Break runtime into different C file.

.gitignore

@@ -1,6 +1,7 @@
 tmp.lib
 main.s
 platform.s
+runtime.s
 *.o
 *.dbg
 *.map

Makefile

@@ -17,14 +17,17 @@ $(ROM): a.out
 run: $(ROM)
 	$(APPLE2E) -map main.map $(ROM)
 
-a.out: main.o interrupt.o vectors.o exporter.o platform.o apple2rom.cfg $(LIB)
-	$(CC65)/ld65 -C apple2rom.cfg -m main.map --dbgfile main.dbg interrupt.o vectors.o exporter.o platform.o main.o $(LIB)
+a.out: main.o interrupt.o vectors.o exporter.o platform.o runtime.o apple2rom.cfg $(LIB)
+	$(CC65)/ld65 -C apple2rom.cfg -m main.map --dbgfile main.dbg interrupt.o vectors.o exporter.o platform.o runtime.o main.o $(LIB)
 	awk -f rom_usage.awk < main.map
 
 clean:
-	rm -f *.o *.lst a.out platform.s main.s $(LIB) tmp.lib
+	rm -f *.o *.lst a.out platform.s runtime.s main.s $(LIB) tmp.lib
 
-main.s: main.c exporter.h platform.h
+main.s: main.c exporter.h platform.h runtime.h
+	$(CC65)/cc65 -t none -O --cpu $(CPU) $<
+
+runtime.s: runtime.c runtime.h
 	$(CC65)/cc65 -t none -O --cpu $(CPU) $<
 
 %.o: %.s

main.c

@@ -1,13 +1,10 @@
 #include "exporter.h"
 #include "platform.h"
+#include "runtime.h"
 
 uint8_t *title = "Apple IIa";
 uint8_t title_length = 9;
 
-#define CURSOR_GLYPH 127
-#define SCREEN_WIDTH 40
-#define SCREEN_STRIDE (3*SCREEN_WIDTH + 8)
-
 // 6502 instructions.
 #define I_CLC 0x18
 #define I_JSR 0x20
@@ -35,13 +32,6 @@ static uint8_t *TOKEN[] = {
 };
 static int16_t TOKEN_COUNT = sizeof(TOKEN)/sizeof(TOKEN[0]);
 
-// Location of cursor in logical screen space.
-uint16_t g_cursor_x = 0;
-uint16_t g_cursor_y = 0;
-// Whether the cursor is being displayed.
-uint16_t g_showing_cursor = 0;
-// Character at the cursor location.
-uint8_t g_cursor_ch = 0;
 uint8_t g_input_buffer[40];
 int16_t g_input_buffer_length = 0;
 
@@ -57,123 +47,6 @@ void (*g_compiled_function)() = (void (*)()) g_compiled;
 // - Nul.
 uint8_t g_program[1024];
 
-/**
- * Return the memory location of the cursor.
- */
-static volatile uint8_t *cursor_pos() {
-    int16_t block = g_cursor_y >> 3;
-    int16_t line = g_cursor_y & 0x07;
-
-    return TEXT_PAGE1_BASE + line*SCREEN_STRIDE + block*SCREEN_WIDTH + g_cursor_x;
-}
-
-/**
- * Shows the cursor. Safe to call if it's already showing.
- */
-static void show_cursor() {
-    if (!g_showing_cursor) {
-        volatile uint8_t *pos = cursor_pos();
-        g_cursor_ch = *pos;
-        *pos = CURSOR_GLYPH | 0x80;
-        g_showing_cursor = 1;
-    }
-}
-
-/**
- * Hides the cursor. Safe to call if it's not already shown.
- */
-static void hide_cursor() {
-    if (g_showing_cursor) {
-        volatile uint8_t *pos = cursor_pos();
-        *pos = g_cursor_ch;
-        g_showing_cursor = 0;
-    }
-}
-
-/**
- * Moves the cursor to the specified location, where X
- * is 0 to 39 inclusive, Y is 0 to 23 inclusive.
- */
-static void move_cursor(int16_t x, int16_t y) {
-    hide_cursor();
-    g_cursor_x = x;
-    g_cursor_y = y;
-}
-
-/**
- * Clear the screen with non-reversed spaces.
- */
-static void home() {
-    volatile uint8_t *p = TEXT_PAGE1_BASE;
-    uint8_t ch = ' ' | 0x80;
-    int16_t i;
-
-    // TODO: Could write these as words, not chars.
-    for (i = SCREEN_STRIDE*8; i >= 0; i--) {
-        *p++ = ch;
-    }
-
-    move_cursor(0, 0);
-}
-
-/**
- * Prints the character and advances the cursor. Handles newlines.
- */
-static void print_char(uint8_t c) {
-    volatile uint8_t *loc = cursor_pos();
-
-    if (c == '\n') {
-        // TODO: Scroll.
-        move_cursor(0, g_cursor_y + 1);
-    } else {
-        // Print character.
-        *loc = c | 0x80;
-        move_cursor(g_cursor_x + 1, g_cursor_y);
-    }
-}
-
-/**
- * Print a string at the cursor.
- */
-static void print(uint8_t *s) {
-    while (*s != '\0') {
-        print_char(*s++);
-    }
-}
-
-/**
- * Print an unsigned integer.
- */
-static void print_int(uint16_t i) {
-    // Is this the best way to do this? I've seen it done backwards, where
-    // digits are added to a buffer least significant digit first, then reversed,
-    // but this seems faster.
-    char printed = 0;
-    if (i >= 10000) {
-        int16_t r = i / 10000;
-        print_char('0' + r);
-        i -= r*10000;
-        printed = 1;
-    }
-    if (i >= 1000 || printed) {
-        int16_t r = i / 1000;
-        print_char('0' + r);
-        i -= r*1000;
-        printed = 1;
-    }
-    if (i >= 100 || printed) {
-        int16_t r = i / 100;
-        print_char('0' + r);
-        i -= r*100;
-        printed = 1;
-    }
-    if (i >= 10 || printed) {
-        int16_t r = i / 10;
-        print_char('0' + r);
-        i -= r*10;
-    }
-    print_char('0' + i);
-}
 
 /**
  * Copy a memory buffer. Source and destination may overlap.
@@ -265,13 +138,6 @@ static uint8_t *get_end_of_program(uint8_t *line) {
     return line + 2;
 }
 
-/**
- * Print a single newline.
- */
-static void print_newline() {
-    print_char('\n');
-}
-
 /**
  * List the stored program.
  */
@@ -306,14 +172,6 @@ static uint8_t *skip_over(uint8_t *a, uint8_t *b) {
     return *b == '\0' ? a : 0;
 }
 
-/**
- * Display a syntax error message.
- */
-static void syntax_error() {
-    print("\n?SYNTAX ERROR");
-    // No linefeed, assume prompt will do it.
-}
-
 /**
  * Add a function call to the compiled buffer.
  */

runtime.c

@@ -0,0 +1,147 @@
+
+#include "runtime.h"
+
+#define CURSOR_GLYPH 127
+#define SCREEN_WIDTH 40
+#define SCREEN_STRIDE (3*SCREEN_WIDTH + 8)
+
+// Location of cursor in logical screen space.
+uint16_t g_cursor_x = 0;
+uint16_t g_cursor_y = 0;
+// Whether the cursor is being displayed.
+uint16_t g_showing_cursor = 0;
+// Character at the cursor location.
+uint8_t g_cursor_ch = 0;
+
+/**
+ * Return the memory location of the cursor.
+ */
+volatile uint8_t *cursor_pos(void) {
+    int16_t block = g_cursor_y >> 3;
+    int16_t line = g_cursor_y & 0x07;
+
+    return TEXT_PAGE1_BASE + line*SCREEN_STRIDE + block*SCREEN_WIDTH + g_cursor_x;
+}
+
+/**
+ * Shows the cursor. Safe to call if it's already showing.
+ */
+void show_cursor(void) {
+    if (!g_showing_cursor) {
+        volatile uint8_t *pos = cursor_pos();
+        g_cursor_ch = *pos;
+        *pos = CURSOR_GLYPH | 0x80;
+        g_showing_cursor = 1;
+    }
+}
+
+/**
+ * Hides the cursor. Safe to call if it's not already shown.
+ */
+void hide_cursor(void) {
+    if (g_showing_cursor) {
+        volatile uint8_t *pos = cursor_pos();
+        *pos = g_cursor_ch;
+        g_showing_cursor = 0;
+    }
+}
+
+/**
+ * Moves the cursor to the specified location, where X
+ * is 0 to 39 inclusive, Y is 0 to 23 inclusive.
+ */
+void move_cursor(int16_t x, int16_t y) {
+    hide_cursor();
+    g_cursor_x = x;
+    g_cursor_y = y;
+}
+
+/**
+ * Clear the screen with non-reversed spaces.
+ */
+void home(void) {
+    volatile uint8_t *p = TEXT_PAGE1_BASE;
+    uint8_t ch = ' ' | 0x80;
+    int16_t i;
+
+    // TODO: Could write these as words, not chars.
+    for (i = SCREEN_STRIDE*8; i >= 0; i--) {
+        *p++ = ch;
+    }
+
+    move_cursor(0, 0);
+}
+
+/**
+ * Prints the character and advances the cursor. Handles newlines.
+ */
+void print_char(uint8_t c) {
+    volatile uint8_t *loc = cursor_pos();
+
+    if (c == '\n') {
+        // TODO: Scroll.
+        move_cursor(0, g_cursor_y + 1);
+    } else {
+        // Print character.
+        *loc = c | 0x80;
+        move_cursor(g_cursor_x + 1, g_cursor_y);
+    }
+}
+
+/**
+ * Print a string at the cursor.
+ */
+void print(uint8_t *s) {
+    while (*s != '\0') {
+        print_char(*s++);
+    }
+}
+
+/**
+ * Print an unsigned integer.
+ */
+void print_int(uint16_t i) {
+    // Is this the best way to do this? I've seen it done backwards, where
+    // digits are added to a buffer least significant digit first, then reversed,
+    // but this seems faster.
+    char printed = 0;
+    if (i >= 10000) {
+        int16_t r = i / 10000;
+        print_char('0' + r);
+        i -= r*10000;
+        printed = 1;
+    }
+    if (i >= 1000 || printed) {
+        int16_t r = i / 1000;
+        print_char('0' + r);
+        i -= r*1000;
+        printed = 1;
+    }
+    if (i >= 100 || printed) {
+        int16_t r = i / 100;
+        print_char('0' + r);
+        i -= r*100;
+        printed = 1;
+    }
+    if (i >= 10 || printed) {
+        int16_t r = i / 10;
+        print_char('0' + r);
+        i -= r*10;
+    }
+    print_char('0' + i);
+}
+
+/**
+ * Print a single newline.
+ */
+void print_newline(void) {
+    print_char('\n');
+}
+
+/**
+ * Display a syntax error message.
+ */
+void syntax_error(void) {
+    print("\n?SYNTAX ERROR");
+    // No linefeed, assume prompt will do it.
+}

runtime.h

@@ -0,0 +1,25 @@
+#ifndef __RUNTIME_H__
+#define __RUNTIME_H__
+
+#include "platform.h"
+
+extern uint16_t g_cursor_x;
+extern uint16_t g_cursor_y;
+extern uint16_t g_showing_cursor;
+extern uint8_t g_cursor_ch;
+
+volatile uint8_t *cursor_pos(void);
+void show_cursor(void);
+void hide_cursor(void);
+void move_cursor(int16_t x, int16_t y);
+
+void home(void);
+
+void print(uint8_t *s);
+void print_char(uint8_t c);
+void print_int(uint16_t i);
+void print_newline(void);
+
+void syntax_error(void);
+
+#endif // __RUNTIME_H__