autocommit for files dated 2014-11-17 20:13:34

[lice] / tests / cgoto.c

diff --git a/tests/cgoto.c b/tests/cgoto.c
new file mode 100644 (file)
index 0000000..b7c06a9
--- /dev/null
+++ b/tests/cgoto.c
@@ -0,0 +1,50 @@
+// labels as values (computed goto)
+
+int main(void) {
+    // implement a small dispatch table of instructions for a mini
+    // state machine, to test computed goto
+
+    // test state
+    int instruction_0_state = 0;
+    int instruction_1_state = 0;
+    int instruction_2_state = 0;
+
+    unsigned char bytecode[] = {0x01, 0x05, 0x01, 0x02, 0x02, 0x03};
+    unsigned char *pc        = bytecode;
+
+    void *dispatch[] = {
+        0,
+        &&instruction_0,
+        &&instruction_1,
+        &&instruction_2
+    };
+
+    #define DISPATCH(INDEX)      \
+        do {                     \
+            pc += (INDEX);       \
+            goto *dispatch[*pc]; \
+        } while (0)
+
+    // machine loop
+    do {
+
+        instruction_0:
+            instruction_0_state += *(pc + 1);
+            DISPATCH(2);
+
+        instruction_1:
+            instruction_1_state ++;
+            DISPATCH(1);
+
+        instruction_2:
+            instruction_2_state --;
+            break;
+
+    } while (1);
+
+    expecti(instruction_0_state, 7);
+    expecti(instruction_1_state, 1);
+    expecti(instruction_2_state, -1);
+
+    return 0;
+}