diff --git a/c-test-arith/Makefile b/c-test-arith/Makefile
new file mode 100644
index 0000000..49d1aab
--- /dev/null
+++ b/c-test-arith/Makefile
@@ -0,0 +1 @@
+include ../common/common.mk
diff --git a/c-test-arith/main.c b/c-test-arith/main.c
new file mode 100644
index 0000000..e7bf177
--- /dev/null
+++ b/c-test-arith/main.c
@@ -0,0 +1,33 @@
+static void putc(int);
+
+int x;
+int y;
+int z;
+
+void _start(void)
+{
+	/* TODO: handle sp/fp init better -- separate crt0.S? */
+	asm ("law 03000");
+	asm ("dac 209");
+	asm ("law 04000");
+	asm ("dac 208");
+
+	x = 21;
+	y = 37;
+
+	z = x << 3;
+	if (z == 168)
+		putc(027);
+	
+	z = y >> 3;
+	if (z == 4)
+		putc(027);
+
+	asm ("hlt");
+	__builtin_unreachable();
+}
+
+static void putc(int c) {
+	asm ("lio %0" : : "r"(c));
+	asm ("tyo");
+}
diff --git a/pdp1-gcc b/pdp1-gcc
index 0be8d83..c52c05d 160000
--- a/pdp1-gcc
+++ b/pdp1-gcc
@@ -1 +1 @@
-Subproject commit 0be8d834a47ef2b399cdb453a68e6134b4fa2637
+Subproject commit c52c05d4f15a362e517379fba5d172e07660f3fe