Apple-2-SW/apple2a
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More efficient writing of machine code.

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This commit is contained in:
Lawrence Kesteloot 2018-08-05 12:00:59 -07:00
parent e143757158
commit f33d9ed8bd
3 changed files with 90 additions and 73 deletions
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8
Makefile
View File

@ -11,6 +11,8 @@ CPU = 6502
ROM = apple2a.rom
LIB = apple2rom.lib
CC65_FLAGS = -t none --cpu $(CPU)
$(ROM): a.out
(dd count=5 bs=4096 if=/dev/zero 2> /dev/null; cat a.out) > $(ROM)
@ -25,17 +27,17 @@ clean:
rm -f *.o *.lst a.out platform.s runtime.s main.s $(LIB) tmp.lib
main.s: main.c exporter.h platform.h runtime.h
$(CC65)/cc65 -t none -O --cpu $(CPU) $<
$(CC65)/cc65 $(CC65_FLAGS) -O $<
runtime.s: runtime.c runtime.h
$(CC65)/cc65 -t none -O --cpu $(CPU) $<
$(CC65)/cc65 $(CC65_FLAGS) -O $<
%.o: %.s
$(CC65)/ca65 -l $(<:.s=.lst) --cpu $(CPU) $<
# platform.c contains inline assembly and code that must not be optimized
platform.s: platform.c
$(CC65)/cc65 -t none --cpu $(CPU) $<
$(CC65)/cc65 $(CC65_FLAGS) $<
platform.o: platform.s
interrupt.o: interrupt.s

13
README.md
View File

@ -1,6 +1,17 @@
# Apple 2a
Custom ROM for the Apple 2e.
Custom ROM for the Apple 2e. Looks mostly like a real Apple 2e, but
when you type `RUN`, the code is compiled instead of interpreted.
Runs between 5 and 30 times faster.
Supported features: The classic way to enter programs with
line numbers, 16-bit integer variables, `HOME`, `PRINT`, `IF/THEN`,
`FOR/NEXT`, `GOTO`, low-res graphics (`GR`, `PLOT`, `COLOR=`, `TEXT`),
`POKE`, and basic arithmetic.
Not supported: Floating point, strings, `AND`, `OR`, `NOT`, negative
integers, high-res graphics, `DATA/READ/RESUME`, `GOSUB/RETURN/POP`,
keyboard input, and cassette I/O.
# Dependencies

142
main.c
View File

@ -161,7 +161,7 @@ int16_t g_input_buffer_length = 0;
// Compiled binary.
uint8_t g_compiled[1024];
int16_t g_compiled_length = 0;
uint8_t *g_c = g_compiled;
void (*g_compiled_function)() = (void (*)()) g_compiled;
// Stored program. Each line is:
@ -292,16 +292,16 @@ static uint8_t *skip_over(uint8_t *a, uint8_t *b) {
static void add_call(void *function) {
uint16_t addr = (uint16_t) function;
g_compiled[g_compiled_length++] = I_JSR;
g_compiled[g_compiled_length++] = addr & 0xFF;
g_compiled[g_compiled_length++] = addr >> 8;
*g_c++ = I_JSR;
*g_c++ = addr & 0xFF;
*g_c++ = addr >> 8;
}
/**
* Add a function return to the compiled buffer.
*/
static void add_return() {
g_compiled[g_compiled_length++] = I_RTS;
*g_c++ = I_RTS;
}
/**
@ -327,10 +327,10 @@ static uint16_t parse_uint16(uint8_t **s_ptr) {
* Generate code to put the value into AX.
*/
static void compile_load_ax(uint16_t value) {
g_compiled[g_compiled_length++] = I_LDX_IMM;
g_compiled[g_compiled_length++] = value >> 8;
g_compiled[g_compiled_length++] = I_LDA_IMM;
g_compiled[g_compiled_length++] = value & 0xFF;
*g_c++ = I_LDX_IMM;
*g_c++ = value >> 8;
*g_c++ = I_LDA_IMM;
*g_c++ = value & 0xFF;
}
/**
@ -512,10 +512,10 @@ static uint8_t *compile_expression(uint8_t *s) {
compile_load_ax(0);
} else {
// Load from var.
g_compiled[g_compiled_length++] = I_LDA_ZPG;
g_compiled[g_compiled_length++] = var;
g_compiled[g_compiled_length++] = I_LDX_ZPG;
g_compiled[g_compiled_length++] = var + 1;
*g_c++ = I_LDA_ZPG;
*g_c++ = var;
*g_c++ = I_LDX_ZPG;
*g_c++ = var + 1;
}
have_value_in_ax = 1;
} else {
@ -750,7 +750,7 @@ static uint8_t add_line_info(uint16_t line_number, uint8_t *code) {
* Call to configure the compilation step.
*/
static void set_up_compile(void) {
g_compiled_length = 0;
g_c = g_compiled;
g_line_info_count = 0;
g_forward_goto_count = 0;
}
@ -788,10 +788,10 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Parse value.
s = compile_expression(s);
// Copy to var.
g_compiled[g_compiled_length++] = I_STA_ZPG;
g_compiled[g_compiled_length++] = var;
g_compiled[g_compiled_length++] = I_STX_ZPG;
g_compiled[g_compiled_length++] = var + 1;
*g_c++ = I_STA_ZPG;
*g_c++ = var;
*g_c++ = I_STX_ZPG;
*g_c++ = var + 1;
}
}
} else if (*s == T_HOME) {
@ -815,20 +815,20 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Parse address.
s = compile_expression(s);
// Copy from AX to ptr1.
g_compiled[g_compiled_length++] = I_STA_ZPG;
g_compiled[g_compiled_length++] = (uint8_t) &ptr1;
g_compiled[g_compiled_length++] = I_STX_ZPG;
g_compiled[g_compiled_length++] = (uint8_t) &ptr1 + 1;
*g_c++ = I_STA_ZPG;
*g_c++ = (uint8_t) &ptr1;
*g_c++ = I_STX_ZPG;
*g_c++ = (uint8_t) &ptr1 + 1;
if (*s != ',') {
error = 1;
} else {
s++;
// Parse value. LSB is in A.
s = compile_expression(s);
g_compiled[g_compiled_length++] = I_LDY_IMM; // Zero out Y.
g_compiled[g_compiled_length++] = 0;
g_compiled[g_compiled_length++] = I_STA_IND_Y; // Store at *ptr1.
g_compiled[g_compiled_length++] = (uint8_t) &ptr1;
*g_c++ = I_LDY_IMM; // Zero out Y.
*g_c++ = 0;
*g_c++ = I_STA_IND_Y; // Store at *ptr1.
*g_c++ = (uint8_t) &ptr1;
}
} else if (*s == T_GOTO) {
s += 1;
@ -843,34 +843,36 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Line not found. Must be a forward GOTO. Record it
// and keep going.
uint8_t success = add_forward_goto(line_number, target_line_number,
&g_compiled[g_compiled_length]);
g_c);
if (!success) {
// TODO handle error.
}
}
g_compiled[g_compiled_length++] = I_JMP_ABS;
g_compiled[g_compiled_length++] = addr & 0xFF;
g_compiled[g_compiled_length++] = addr >> 8;
*g_c++ = I_JMP_ABS;
*g_c++ = addr & 0xFF;
*g_c++ = addr >> 8;
}
} else if (*s == T_IF) {
uint16_t saved_compiled_length = g_compiled_length;
// Save where we are in case we need to roll back.
uint8_t *saved_c = g_c;
s += 1;
// Parse conditional expression.
s = compile_expression(s);
// Check if AX is zero. Or the two bytes together, through the zero page.
g_compiled[g_compiled_length++] = I_STX_ZPG;
g_compiled[g_compiled_length++] = (uint8_t) &tmp1;
g_compiled[g_compiled_length++] = I_ORA_ZPG;
g_compiled[g_compiled_length++] = (uint8_t) &tmp1;
*g_c++ = I_STX_ZPG;
*g_c++ = (uint8_t) &tmp1;
*g_c++ = I_ORA_ZPG;
*g_c++ = (uint8_t) &tmp1;
// If so, skip to end of this line.
g_compiled[g_compiled_length++] = I_BNE_REL;
g_compiled[g_compiled_length++] = 3; // Skip over absolute jump.
g_compiled[g_compiled_length++] = I_JMP_ABS;
*g_c++ = I_BNE_REL;
*g_c++ = 3; // Skip over absolute jump.
*g_c++ = I_JMP_ABS;
// TODO Check for overflow of end_of_line_address:
end_of_line_address[end_of_line_count++] = (uint8_t **) &g_compiled[g_compiled_length];
g_compiled[g_compiled_length++] = 0; // Address of next line.
g_compiled[g_compiled_length++] = 0; // Address of next line.
end_of_line_address[end_of_line_count++] = (uint8_t **) g_c;
*g_c++ = 0; // Address of next line.
*g_c++ = 0; // Address of next line.
if (*s == T_THEN) {
// Skip THEN and continue
@ -881,7 +883,7 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
continue_statement = 1;
} else {
// Must be THEN or GOTO. Erase what we've done.
g_compiled_length = saved_compiled_length;
g_c = saved_c;
error = 1;
}
} else if (*s == T_FOR) {
@ -913,10 +915,10 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
s = compile_expression(s);
// Copy to var.
g_compiled[g_compiled_length++] = I_STA_ZPG;
g_compiled[g_compiled_length++] = var;
g_compiled[g_compiled_length++] = I_STX_ZPG;
g_compiled[g_compiled_length++] = var + 1;
*g_c++ = I_STA_ZPG;
*g_c++ = var;
*g_c++ = I_STX_ZPG;
*g_c++ = var + 1;
if (*s == T_TO) {
s += 1;
@ -942,11 +944,11 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Don't use compile_load_ax() here because a change
// there would mess up how we fill it in below. Inline
// it here so we have control over that.
loop_top_addr_addr = &g_compiled[g_compiled_length];
g_compiled[g_compiled_length++] = I_LDX_IMM;
g_compiled_length++;
g_compiled[g_compiled_length++] = I_LDA_IMM;
g_compiled_length++;
loop_top_addr_addr = g_c;
*g_c++ = I_LDX_IMM;
g_c++;
*g_c++ = I_LDA_IMM;
g_c++;
add_call(for_statement);
error = 0;
@ -956,7 +958,7 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
}
if (loop_top_addr_addr != 0) {
uint16_t loop_top_addr = (uint16_t) &g_compiled[g_compiled_length];
uint16_t loop_top_addr = (uint16_t) g_c;
loop_top_addr_addr[1] = loop_top_addr >> 8; // X
loop_top_addr_addr[3] = loop_top_addr & 0xFF; // A
}
@ -989,20 +991,20 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// to if we're looping, or 0 if we're not.
// Copy from AX to ptr1. We must save it because checking it destroys it.
g_compiled[g_compiled_length++] = I_STA_ZPG;
g_compiled[g_compiled_length++] = (uint8_t) &ptr1;
g_compiled[g_compiled_length++] = I_STX_ZPG;
g_compiled[g_compiled_length++] = (uint8_t) &ptr1 + 1;
*g_c++ = I_STA_ZPG;
*g_c++ = (uint8_t) &ptr1;
*g_c++ = I_STX_ZPG;
*g_c++ = (uint8_t) &ptr1 + 1;
// Check if AX is zero. Destroys AX.
g_compiled[g_compiled_length++] = I_ORA_ZPG;
g_compiled[g_compiled_length++] = (uint8_t) &ptr1 + 1; // OR X into A.
*g_c++ = I_ORA_ZPG;
*g_c++ = (uint8_t) &ptr1 + 1; // OR X into A.
// If zero, skip over jump.
g_compiled[g_compiled_length++] = I_BEQ_REL;
g_compiled[g_compiled_length++] = 3; // Skip over indirect jump.
*g_c++ = I_BEQ_REL;
*g_c++ = 3; // Skip over indirect jump.
// Jump to top of loop, indirectly through ptr1, which has the address.
g_compiled[g_compiled_length++] = I_JMP_IND;
g_compiled[g_compiled_length++] = (uint8_t) &ptr1 & 0x0F;
g_compiled[g_compiled_length++] = (uint8_t) &ptr1 >> 8;
*g_c++ = I_JMP_IND;
*g_c++ = (uint8_t) &ptr1 & 0x0F;
*g_c++ = (uint8_t) &ptr1 >> 8;
} else if (*s == T_GR) {
s += 1;
add_call(gr_statement);
@ -1062,7 +1064,7 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Fill in the places where we needed the address of the end of the line.
while (end_of_line_count > 0) {
*end_of_line_address[--end_of_line_count] = &g_compiled[g_compiled_length];
*end_of_line_address[--end_of_line_count] = g_c;
}
}
@ -1071,6 +1073,7 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
*/
static void complete_compile_and_execute(void) {
int i;
uint16_t compiled_length;
// Return from function.
add_return();
@ -1083,7 +1086,7 @@ static void complete_compile_and_execute(void) {
// jumps to error messages.
for (i = 0; i < g_forward_goto_count; i++) {
ForwardGoto *f = &g_forward_goto[i];
uint16_t addr = (uint16_t) &g_compiled[g_compiled_length];
uint16_t addr = (uint16_t) g_c;
// Jump to end of buffer.
f->jmp_address[1] = addr & 0xFF;
@ -1098,22 +1101,23 @@ static void complete_compile_and_execute(void) {
}
// Dump compiled buffer to the terminal.
compiled_length = g_c - g_compiled;
if (1) {
int i;
uint8_t *debug_port = (uint8_t *) 0xBFFE;
// Size of program (including initial address).
debug_port[0] = 2 + g_compiled_length;
debug_port[0] = 2 + compiled_length;
// Address of program start, little endian.
debug_port[1] = ((uint16_t) &g_compiled[0]) & 0xFF;
debug_port[1] = ((uint16_t) &g_compiled[0]) >> 8;
// Program bytes.
for (i = 0; i < g_compiled_length; i++) {
for (i = 0; i < compiled_length; i++) {
debug_port[1] = g_compiled[i];
}
}
if (g_compiled_length > sizeof(g_compiled)) {
if (compiled_length > sizeof(g_compiled)) {
// TODO: Check while adding bytes, not at the end.
print("\n?Binary length exceeded");
} else {
@ -1147,7 +1151,7 @@ static void compile_stored_program(void) {
while ((next_line = get_next_line(line)) != 0) {
uint16_t line_number = get_line_number(line);
uint8_t success = add_line_info(line_number, g_compiled + g_compiled_length);
uint8_t success = add_line_info(line_number, g_c);
// Compile just this line.
compile_buffer(line + 4, line_number);