/*
* (c) 2019 Aaron Taylor <ataylor at subgeniuskitty dot com>
- * All rights reserved.
+ * See LICENSE.txt file for copyright and license details.
*/
#include <stdio.h>
#include <stdint.h>
#include <sys/select.h>
#include <getopt.h>
+#include <termios.h>
#define VERSION 1
-#define STACKSIZE 1024
-#define HEAPSIZE 1024
-#define RETURNSTACKSIZE 1024
+#define HEAPSIZE 65536 /* Size of heap in words */
+#define DATASTACKSIZE 65536 /* Size of stack in words */
+#define RETURNSTACKSIZE 65536 /* Max subroutine call depth */
void
print_usage(char ** argv)
{
- printf( "Whitespace Interpreter v%d (www.subgeniuskitty.com)\n"
+ printf( "VVhitespace Interpreter v%d (www.subgeniuskitty.com)\n"
"Usage: %s -i <file>\n"
" -h Help (prints this message)\n"
- " -i <file> Specify a Whitespace source file to interpret.\n"
+ " -i <file> Specify a VVhitespace source file to interpret.\n"
, VERSION, argv[0]
);
}
return 1;
}
+void
+set_terminal_mode(void)
+{
+ struct termios options;
+ tcgetattr(STDIN_FILENO, &options);
+ /* Create a cbreak-like environment through the following options. */
+ options.c_lflag &= ~ECHO; /* Disable echoing of input characters. */
+ options.c_lflag &= ~ICANON; /* Disable cooked/line-oriented mode. */
+ options.c_cc[VMIN] = 1;
+ options.c_cc[VTIME] = 0;
+ tcsetattr(STDIN_FILENO, TCSANOW, &options);
+}
+
+void
+unset_terminal_mode(void)
+{
+ struct termios options;
+ tcgetattr(STDIN_FILENO, &options);
+ /* Undo the changes made in set_terminal_mode(). */
+ options.c_lflag |= ECHO; /* Enable echoing of input characters. */
+ options.c_lflag |= ICANON; /* Enable cooked/line-oriented mode. */
+ options.c_cc[VMIN] = 1; /* Default value from /usr/src/sys/sys/ttydefaults.h */
+ options.c_cc[VTIME] = 0; /* Default value from /usr/src/sys/sys/ttydefaults.h */
+ tcsetattr(STDIN_FILENO, TCSANOW, &options);
+}
+
void
ws_die(size_t * pc, char * msg)
{
- printf("\n");
printf("SIM_ERROR @ PC %lu: %s\n", *pc, msg);
fflush(stdout);
+ unset_terminal_mode();
exit(EXIT_FAILURE);
}
void
-stack_push(int32_t ** sp, int32_t word)
+stack_push(int64_t ** sp, int64_t word)
{
*((*sp)++) = word;
}
-int32_t
-stack_pop(int32_t ** sp)
+int64_t
+stack_pop(int64_t ** sp)
{
return *(--(*sp));
}
-int32_t
-stack_peek(int32_t ** sp, size_t offset)
+int64_t
+stack_peek(int64_t ** sp, size_t offset)
/* offset=0 peeks TOS, offset=1 peeks NOS, etc. */
{
return *((*sp)-offset-1);
return code[(*pc)++];
}
+/*
+ * In addition to returning the parsed label, this function advances the PC to
+ * the next instruction.
+ */
uint16_t
parse_label(uint8_t * code, size_t * pc)
{
uint8_t c;
while ((c = code[(*pc)++]) != '\n') {
label = label << 1;
- if (c == ' ') label++;
+ if (c == '\t') label++;
}
return label;
}
+uint16_t
+check_label(size_t * labels, uint16_t label, size_t * pc)
+{
+ if (!labels[label]) {
+ fprintf(stderr, "Trying to process label 0x%X.\n", label);
+ ws_die(pc, "uninitialized label (forgot an include?)");
+ }
+ return label;
+}
+
+void
+populate_labels(size_t * labels, uint8_t * code, size_t code_size)
+{
+ size_t cp = 0;
+ while (cp <= code_size) {
+ if (code[cp++] == '\v') {
+ uint16_t temp_label = parse_label(code, &cp);
+ labels[temp_label] = cp;
+ }
+ }
+}
+
void
-process_imp_stack(uint8_t * code, size_t * pc, int32_t ** sp)
+process_imp_stack(uint8_t * code, size_t * pc, int64_t ** sp)
{
switch (next_code_byte(code,pc)) {
case ' ':
/* Push number onto TOS. */
{
/* First, pick off the sign */
- int32_t sign = 0;
+ int64_t sign = 0;
switch (next_code_byte(code,pc)) {
case ' ' : sign = 1; break;
case '\t': sign = -1; break;
- case '\n': ws_die(pc, "expected sign"); break;
+ default : ws_die(pc, "expected sign"); break;
}
/* Now, construct the number and push to TOS. */
/* I'm assuming the numbers are read MSb first. */
- int32_t temp, number = 0;
+ uint64_t number = 0; /* Unsigned to accomodate magnitude of most negative number. */
+ uint8_t temp;
while ((temp = next_code_byte(code,pc)) != '\n') {
+ if (temp == '\v') ws_die(pc, "non-binary digit in number");
number <<= 1;
if (temp == '\t') number++;
}
- stack_push(sp, number*sign);
+ /* Without temporarily casting to something >64-bit, the most negative */
+ /* number will overflow when performing 'number*sign'. Instead, we */
+ /* pick off the most negative number as a special case. */
+ if (number == (1ULL << 63) && sign == -1) {
+ /* C parses negative integer literals first as signed positive */
+ /* integer literals, then applying a unary negation operator. */
+ /* Thus, the most negative value is unreachable directly. */
+ int64_t number_temp = -9223372036854775807LL; /* First store -((2^63)-1) */
+ number_temp--; /* Now turn it into -(2^63) */
+ stack_push(sp, number_temp);
+ } else {
+ stack_push(sp, number*sign);
+ }
}
break;
case '\n':
/* Swap TOS and NOS. */
case '\t':
{
- int32_t t1 = stack_pop(sp);
- int32_t t2 = stack_pop(sp);
+ int64_t t1 = stack_pop(sp);
+ int64_t t2 = stack_pop(sp);
stack_push(sp, t1);
stack_push(sp, t2);
}
case '\n':
stack_pop(sp);
break;
+ default:
+ ws_die(pc, "malformed stack IMP");
+ break;
}
}
break;
- case '\t': ws_die(pc, "malformed stack IMP"); break;
+ default: ws_die(pc, "malformed stack IMP"); break;
}
}
void
-process_imp_arithmetic(uint8_t * code, size_t * pc, int32_t ** sp)
+process_imp_arithmetic(uint8_t * code, size_t * pc, int64_t ** sp)
{
- int32_t temp;
+ int64_t temp;
switch (next_code_byte(code,pc)) {
case ' ':
{
/* Multiplication */
stack_push(sp, stack_pop(sp)*stack_pop(sp));
break;
+ default:
+ ws_die(pc, "malformed arithmetic IMP");
+ break;
}
}
break;
case '\t':
/* Modulo */
temp = stack_pop(sp);
- stack_push(sp, stack_pop(sp)%temp);
+ stack_push(sp, llabs(stack_pop(sp) % llabs(temp)));
break;
- case '\n': ws_die(pc, "malformed arithmetic IMP"); break;
+ default: ws_die(pc, "malformed arithmetic IMP"); break;
}
}
break;
- case '\n': ws_die(pc, "malformed arithmetic IMP"); break;
+ default: ws_die(pc, "malformed arithmetic IMP"); break;
}
}
void
-process_imp_flowcontrol(uint8_t * code, size_t * pc, int32_t ** sp, uint32_t * labels,
- uint32_t ** rsp)
+process_imp_flowcontrol(uint8_t * code, size_t * pc, int64_t ** sp, size_t * labels,
+ size_t ** rsp)
{
+ size_t temp_pc;
switch (next_code_byte(code,pc)) {
case '\n':
/* Technically another LF is required but we ignore it. */
- printf("\n");
fflush(stdout);
+ unset_terminal_mode();
exit(EXIT_SUCCESS);
case ' ':
{
switch (next_code_byte(code,pc)) {
case ' ':
/* Mark a location in the program. */
- labels[parse_label(code, pc)] = *pc;
+ if (next_code_byte(code,pc) != '\v') ws_die(pc,"expected vtab, "
+ "perhaps a whitespace program, rather than vvhitespace?");
+ /* Jump to next instruction since labels were parsed during startup. */
+ parse_label(code, pc);
break;
case '\t':
/* Call a subroutine. */
+ temp_pc = labels[check_label(labels, parse_label(code, pc), pc)];
*((*rsp)++) = *pc;
- *pc = labels[parse_label(code, pc)];
+ *pc = temp_pc;
break;
case '\n':
/* Jump unconditionally to a label. */
- *pc = labels[parse_label(code, pc)];
+ *pc = labels[check_label(labels, parse_label(code, pc), pc)];
+ break;
+ default:
+ ws_die(pc, "malformed flow control IMP");
break;
}
}
switch (next_code_byte(code,pc)) {
case ' ':
/* Jump to a label if TOS == 0 */
- if (stack_peek(sp,0) == 0) *pc = labels[parse_label(code, pc)];
+ temp_pc = labels[check_label(labels, parse_label(code, pc), pc)];
+ if (stack_pop(sp) == 0) *pc = temp_pc;
break;
case '\t':
/* Jump to a label if TOS < 0. */
- if (stack_peek(sp,0) < 0) *pc = labels[parse_label(code, pc)];
+ temp_pc = labels[check_label(labels, parse_label(code, pc), pc)];
+ if (stack_pop(sp) < 0) *pc = temp_pc;
break;
case '\n':
/* Return from subroutine. */
*pc = *(--(*rsp));
break;
+ default:
+ ws_die(pc, "malformed flow control IMP");
+ break;
}
}
break;
+ default:
+ ws_die(pc, "malformed flow control IMP");
+ break;
}
}
void
-process_imp_heap(uint8_t * code, size_t * pc, int32_t ** sp, int32_t ** hp)
+process_imp_heap(uint8_t * code, size_t * pc, int64_t ** sp, int64_t ** hp)
{
switch (next_code_byte(code,pc)) {
- case ' ' : /* Store to heap */ *(*hp + *((*sp)-1)) = **sp; *sp -= 2; break;
- case '\t': /* Retrieve from heap */ **sp = *(*hp + **sp); break;
- case '\n': ws_die(pc, "malformed heap IMP"); break;
+ case ' ' :
+ /* Store to heap */
+ {
+ int64_t value = stack_pop(sp);
+ int64_t addr = stack_pop(sp);
+ *(*hp + addr) = value;
+ }
+ break;
+ case '\t':
+ /* Retrieve from heap */
+ stack_push(sp, *(*hp + stack_pop(sp)));
+ break;
+ default:
+ ws_die(pc, "malformed heap IMP");
+ break;
}
}
void
-process_imp_io(uint8_t * code, size_t * pc, int32_t ** sp, int32_t ** hp)
+process_imp_io(uint8_t * code, size_t * pc, int64_t ** sp, int64_t ** hp)
{
switch (next_code_byte(code,pc)) {
case ' ':
/* Output */
{
switch (next_code_byte(code,pc)) {
- case ' ' : /* Output character from TOS */ printf("%c", stack_pop(sp)); break;
- case '\t': /* Output number from TOS */ printf("%d", stack_pop(sp)); break;
- case '\n': ws_die(pc, "malformed output IMP"); break;
+ case ' ' : /* Output char from TOS */ printf("%c", (uint8_t) stack_pop(sp)); break;
+ case '\t': /* Output digit from TOS */ printf("%c", (uint8_t) stack_pop(sp)+'0'); break;
+ default : ws_die(pc, "malformed output IMP"); break;
}
fflush(stdout);
}
char c = getchar();
switch (next_code_byte(code,pc)) {
case '\t': /* Input digit */ c -= '0'; /* fallthrough */
- case ' ' : /* Input character */ *(*hp + *((*sp)--)) = c; break;
- case '\n': ws_die(pc, "malformed input IMP"); break;
+ case ' ' : /* Input character */ *(*hp + *(--(*sp))) = c; break;
+ default : ws_die(pc, "malformed input IMP"); break;
}
}
break;
- case '\n': ws_die(pc, "malformed i/o IMP"); break;
+ default: ws_die(pc, "malformed i/o IMP"); break;
}
}
-/* TODO: Continue cleanup here */
-
int
main(int argc, char ** argv)
{
}
}
if (input == NULL) {
- fprintf(stderr, "ERROR: Must specify a Whitespace source file with -f flag.\n");
+ fprintf(stderr, "ERROR: Must specify a VVhitespace source file with -f flag.\n");
print_usage(argv);
exit(EXIT_FAILURE);
}
/*
- * Read just the Whitespace source code into memory.
+ * Read just the VVhitespace source code into memory, stripping comment characters.
* We will use the array indices as addresses for the virtual PC when jumping to labels.
*/
size_t ws_code_size = 0;
uint8_t temp_byte;
while (fread(&temp_byte, 1, 1, input)) {
- if (temp_byte == ' ' || temp_byte == '\t' || temp_byte == '\n') ws_code_size++;
+ if (temp_byte == ' ' || temp_byte == '\t' || temp_byte == '\n' || temp_byte == '\v') {
+ ws_code_size++;
+ }
}
rewind(input);
uint8_t * ws_code_space = malloc(ws_code_size);
ws_code_size = 0;
while (fread(&temp_byte, 1, 1, input)) {
- if (temp_byte == ' ' || temp_byte == '\t' || temp_byte == '\n') ws_code_space[ws_code_size++] = temp_byte;
+ if (temp_byte == ' ' || temp_byte == '\t' || temp_byte == '\n' || temp_byte == '\v') {
+ ws_code_space[ws_code_size++] = temp_byte;
+ }
}
fclose(input);
/*
* Setup a stack and heap.
- * Assume a 32-bit word size.
*/
- int32_t * hp = malloc(HEAPSIZE*4);
- int32_t * sp = malloc(STACKSIZE*4);
+ int64_t * hp = malloc(HEAPSIZE*sizeof(int64_t));
+ int64_t * sp = malloc(DATASTACKSIZE*sizeof(int64_t));
/*
* Setup the return stack and the label array.
*/
- uint32_t * rsp = malloc(RETURNSTACKSIZE*4);
- uint32_t labels[65536];
+ size_t * rsp = malloc(RETURNSTACKSIZE*sizeof(size_t));
+ size_t labels[65536] = {0}; /* 65536 = 2^16 => Holds all possible labels. */
+ /* Default value of zero indicates an uninitialized label. */
+ populate_labels(labels, ws_code_space, ws_code_size);
/*
* Main Loop
*/
-
+ set_terminal_mode();
size_t pc = 0; /* Virtual program counter. Operates in the ws_code_space[] address space. */
while (1) {
if (pc >= ws_code_size) {
- fprintf(stderr, "SIM_ERROR: PC Overrun\n Requested PC: %lu\n Max Address: %lu\n", pc, ws_code_size-1);
+ fprintf(stderr, "SIM_ERROR: PC Overrun\n Requested PC: %lu\n Max Address: %lu\n",
+ pc, ws_code_size-1);
+ unset_terminal_mode();
exit(EXIT_FAILURE);
}
}
}
break;
+ default: ws_die(&pc, "unexpected byte"); break;
}
}
-
- printf("\n");
- printf("Program executed.\n");
-
- exit(EXIT_SUCCESS);
}