Change test bench

README.md

@@ -165,19 +165,18 @@ int fib(int n)      fib:                        Reserve stack frame for function
 
 1. Any non-zero value is NOT treated as logical truth by all ops.
    That is, the expression `0 == strcmp(ptr, "hello")` is not equivalent to `!strcmp(ptr, "hello")`.
-2. Global variable initialization is not supported. 
-   Therefore, you can not initialize a global such as `int i = [expr]`.
-3. Dereference is incomplete. Consider `int x = 5; int *ptr = &x;` and it is forbidden to use `*ptr`.
+2. Dereference is incomplete. Consider `int x = 5; int *ptr = &x;` and it is forbidden to use `*ptr`.
    However, it is valid to use `ptr[0]`, which behaves the same of `*ptr`.
-4. The support of varying number of function arguments is incomplete. No `<stdarg.h>` can be used.
+3. The support of varying number of function arguments is incomplete. No `<stdarg.h>` can be used.
    Alternatively, check the implementation `printf` in source `lib/c.c` for `var_arg`.
-5. The memory region allocated by `malloc` can not be released. In fact, there is no `free` function.
+4. The memory region allocated by `malloc` can not be released. In fact, there is no `free` function.
    Memory allocator should be introduced in embedded libc implementation.
-6. If you attempt to return values in `main` function, the value will not be reserved after the
+5. If you attempt to return values in `main` function, the value will not be reserved after the
    program exited. You have to modify the `return` statement to `exit` call. Check the test items in
    file `tests/driver.sh` for details.
-7. The C front-end is a bit dirty because there is no effective AST.
-8. No function pointer is supported.
+6. The C front-end is a bit dirty because there is no effective AST.
+7. No function pointer is supported.
+8. ELF lacks of .bss and .rodata section
 
 ## License
 

src/cfront.c

@@ -1314,12 +1314,17 @@ int read_global_assignment(char *token)
     var_t *var = find_global_var(token);
     if (var) {
         char buffer[10];
+        int isneg = 0;
         /* global initialization must be constant */
         /* TODO: support rvalue as expression e.g. int a = 3 + 2; */
+        if (lex_accept(T_minus))
+            isneg = 1;
         if (lex_peek(T_numeric, buffer))
             var->init_val = read_numeric_constant(buffer);
         else
             error("Invalid value after assignment");
+        if (isneg)
+            var->init_val = -1 * var->init_val;
         lex_expect(T_numeric);
         lex_expect(T_semicolon);
 

tests/driver.sh

@@ -247,6 +247,16 @@ int main() {
 }
 EOF
 
+# global initialization
+try_ 41 << EOF
+int a = 44;
+int b = -3;
+int main()
+{
+    exit(a + b);
+}
+EOF
+
 # conditional operator
 # expr 10 "1 ? 10 : 5"
 # expr 25 "0 ? 10 : 25"