From b33ebdfd1087bd1de038e23fd256ad5cc6576cfd Mon Sep 17 00:00:00 2001
From: Väinö Kauppila <vaino@vke.fi>
Date: Mon, 20 Apr 2026 15:11:08 +0300
Subject: 4K progmem

---
 fw/snake.c | 60 +++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 33 insertions(+), 27 deletions(-)

(limited to 'fw/snake.c')

diff --git a/fw/snake.c b/fw/snake.c
index a57d241..550bee2 100644
--- a/fw/snake.c
+++ b/fw/snake.c
@@ -8,7 +8,7 @@ __sfr __at(0x72) UART_STATUS;
 
 #define GRID_W       20
 #define GRID_H       10
-#define MAX_LEN      20
+#define MAX_LEN      10
 #define OVF_PER_FRAME 60
 
 #define DIR_UP    0
@@ -16,14 +16,14 @@ __sfr __at(0x72) UART_STATUS;
 #define DIR_LEFT  2
 #define DIR_RIGHT 3
 
-static uint8_t snake_x[MAX_LEN];
-static uint8_t snake_y[MAX_LEN];
-static uint8_t snake_len;
-static uint8_t direction;
-static uint8_t food_x;
-static uint8_t food_y;
-static uint8_t score;
-static volatile uint8_t ovf_count;
+static __near uint8_t snake_x[MAX_LEN];
+static __near uint8_t snake_y[MAX_LEN];
+static __near uint8_t snake_len;
+static __near uint8_t direction;
+static __near uint8_t food_x;
+static __near uint8_t food_y;
+static __near uint8_t score;
+static volatile __near uint8_t ovf_count;
 
 void isr(void) __interrupt(0) {
     if (INTCON & 0x04) {
@@ -65,21 +65,27 @@ static void handle_input(void) {
 }
 
 static void place_food(void) {
-    food_x = (ovf_count * 7 + 3) % GRID_W;
-    food_y = (ovf_count * 5 + 1) % GRID_H;
+    uint8_t x = ovf_count;
+    uint8_t y = ovf_count;
+    x += x; x += x; x += x; x -= ovf_count; x += 3;  /* x = ovf*7 + 3 */
+    y += y; y += y; y += ovf_count; y += 1;            /* y = ovf*5 + 1 */
+    while (x >= GRID_W) x -= GRID_W;
+    while (y >= GRID_H) y -= GRID_H;
+    food_x = x;
+    food_y = y;
 }
 
-static void print_uint8(uint8_t v) {
-    uint8_t started = 0;
-    if (v >= 200) { uart_send('2'); v -= 200; started = 1; }
-    else if (v >= 100) { uart_send('1'); v -= 100; started = 1; }
-    {
-        uint8_t t = '0';
-        while (v >= 10) { v -= 10; t++; }
-        if (started || t != '0') uart_send(t);
-    }
-    uart_send(v + '0');
-}
+/* static void print_uint8(uint8_t v) { */
+/*     uint8_t started = 0; */
+/*     if (v >= 200) { uart_send('2'); v -= 200; started = 1; } */
+/*     else if (v >= 100) { uart_send('1'); v -= 100; started = 1; } */
+/*     { */
+/*         uint8_t t = '0'; */
+/*         while (v >= 10) { v -= 10; t++; } */
+/*         if (started || t != '0') uart_send(t); */
+/*     } */
+/*     uart_send(v + '0'); */
+/* } */
 
 static void render(void) {
     uint8_t x, y, i;
@@ -115,8 +121,8 @@ static void render(void) {
     for (x = 0; x < GRID_W; x++) uart_send('-');
     uart_puts("+\r\n");
 
-    uart_puts("Score: ");
-    print_uint8(score);
+    /* uart_puts("Score: "); */
+    /* print_uint8(score); */
     uart_puts("   \r\n");
 }
 
@@ -186,9 +192,9 @@ void main(void) {
         }
 
         uart_puts("\x1B[2J\x1B[H");
-        uart_puts("GAME OVER  score: ");
-        print_uint8(score);
-        uart_puts("\r\npress any key\r\n");
+        /* uart_puts("GAME OVER  score: "); */
+        /* print_uint8(score); */
+        /* uart_puts("\r\npress any key\r\n"); */
         uart_getc();
     }
 }
-- 
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