From bff9474c3bf7159b16ca2caef6564a887934db43 Mon Sep 17 00:00:00 2001
From: Jose Rodriguez <boriel@gmail.com>
Date: Wed, 18 Oct 2017 22:59:06 +0200
Subject: [PATCH] add headerless mode

With the command line flag --headerless the compiler does not
generate neither ASM prologue nor epilogue.
---
 arch/zx48k/backend/__init__.py  |  9 ++++++++-
 tests/functional/headerless.asm | 17 +++++++++++++++++
 tests/functional/headerless.bas |  6 ++++++
 zxb.py                          |  3 +++
 4 files changed, 34 insertions(+), 1 deletion(-)
 create mode 100644 tests/functional/headerless.asm
 create mode 100644 tests/functional/headerless.bas

diff --git a/arch/zx48k/backend/__init__.py b/arch/zx48k/backend/__init__.py
index 8dba89589..9dd89269c 100644
--- a/arch/zx48k/backend/__init__.py
+++ b/arch/zx48k/backend/__init__.py
@@ -201,6 +201,8 @@ def init():
     OPTIONS.add_option('heap_start_label', str, 'ZXBASIC_MEM_HEAP')
     # Labels for HEAP SIZE (might not be used if not needed)
     OPTIONS.add_option('heap_size_label', str, 'ZXBASIC_HEAP_SIZE')
+    # Flag for headerless mode (No prologue / epilogue)
+    OPTIONS.add_option('headerless', bool, False)
 
 
 def new_ASMID():
@@ -402,6 +404,9 @@ def _end(ins):
     FLAG_end_emitted = True
 
     output.append('%s:' % END_LABEL)
+    if OPTIONS.headerless.value:
+        return output + ['ret']
+
     output.append('di')
     output.append('ld hl, (%s)' % CALL_BACK)
     output.append('ld sp, hl')
@@ -2164,7 +2169,9 @@ def __str__(self):
 # Program Start routine
 # -------------------------
 def emit_start():
-    output = []
+    output = list()
+    if OPTIONS.headerless.value:
+        return output
 
     output.append('org %s' % OPTIONS.org.value)
 
diff --git a/tests/functional/headerless.asm b/tests/functional/headerless.asm
new file mode 100644
index 000000000..b49ecb8b4
--- /dev/null
+++ b/tests/functional/headerless.asm
@@ -0,0 +1,17 @@
+	ld a, (_a)
+	inc a
+	ld (_a), a
+	ld hl, 0
+	ld b, h
+	ld c, l
+__END_PROGRAM:
+	ret
+
+ZXBASIC_USER_DATA:
+_a:
+	DEFB 02h
+	; Defines DATA END --> HEAP size is 0
+ZXBASIC_USER_DATA_END EQU ZXBASIC_MEM_HEAP
+	; Defines USER DATA Length in bytes
+ZXBASIC_USER_DATA_LEN EQU ZXBASIC_USER_DATA_END - ZXBASIC_USER_DATA
+	END
diff --git a/tests/functional/headerless.bas b/tests/functional/headerless.bas
new file mode 100644
index 000000000..06fe0c957
--- /dev/null
+++ b/tests/functional/headerless.bas
@@ -0,0 +1,6 @@
+REM a headerless (no prologuqe in ASM) program
+#pragma headerless=true
+
+DIM a as UByte = 2
+LET a = a + 1
+
diff --git a/zxb.py b/zxb.py
index 61bbb2de1..a49e97eff 100755
--- a/zxb.py
+++ b/zxb.py
@@ -141,6 +141,8 @@ def main(args=None):
                         help='Add colon separated list of directories to add to include path. e.g. -I dir1:dir2')
     parser.add_argument('--strict', action='store_true',
                         help='Enables strict mode. Force explicit type declaration')
+    parser.add_argument('--headerless', action='store_true',
+                        help='Header-less mode: omit asm prologue and epilogue')
     parser.add_argument('--version', action='version', version='%(prog)s {0}'.format(VERSION))
 
     options = parser.parse_args(args=args)
@@ -166,6 +168,7 @@ def main(args=None):
     OPTIONS.explicit.value = options.explicit
     OPTIONS.memory_map.value = options.memory_map
     OPTIONS.strict.value = options.strict
+    OPTIONS.headerless.value = options.headerless
 
     if options.defines:
         for i in options.defines: