try fix the snake bug

1 files changed, 61 insertions, 26 deletions

diff --git a/fw/snake.c b/fw/snake.c
index 48ee417..e99802b 100644
--- a/fw/snake.c
+++ b/fw/snake.c
@@ -24,7 +24,6 @@ static __near uint8_t food_x;
 static __near uint8_t food_y;
 static __near uint8_t score;
 static volatile __near uint8_t ovf_count;
-static __near uint8_t input_state;  /* 0=idle, 1=got ESC, 2=got ESC+[ */
 
 void isr(void) __interrupt(0) {
     if (INTCON & 0x04) {
@@ -42,36 +41,72 @@ static void uart_puts(const char *s) {
     while (*s) uart_send((uint8_t)*s++);
 }
 
+// return 0 if EMPTY
 static uint8_t uart_recv(void) {
-    if (UART_STATUS & 0x02) // empty
+    if (UART_STATUS & 0b00000010) // empty
         return 0;
     return UART_RX;
 }
 
-/* Non-blocking state machine — drains the whole FIFO each frame.
- * Handles both ESC [ x (CSI) and ESC O x (SS3) cursor key modes.
- * Never blocks, so a stray ESC can't freeze the game. */
-static void handle_input(void) {
+/* /\* Non-blocking state machine — drains the whole FIFO each frame. */
+/*  * Handles both ESC [ x (CSI) and ESC O x (SS3) cursor key modes. */
+/*  * Never blocks, so a stray ESC can't freeze the game. *\/ */
+/* static void handle_input(void) { */
+/* 	uint8_t c; */
+/* 	while (1) { */
+/* 		c = uart_recv(); */
+/* 		if (c == 0) { */
+/* 			return; */
+/* 		}           */
+/* 		switch (input_state) { */
+/* 		case 0: */
+/* 			input_state = (c == 0x1B) ? 1 : 0; */
+/* 			break; */
+/* 		case 1: */
+/* 			input_state = (c == '[' || c == 'O') ? 2 : 0; */
+/* 			break; */
+/* 		case 2: */
+/* 			switch (c) { */
+/* 			case 'A': if (direction != DIR_DOWN)  direction = DIR_UP;    break; */
+/* 			case 'B': if (direction != DIR_UP)    direction = DIR_DOWN;  break; */
+/* 			case 'C': if (direction != DIR_LEFT)  direction = DIR_RIGHT; break; */
+/* 			case 'D': if (direction != DIR_RIGHT) direction = DIR_LEFT;  break; */
+/* 			} */
+/* 			input_state = 0; */
+/* 			break; */
+/*         } */
+/* 	} */
+/* } */
+
+static uint8_t __near esc_state = 0;
+
+/* drains UART FIFO fully each frame */
+static void handle_input(void)
+{
     uint8_t c;
-    for (int i = 0; i < 5; i++) {
-        c = uart_recv();
-        if (c == 0) return;
-        switch (input_state) {
-            case 0:
-                input_state = (c == 0x1B) ? 1 : 0;
-                break;
-            case 1:
-                input_state = (c == '[' || c == 'O') ? 2 : 0;
-                break;
-            case 2:
-                switch (c) {
-                    case 'A': if (direction != DIR_DOWN)  direction = DIR_UP;    break;
-                    case 'B': if (direction != DIR_UP)    direction = DIR_DOWN;  break;
-                    case 'C': if (direction != DIR_LEFT)  direction = DIR_RIGHT; break;
-                    case 'D': if (direction != DIR_RIGHT) direction = DIR_LEFT;  break;
-                }
-                input_state = 0;
-                break;
+
+    while (!(UART_STATUS & 0x02))   /* while not empty */
+    {
+        c = UART_RX;
+
+        if (esc_state == 0)
+        {
+            if (c == 0x1B) esc_state = 1;
+        }
+        else if (esc_state == 1)
+        {
+            esc_state = (c == '[' || c == 'O') ? 2 : 0;
+        }
+        else /* esc_state == 2 */
+        {
+            switch (c)
+            {
+                case 'A': if (direction != DIR_DOWN)  direction = DIR_UP;    break;
+                case 'B': if (direction != DIR_UP)    direction = DIR_DOWN;  break;
+                case 'C': if (direction != DIR_LEFT)  direction = DIR_RIGHT; break;
+                case 'D': if (direction != DIR_RIGHT) direction = DIR_LEFT;  break;
+            }
+            esc_state = 0;
         }
     }
 }
@@ -208,6 +243,6 @@ void main(void) {
         print_uint8(score);
         uart_puts("\r\npress any key\r\n");
         while (uart_recv() == 0);  /* wait for any byte */
-        input_state = 0;
+        esc_state = 0;
     }
 }