1 files changed, 73 insertions, 0 deletions
diff --git a/tests/sysy_lvX/071_brainfk.sy b/tests/sysy_lvX/071_brainfk.sy
new file mode 100644
index 0000000..d1ee0c1
--- /dev/null
+++ b/tests/sysy_lvX/071_brainfk.sy
@@ -0,0 +1,73 @@
+/*
+a brainfuck interpreter
+reference: https://gist.github.com/maxcountryman/1699708
+*/
+
+// tape, input buffer, and read/write pointer
+const int TAPE_LEN = 65536, BUFFER_LEN = 32768;
+int tape[TAPE_LEN], program[BUFFER_LEN], ptr = 0;
+
+// read the input program
+void read_program() {
+  int i = 0, len = getint();
+  while (i < len) {
+    program[i] = getch();
+    i = i + 1;
+  }
+  program[i] = 0;
+}
+
+// interpret the input program
+void interpret(int input[]) {
+  int cur_char, loop, i = 0;
+  while (input[i]) {
+    cur_char = input[i];
+    if (cur_char == 62) {
+      // '>'
+      ptr = ptr + 1;
+    }
+    else if (cur_char == 60) {
+      // '<'
+      ptr = ptr - 1;
+    }
+    else if (cur_char == 43) {
+      // '+'
+      tape[ptr] = tape[ptr] + 1;
+    }
+    else if (cur_char == 45) {
+      // '-'
+      tape[ptr] = tape[ptr] - 1;
+    }
+    else if (cur_char == 46) {
+      // '.'
+      putch(tape[ptr]);
+    }
+    else if (cur_char == 44) {
+      // ','
+      tape[ptr] = getch();
+    }
+    else if (cur_char == 93 && tape[ptr]) {
+      // ']'
+      loop = 1;
+      while (loop > 0) {
+        i = i - 1;
+        cur_char = input[i];
+        if (cur_char == 91) {
+          // '['
+          loop = loop - 1;
+        }
+        else if (cur_char == 93) {
+          // ']'
+          loop = loop + 1;
+        }
+      }
+    }
+    i = i + 1;
+  }
+}
+
+int main() {
+  read_program();
+  interpret(program);
+  return 0;
+}