Add POKE statement.
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2
Makefile
2
Makefile
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@ -24,7 +24,7 @@ a.out: main.o interrupt.o vectors.o exporter.o platform.o apple2rom.cfg $(LIB)
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clean:
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rm -f *.o *.lst a.out platform.s main.s $(LIB) tmp.lib
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main.s: main.c
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main.s: main.c exporter.h platform.h
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$(CC65)/cc65 -t none -O --cpu $(CPU) $<
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%.o: %.s
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@ -7,4 +7,7 @@ extern void pushax();
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extern void popax();
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extern void tosaddax();
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extern char ptr1;
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#pragma zpsym ("ptr1");
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#endif // __EXPORTER_H__
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@ -8,7 +8,9 @@
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.import pushax
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.import popax
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.import tosaddax
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.importzp ptr1
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.export _pushax := pushax
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.export _popax := popax
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.export _tosaddax := tosaddax
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.exportzp _ptr1 = ptr1
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47
main.c
47
main.c
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@ -9,8 +9,14 @@ uint8_t title_length = 9;
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#define SCREEN_STRIDE (3*SCREEN_WIDTH + 8)
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// 6502 instructions.
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#define I_CLC 0x18
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#define I_JSR 0x20
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#define I_SEC 0x38
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#define I_RTS 0x60
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#define I_STA_ZPG 0x85
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#define I_STX_ZPG 0x86
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#define I_STA_IND_Y 0x91
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#define I_LDY_IMM 0xA0
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#define I_LDX 0xA2
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#define I_LDA 0xA9
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@ -18,12 +24,14 @@ uint8_t title_length = 9;
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#define T_HOME 0x80
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#define T_PRINT 0x81
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#define T_LIST 0x82
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#define T_POKE 0x83
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// List of tokens. The token value is the index plus 0x80.
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static uint8_t *TOKEN[] = {
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"HOME",
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"PRINT",
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"LIST",
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"POKE",
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};
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static int16_t TOKEN_COUNT = sizeof(TOKEN)/sizeof(TOKEN[0]);
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@ -140,22 +148,26 @@ static void print_int(uint16_t i) {
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// Is this the best way to do this? I've seen it done backwards, where
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// digits are added to a buffer least significant digit first, then reversed,
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// but this seems faster.
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char printed = 0;
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if (i >= 10000) {
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int16_t r = i / 10000;
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print_char('0' + r);
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i -= r*10000;
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printed = 1;
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}
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if (i >= 1000) {
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if (i >= 1000 || printed) {
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int16_t r = i / 1000;
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print_char('0' + r);
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i -= r*1000;
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printed = 1;
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}
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if (i >= 100) {
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if (i >= 100 || printed) {
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int16_t r = i / 100;
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print_char('0' + r);
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i -= r*100;
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printed = 1;
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}
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if (i >= 10) {
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if (i >= 10 || printed) {
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int16_t r = i / 10;
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print_char('0' + r);
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i -= r*10;
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@ -501,6 +513,24 @@ static void process_input_buffer() {
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} else if (*s == T_LIST) {
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s += 1;
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add_call(list_statement);
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} else if (*s == T_POKE) {
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s += 1;
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// Parse address.
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s = compile_expression(s);
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// Copy from AX to ptr1.
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g_compiled[g_compiled_length++] = I_STA_ZPG;
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g_compiled[g_compiled_length++] = (uint8_t) &ptr1;
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g_compiled[g_compiled_length++] = I_STX_ZPG;
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g_compiled[g_compiled_length++] = (uint8_t) &ptr1 + 1;
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if (*s == ',') {
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s++;
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}
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// Parse value. LSB is in A.
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s = compile_expression(s);
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g_compiled[g_compiled_length++] = I_LDY_IMM;
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g_compiled[g_compiled_length++] = 0;
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g_compiled[g_compiled_length++] = I_STA_IND_Y;
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g_compiled[g_compiled_length++] = (uint8_t) &ptr1;
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} else {
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error = 1;
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}
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@ -527,6 +557,17 @@ static void process_input_buffer() {
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// Return from function.
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add_return();
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{
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int i;
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volatile uint8_t *debug_port = (uint8_t *) 0xBFFF;
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print("Compiled size: ");
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print_int(g_compiled_length);
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print_newline();
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for (i = 0; i < g_compiled_length; i++) {
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*debug_port = g_compiled[i];
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}
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}
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if (g_compiled_length > sizeof(g_compiled)) {
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// TODO: Check while adding bytes, not at the end.
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print("\n?Binary length exceeded");
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