basic-m6502-cport-c99-more-generic.diff

patch against Microsoft BASIC M6502 C-port edition (https://github.com/YosAwed/M6502)

* remove nested funciton feature for generic C99 (OpenWatcom, clang)
* configurable virtual memory size for PEEK/POKE (mostly for 16bit environment)

to build 16bit MS-DOS executable with OpenWatcom v2 beta and GNUmake:
  make CC="owcc -b dos -mcmodel=l -mstack-size=4096"

diff --git a/basic.h b/basic.h
index d7e39e8..efe8406 100644
--- a/basic.h
+++ b/basic.h
@@ -1,6 +1,7 @@
 #ifndef BASIC_H
 #define BASIC_H
 
+#include <limits.h>
 #include <stdint.h>
 #include <stdbool.h>
 #include <stdio.h>
@@ -8,6 +9,15 @@
 #include <string.h>
 #include <math.h>
 
+#ifndef VIRTUAL_MEMORY_MAX
+// quick check 16 or 32+bits platform
+#if UINT_MAX <= 65535U
+#define VIRTUAL_MEMORY_MAX 4096
+#else
+#define VIRTUAL_MEMORY_MAX 65536
+#endif
+#endif
+
 // バージョン情報
 #define BASIC_VERSION_MAJOR 1
 #define BASIC_VERSION_MINOR 1
diff --git a/parser.c b/parser.c
index 55fe414..5304403 100644
--- a/parser.c
+++ b/parser.c
@@ -425,11 +425,17 @@ int basic_execute_line(basic_state_t* state, const char* line) {
     return 0;
 }
 
+
+#ifndef USE_NESTED_FUNCTIONS
+#define USE_NESTED_FUNCTIONS (defined(__GNUC__))
+#endif
+
 int cmd_print(basic_state_t* state, parser_state_t* parser) {
     bool trailing_semicolon = false;
     bool first = true;
     const int zone = 14; // Microsoft BASIC print zone width
 
+#if USE_NESTED_FUNCTIONS
     // local helper to output and track terminal column
     auto void put_text_and_track(const char* s) {
         if (!s) return;
@@ -444,6 +450,19 @@ int cmd_print(basic_state_t* state, parser_state_t* parser) {
         for (int i = 0; i < n; i++) putchar(' ');
         state->trmpos = (uint8_t)((state->trmpos + (unsigned)n) % 255);
     };
+#else
+  #define put_text_and_track(s) \
+    if ((s) != NULL) do { \
+        fputs(s, stdout); \
+        state->trmpos = (uint8_t)((state->trmpos + (unsigned)strlen(s)) % 255); \
+    } while(0)
+
+  #define put_spaces_and_track(n) \
+    if ((n) > 0) do { \
+        for (int i = 0; i < n; i++) putchar(' '); \
+        state->trmpos = (uint8_t)((state->trmpos + (unsigned)(n)) % 255); \
+    } while(0)
+#endif
     while (1) {
         // Allow bare EOL
         uint16_t pos0 = parser->position;
diff --git a/system_functions.c b/system_functions.c
index 840a0f0..d67e287 100644
--- a/system_functions.c
+++ b/system_functions.c
@@ -11,7 +11,7 @@ extern token_t get_next_token(basic_state_t* state, parser_state_t* parser);
 extern eval_result_t evaluate_expression(basic_state_t* state, parser_state_t* parser);
 
 // 仮想メモリ（元の6502メモリをシミュレート）
-static uint8_t virtual_memory[65536];
+static uint8_t virtual_memory[VIRTUAL_MEMORY_MAX];
 static bool memory_initialized = false;
 
 // メモリ初期化
@@ -25,6 +25,9 @@ void init_virtual_memory(void) {
 // PEEK関数 - メモリ読み取り
 numeric_value_t func_peek(uint16_t address) {
     init_virtual_memory();
+#if VIRTUAL_MEMORY_MAX < (UINT16_MAX)
+    if (address >= VIRTUAL_MEMORY_MAX) return double_to_numeric(255.0);
+#endif
     return double_to_numeric((double)virtual_memory[address]);
 }
 
@@ -52,6 +55,9 @@ int cmd_poke(basic_state_t* state, parser_state_t* parser_ptr) {
     
     uint16_t address = (uint16_t)numeric_to_double(addr_result.value.num);
     uint8_t value = (uint8_t)numeric_to_double(value_result.value.num);
+#if VIRTUAL_MEMORY_MAX < (UINT16_MAX)
+    if (address >= VIRTUAL_MEMORY_MAX) return 0;
+#endif
     
     init_virtual_memory();
     virtual_memory[address] = value;
@@ -327,11 +333,12 @@ int cmd_wait(basic_state_t* state, parser_state_t* parser_ptr) {
         // 条件を満たしている場合は即座に復帰
         return 0;
     }
-    
+
+#if defined(__unix__) || defined(__MINGW64_VERSION_MAJOR) || (defined(HAVE_NANOSLEEP) && (HAVE_NANOSLEEP))
     // 簡易実装：短時間待機
     struct timespec ts = {0, 10000000}; // 10ms
     nanosleep(&ts, NULL);
-    
+#endif
     return 0;
 }