4K progmem

4 files changed, 60 insertions, 30 deletions

diff --git a/Makefile b/Makefile
index 633a174..d442655 100644
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,9 @@ $(BUILD):
 # -- Host-side C compilation (sdcc on host) --------------------------------------------
 
 $(BUILD)/%.hex: fw/%.c | $(BUILD)
-	cd $(BUILD) && sdcc --use-non-free -mpic14 -p16f84a $(CURDIR)/fw/$*.c
+	cd $(BUILD) && sdcc --use-non-free -mpic14 -p16f84a \
+		-Wl-s -Wl$(CURDIR)/fw/fpga_pic.lkr \
+		$(CURDIR)/fw/$*.c
 
 # program.hex is what the testbench loads at runtime
 $(BUILD)/program.hex: $(BUILD)/$(PROG).hex
diff --git a/fw/fpga_pic.lkr b/fw/fpga_pic.lkr
new file mode 100644
index 0000000..3fc716f
--- /dev/null
+++ b/fw/fpga_pic.lkr
@@ -0,0 +1,22 @@
+// Custom linker script for FPGA PIC implementation.
+// Code page extended to 4K words (real 16f84a only has 1K).
+// Bank 1 gprnobank left unprotected so UDL sections can be placed there.
+// UART/OW registers at 0x70-0x75 are left out of gprnobank.
+
+LIBPATH .
+
+CODEPAGE   NAME=page       START=0x0               END=0xFFF
+CODEPAGE   NAME=.idlocs    START=0x2000            END=0x2003         PROTECTED
+CODEPAGE   NAME=devid      START=0x2006            END=0x2006         PROTECTED
+CODEPAGE   NAME=.config    START=0x2007            END=0x2007         PROTECTED
+CODEPAGE   NAME=eedata     START=0x2100            END=0x213F         PROTECTED
+
+DATABANK   NAME=sfr0       START=0x0               END=0xB            PROTECTED
+DATABANK   NAME=sfr1       START=0x80              END=0x8B           PROTECTED
+
+SHAREBANK  NAME=gprnobank  START=0xC               END=0x6F
+SHAREBANK  NAME=gprnobank  START=0x8C              END=0xCF
+
+SECTION    NAME=PROG       ROM=page
+SECTION    NAME=IDLOCS     ROM=.idlocs
+SECTION    NAME=DEEPROM    ROM=eedata
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();
     }
 }
diff --git a/hex2rom.py b/hex2rom.py
index 291a702..3ddc5dc 100644
--- a/hex2rom.py
+++ b/hex2rom.py
@@ -9,7 +9,7 @@ Usage:
 import sys
 import argparse
 
-DEPTH = 1024
+DEPTH = 4096
 INST_BITS = 14
 
 def parse_ihex(path):
@@ -63,7 +63,7 @@ def render(words):
     lines.append('  process(clk)')
     lines.append('  begin')
     lines.append('    if rising_edge(clk) then')
-    lines.append('      data <= rom(to_integer(unsigned(addr(9 downto 0))));')
+    lines.append('      data <= rom(to_integer(unsigned(addr(11 downto 0))));')
     lines.append('    end if;')
     lines.append('  end process;')
     lines.append('end architecture rtl;')