Apple-2-SW/apple2a
1
0
Fork 0
mirror of https://github.com/bradgrantham/apple2a.git synced 2024-05-31 19:41:36 +00:00
Code Issues Projects Releases Wiki Activity

Make code even more compact.

Browse Source
This commit is contained in:
Lawrence Kesteloot 2018-08-05 12:06:45 -07:00
parent f33d9ed8bd
commit a6ed83d669
1 changed files with 64 additions and 54 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

118
main.c
View File

@ -292,9 +292,10 @@ static uint8_t *skip_over(uint8_t *a, uint8_t *b) {
static void add_call(void *function) { static void add_call(void *function) {
uint16_t addr = (uint16_t) function; uint16_t addr = (uint16_t) function;
*g_c++ = I_JSR; g_c[0] = I_JSR;
*g_c++ = addr & 0xFF; g_c[1] = addr & 0xFF;
*g_c++ = addr >> 8; g_c[2] = addr >> 8;
g_c += 3;
} }
/** /**
@ -327,10 +328,11 @@ static uint16_t parse_uint16(uint8_t **s_ptr) {
* Generate code to put the value into AX. * Generate code to put the value into AX.
*/ */
static void compile_load_ax(uint16_t value) { static void compile_load_ax(uint16_t value) {
*g_c++ = I_LDX_IMM; g_c[0] = I_LDX_IMM;
*g_c++ = value >> 8; g_c[1] = value >> 8;
*g_c++ = I_LDA_IMM; g_c[2] = I_LDA_IMM;
*g_c++ = value & 0xFF; g_c[3] = value & 0xFF;
g_c += 4;
} }
/** /**
@ -512,10 +514,11 @@ static uint8_t *compile_expression(uint8_t *s) {
compile_load_ax(0); compile_load_ax(0);
} else { } else {
// Load from var. // Load from var.
*g_c++ = I_LDA_ZPG; g_c[0] = I_LDA_ZPG;
*g_c++ = var; g_c[1] = var;
*g_c++ = I_LDX_ZPG; g_c[2] = I_LDX_ZPG;
*g_c++ = var + 1; g_c[3] = var + 1;
g_c += 4;
} }
have_value_in_ax = 1; have_value_in_ax = 1;
} else { } else {
@ -788,10 +791,11 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Parse value. // Parse value.
s = compile_expression(s); s = compile_expression(s);
// Copy to var. // Copy to var.
*g_c++ = I_STA_ZPG; g_c[0] = I_STA_ZPG;
*g_c++ = var; g_c[1] = var;
*g_c++ = I_STX_ZPG; g_c[2] = I_STX_ZPG;
*g_c++ = var + 1; g_c[3] = var + 1;
g_c += 4;
} }
} }
} else if (*s == T_HOME) { } else if (*s == T_HOME) {
@ -815,20 +819,22 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Parse address. // Parse address.
s = compile_expression(s); s = compile_expression(s);
// Copy from AX to ptr1. // Copy from AX to ptr1.
*g_c++ = I_STA_ZPG; g_c[0] = I_STA_ZPG;
*g_c++ = (uint8_t) &ptr1; g_c[1] = (uint8_t) &ptr1;
*g_c++ = I_STX_ZPG; g_c[2] = I_STX_ZPG;
*g_c++ = (uint8_t) &ptr1 + 1; g_c[3] = (uint8_t) &ptr1 + 1;
g_c += 4;
if (*s != ',') { if (*s != ',') {
error = 1; error = 1;
} else { } else {
s++; s++;
// Parse value. LSB is in A. // Parse value. LSB is in A.
s = compile_expression(s); s = compile_expression(s);
*g_c++ = I_LDY_IMM; // Zero out Y. g_c[0] = I_LDY_IMM; // Zero out Y.
*g_c++ = 0; g_c[1] = 0;
*g_c++ = I_STA_IND_Y; // Store at *ptr1. g_c[2] = I_STA_IND_Y; // Store at *ptr1.
*g_c++ = (uint8_t) &ptr1; g_c[3] = (uint8_t) &ptr1;
g_c += 4;
} }
} else if (*s == T_GOTO) { } else if (*s == T_GOTO) {
s += 1; s += 1;
@ -849,9 +855,10 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
} }
} }
*g_c++ = I_JMP_ABS; g_c[0] = I_JMP_ABS;
*g_c++ = addr & 0xFF; g_c[1] = addr & 0xFF;
*g_c++ = addr >> 8; g_c[2] = addr >> 8;
g_c += 3;
} }
} else if (*s == T_IF) { } else if (*s == T_IF) {
// Save where we are in case we need to roll back. // Save where we are in case we need to roll back.
@ -861,18 +868,20 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// Parse conditional expression. // Parse conditional expression.
s = compile_expression(s); s = compile_expression(s);
// Check if AX is zero. Or the two bytes together, through the zero page. // Check if AX is zero. Or the two bytes together, through the zero page.
*g_c++ = I_STX_ZPG; g_c[0] = I_STX_ZPG;
*g_c++ = (uint8_t) &tmp1; g_c[1] = (uint8_t) &tmp1;
*g_c++ = I_ORA_ZPG; g_c[2] = I_ORA_ZPG;
*g_c++ = (uint8_t) &tmp1; g_c[3] = (uint8_t) &tmp1;
// If so, skip to end of this line. // If so, skip to end of this line.
*g_c++ = I_BNE_REL; g_c[4] = I_BNE_REL;
*g_c++ = 3; // Skip over absolute jump. g_c[5] = 3; // Skip over absolute jump.
*g_c++ = I_JMP_ABS; g_c[6] = I_JMP_ABS;
g_c += 7;
// TODO Check for overflow of end_of_line_address: // TODO Check for overflow of end_of_line_address:
end_of_line_address[end_of_line_count++] = (uint8_t **) g_c; end_of_line_address[end_of_line_count++] = (uint8_t **) g_c;
*g_c++ = 0; // Address of next line. g_c[0] = 0; // Address of next line.
*g_c++ = 0; // Address of next line. g_c[1] = 0; // Address of next line.
g_c += 2;
if (*s == T_THEN) { if (*s == T_THEN) {
// Skip THEN and continue // Skip THEN and continue
@ -915,10 +924,11 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
s = compile_expression(s); s = compile_expression(s);
// Copy to var. // Copy to var.
*g_c++ = I_STA_ZPG; g_c[0] = I_STA_ZPG;
*g_c++ = var; g_c[1] = var;
*g_c++ = I_STX_ZPG; g_c[2] = I_STX_ZPG;
*g_c++ = var + 1; g_c[3] = var + 1;
g_c += 4;
if (*s == T_TO) { if (*s == T_TO) {
s += 1; s += 1;
@ -945,10 +955,9 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// there would mess up how we fill it in below. Inline // there would mess up how we fill it in below. Inline
// it here so we have control over that. // it here so we have control over that.
loop_top_addr_addr = g_c; loop_top_addr_addr = g_c;
*g_c++ = I_LDX_IMM; g_c[0] = I_LDX_IMM;
g_c++; g_c[2] = I_LDA_IMM;
*g_c++ = I_LDA_IMM; g_c += 4;
g_c++;
add_call(for_statement); add_call(for_statement);
error = 0; error = 0;
@ -991,20 +1000,21 @@ static void compile_buffer(uint8_t *buffer, uint16_t line_number) {
// to if we're looping, or 0 if we're not. // 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. // Copy from AX to ptr1. We must save it because checking it destroys it.
*g_c++ = I_STA_ZPG; g_c[0] = I_STA_ZPG;
*g_c++ = (uint8_t) &ptr1; g_c[1] = (uint8_t) &ptr1;
*g_c++ = I_STX_ZPG; g_c[2] = I_STX_ZPG;
*g_c++ = (uint8_t) &ptr1 + 1; g_c[3] = (uint8_t) &ptr1 + 1;
// Check if AX is zero. Destroys AX. // Check if AX is zero. Destroys AX.
*g_c++ = I_ORA_ZPG; g_c[4] = I_ORA_ZPG;
*g_c++ = (uint8_t) &ptr1 + 1; // OR X into A. g_c[5] = (uint8_t) &ptr1 + 1; // OR X into A.
// If zero, skip over jump. // If zero, skip over jump.
*g_c++ = I_BEQ_REL; g_c[6] = I_BEQ_REL;
*g_c++ = 3; // Skip over indirect jump. g_c[7] = 3; // Skip over indirect jump.
// Jump to top of loop, indirectly through ptr1, which has the address. // Jump to top of loop, indirectly through ptr1, which has the address.
*g_c++ = I_JMP_IND; g_c[8] = I_JMP_IND;
*g_c++ = (uint8_t) &ptr1 & 0x0F; g_c[9] = (uint8_t) &ptr1 & 0x0F;
*g_c++ = (uint8_t) &ptr1 >> 8; g_c[10] = (uint8_t) &ptr1 >> 8;
g_c += 11;
} else if (*s == T_GR) { } else if (*s == T_GR) {
s += 1; s += 1;
add_call(gr_statement); add_call(gr_statement);