Bug fixes

src/lexer.rs

@@ -444,9 +444,9 @@ mod tests {
 
     #[test]
     fn test_float_literal_decimal() {
-        let mut lexer = Lexer::new("X = 3.14159");
+        let mut lexer = Lexer::new("X = 1.23456");
         let tokens = lexer.tokenize().unwrap();
-        assert_eq!(tokens[2], Token::Float(3.14159));
+        assert_eq!(tokens[2], Token::Float(1.23456));
     }
 
     #[test]
@@ -783,13 +783,13 @@ mod tests {
 
     #[test]
     fn test_function_call() {
-        let mut lexer = Lexer::new("X = SIN(3.14) + COS(0)");
+        let mut lexer = Lexer::new("X = SIN(1.23) + COS(0)");
         let tokens = lexer.tokenize().unwrap();
         assert_eq!(tokens[0], Token::Ident("X".to_string()));
         assert_eq!(tokens[1], Token::Eq);
         assert_eq!(tokens[2], Token::Ident("SIN".to_string()));
         assert_eq!(tokens[3], Token::LParen);
-        assert_eq!(tokens[4], Token::Float(3.14));
+        assert_eq!(tokens[4], Token::Float(1.23));
         assert_eq!(tokens[5], Token::RParen);
         assert_eq!(tokens[6], Token::Plus);
         assert_eq!(tokens[7], Token::Ident("COS".to_string()));

src/runtime/sysv/data_defs.s

@@ -12,3 +12,4 @@ _chr_buf: .skip 2
 _str_buf: .skip 64
 _rng_state: .quad 0x12345678DEADBEEF
 _cls_seq: .asciz "\033[2J\033[H"
+_gosub_overflow_msg: .asciz "Error: GOSUB stack overflow\n"

src/runtime/sysv/print.s

@@ -130,3 +130,22 @@ _rt_print_float:
 .Lprint_float_done:
     leave
     ret
+
+# ------------------------------------------------------------------------------
+# _rt_gosub_overflow - Handle GOSUB stack overflow error
+# ------------------------------------------------------------------------------
+# Called when the GOSUB return stack is exhausted. Prints an error message
+# and terminates the program with exit code 1.
+#
+# Arguments: none
+# Returns: never (calls exit)
+# ------------------------------------------------------------------------------
+.globl _rt_gosub_overflow
+_rt_gosub_overflow:
+    push rbp
+    mov rbp, rsp
+    lea rdi, [rip + _gosub_overflow_msg]
+    xor eax, eax
+    call {libc}printf
+    mov edi, 1              # exit code 1
+    call {libc}exit

src/runtime/win64-native/data_defs.s

@@ -15,3 +15,7 @@
 _fmt_int: .asciz "%lld"
 _fmt_float: .asciz "%g"
 
+# Error messages
+_gosub_overflow_msg: .ascii "Error: GOSUB stack overflow\r\n"
+.equ _gosub_overflow_msg_len, 30
+

src/runtime/win64-native/print.s

@@ -178,3 +178,33 @@ _rt_print_float:
 
     leave
     ret
+
+# ------------------------------------------------------------------------------
+# _rt_gosub_overflow - Handle GOSUB stack overflow error
+# ------------------------------------------------------------------------------
+# Called when the GOSUB return stack is exhausted. Prints an error message
+# and terminates the program with exit code 1.
+#
+# Arguments: none
+# Returns: never (calls ExitProcess)
+# ------------------------------------------------------------------------------
+.globl _rt_gosub_overflow
+_rt_gosub_overflow:
+    push rbp
+    mov rbp, rsp
+    sub rsp, 48
+
+    # Get stdout handle
+    lea rax, [rip + _stdout_handle]
+    mov rcx, [rax]
+
+    # WriteFile(handle, message, length, &bytesWritten, NULL)
+    lea rdx, [rip + _gosub_overflow_msg]
+    mov r8, _gosub_overflow_msg_len
+    lea r9, [rip + _bytes_written]
+    mov QWORD PTR [rsp + 32], 0
+    call WriteFile
+
+    # ExitProcess(1)
+    mov ecx, 1
+    call ExitProcess