compiler/devices: set initial time

artiq/compiler/lower_time.py

@@ -33,10 +33,10 @@ class _TimeLowerer(ast.NodeTransformer):
 		else:
 			return node
 
-def lower_time(stmts, ref_period):
+def lower_time(stmts, ref_period, initial_time):
 	transformer = _TimeLowerer(ref_period)
 	new_stmts = [transformer.visit(stmt) for stmt in stmts]
 	new_stmts.insert(0, ast.copy_location(
-		ast.Assign(targets=[ast.Name("now", ast.Store())], value=ast.Num(0)),
+		ast.Assign(targets=[ast.Name("now", ast.Store())], value=ast.Num(initial_time)),
 		stmts[0]))
 	stmts[:] = new_stmts

artiq/devices/core.py

@@ -17,7 +17,8 @@ class Core:
 		fold_constants(stmts)
 		unroll_loops(stmts, 50)
 		interleave(stmts)
-		lower_time(stmts, self.runtime_env.ref_period)
+		lower_time(stmts, self.runtime_env.ref_period,
+			getattr(self.runtime_env, "initial_time", 0))
 		fold_constants(stmts)
 
 		binary = get_runtime_binary(self.runtime_env, stmts)

artiq/devices/runtime.py

@@ -49,6 +49,7 @@ class LinkInterface:
 class Environment(LinkInterface):
 	def __init__(self, ref_period):
 		self.ref_period = ref_period
+		self.initial_time = 8000
 
 	def emit_object(self):
 		tm = lt.TargetMachine.new(triple="or1k", cpu="generic")

examples/ttl_test.py

@@ -7,7 +7,6 @@ class TTLTest(MPO):
 
 	@kernel
 	def run(self):
-		delay(10*us)
 		i = 0
 		while i < 100000:
 			with parallel: