 def t_asm_NEWLINE(t):
@@ -287,6 +293,11 @@ def t_params_SEMI(t):
     t.lexer.pop_state()
     return t
 
+# Unless handled specially above, track newlines only for line counting.
+def t_ANY_NEWLINE(t):
+    r'\n+'
+    t.lineno += t.value.count('\n')
+
 # Basic regular expressions to pick out simple tokens
 t_ANY_LPAREN = r'\('
 t_ANY_RPAREN = r'\)'