[vvhitespace] / vv_interpreter.c

/*
 * (c) 2019 Aaron Taylor <ataylor at subgeniuskitty dot com>
 * All rights reserved.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdint.h>
#include <sys/select.h>
#include <getopt.h>

#define VERSION 1

#define STACKSIZE 1024
#define HEAPSIZE  1024
#define RETURNSTACKSIZE 1024

void
print_usage(char ** argv)
{
    printf( "VVhitespace Interpreter v%d (www.subgeniuskitty.com)\n"
            "Usage: %s -i <file>\n"
            "  -h         Help (prints this message)\n"
            "  -i <file>  Specify a VVhitespace source file to interpret.\n"
            , VERSION, argv[0]
    );
}

int
stdin_empty(void)
{
    fd_set read_fds;
    FD_ZERO(&read_fds);
    FD_SET(STDIN_FILENO, &read_fds);

    struct timeval timeout;
    timeout.tv_sec = 0;
    timeout.tv_usec = 0;

    int retval = select(1, &read_fds, NULL, NULL, &timeout);
    /* retval could be -1. Ignoring that for now. */
    if (retval > 0) return 0;
    return 1;
}

void
ws_die(size_t * pc, char * msg)
{
    printf("\n");
    printf("SIM_ERROR @ PC %lu: %s\n", *pc, msg);
    fflush(stdout);
    exit(EXIT_FAILURE);
}

void
stack_push(int32_t ** sp, int32_t word)
{
    *((*sp)++) = word;
}

int32_t
stack_pop(int32_t ** sp)
{
    return *(--(*sp));
}

int32_t
stack_peek(int32_t ** sp, size_t offset)
/* offset=0 peeks TOS, offset=1 peeks NOS, etc. */
{
    return *((*sp)-offset-1);
}

uint8_t
next_code_byte(uint8_t * code, size_t * pc)
{
    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)
{
    uint16_t label = 0;
    uint8_t c;
    while ((c = code[(*pc)++]) != '\n') {
        label = label << 1;
        if (c == ' ') label++;
    }
    // TODO: Where should I handle attempts to access an unitialized label?
    //       For now, leave it undefined in a nasal demon sense.
    return label;
}

void
populate_labels(uint32_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;
        }
        cp++;
    }
}

void
process_imp_stack(uint8_t * code, size_t * pc, int32_t ** sp)
{
    switch (next_code_byte(code,pc)) {
        case ' ':
            /* Push number onto TOS. */
            {
                /* First, pick off the sign */
                int32_t sign = 0;
                switch (next_code_byte(code,pc)) {
                    case ' ' :  sign = 1;                       break;
                    case '\t':  sign = -1;                      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;
                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);
            }
            break;
        case '\n':
            /* Stack sub-command */
            {
                switch (next_code_byte(code,pc)) {
                        /* Duplicate the TOS. */
                    case ' ':
                        stack_push(sp, stack_peek(sp,0));
                        break;
                        /* Swap TOS and NOS. */
                    case '\t':
                        {
                            int32_t t1 = stack_pop(sp);
                            int32_t t2 = stack_pop(sp);
                            stack_push(sp, t1);
                            stack_push(sp, t2);
                        }
                        break;
                        /* Discard TOS. */
                    case '\n':
                        stack_pop(sp);
                        break;
                    default:
                        ws_die(pc, "malformed stack IMP");
                        break;
                }
            }
            break;
        default: ws_die(pc, "malformed stack IMP"); break;
    }
}

void
process_imp_arithmetic(uint8_t * code, size_t * pc, int32_t ** sp)
{
    int32_t temp;
    switch (next_code_byte(code,pc)) {
        case ' ':
            {
                switch (next_code_byte(code,pc)) {
                    case ' ':
                        /* Addition */
                        stack_push(sp, stack_pop(sp)+stack_pop(sp));
                        break;
                    case '\t':
                        /* Subtraction */
                        temp = stack_pop(sp);
                        stack_push(sp, stack_pop(sp)-temp);
                        break;
                    case '\n':
                        /* Multiplication */
                        stack_push(sp, stack_pop(sp)*stack_pop(sp));
                        break;
                    default:
                        ws_die(pc, "malformed arithmetic IMP");
                        break;
                }
            }
            break;
        case '\t':
            {
                switch (next_code_byte(code,pc)) {
                    case ' ':
                        /* Division */
                        temp = stack_pop(sp);
                        stack_push(sp, stack_pop(sp)/temp);
                        break;
                    case '\t':
                        /* Modulo */
                        temp = stack_pop(sp);
                        stack_push(sp, stack_pop(sp)%temp);
                        break;
                    default: ws_die(pc, "malformed arithmetic IMP"); break;
                }
            }
            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)
{
    switch (next_code_byte(code,pc)) {
        case '\n':
            /* Technically another LF is required but we ignore it. */
            printf("\n");
            fflush(stdout);
            exit(EXIT_SUCCESS);
        case ' ':
            {
                switch (next_code_byte(code,pc)) {
                    case ' ':
                        /* Mark a location in the program. */
                        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. */
                        *((*rsp)++) = *pc;
                        *pc = labels[parse_label(code, pc)];
                        break;
                    case '\n':
                        /* Jump unconditionally to a label. */
                        *pc = labels[parse_label(code, pc)];
                        break;
                    default:
                        ws_die(pc, "malformed flow control IMP");
                        break;
                }
            }
            break;
        case '\t':
            {
                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)];
                        break;
                    case '\t':
                        /* Jump to a label if TOS < 0. */
                        if (stack_peek(sp,0) < 0) *pc = labels[parse_label(code, 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)
{
    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;
        default  : ws_die(pc, "malformed heap IMP");                              break;
    }
}

void
process_imp_io(uint8_t * code, size_t * pc, int32_t ** sp, int32_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;
                    default  : ws_die(pc, "malformed output IMP");                          break;
                }
                fflush(stdout);
            }
            break;
        case '\t':
            /* Input */
            {
                while (stdin_empty()) continue;
                char c = getchar();
                switch (next_code_byte(code,pc)) {
                    case '\t': /* Input digit     */ c -= '0';                /* fallthrough */
                    case ' ' : /* Input character */ *(*hp + *((*sp)--)) = c; break;
                    default  : ws_die(pc, "malformed input IMP");             break;
                }
            }
            break;
        default: ws_die(pc, "malformed i/o IMP"); break;
    }
}

int
main(int argc, char ** argv)
{
    /*
     * Process command line arguments
     */
    int c;
    FILE * input = NULL;
    while ((c = getopt(argc,argv,"i:h")) != -1) {
        switch (c) {
            case 'i':
                if ((input = fopen(optarg, "r")) == NULL) {
                    fprintf(stderr, "ERROR: %s: %s\n", optarg, strerror(errno));
                }
                break;
            case 'h':
                print_usage(argv);
                exit(EXIT_SUCCESS);
                break;
            default:
                break;
        }
    }
    if (input == NULL) {
        fprintf(stderr, "ERROR: Must specify a VVhitespace source file with -f flag.\n");
        print_usage(argv);
        exit(EXIT_FAILURE);
    }

    /*
     * Read just the VVhitespace source code into memory.
     * 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' || 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' || temp_byte == '\v') {
            ws_code_space[ws_code_size++] = temp_byte;
        }
    }
    fclose(input);

    /*
     * Setup a stack and heap.
     * Assume a 32-bit word size.
     */
    // TODO: Make everything 64-bit.
    int32_t * hp = malloc(HEAPSIZE*4);
    int32_t * sp = malloc(STACKSIZE*4);

    /* 
     * Setup the return stack and the label array.
     */
    uint32_t * rsp = malloc(RETURNSTACKSIZE*4);
    uint32_t labels[65536] = {0};
    populate_labels(labels, ws_code_space, ws_code_size);

    /*
     * Main Loop
     */

    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);
            exit(EXIT_FAILURE);
        }
// TODO: Have the SIGTERM signal handler and normal term point return the value
// on TOS so I can do rudimentary automated tests.

        /* Decode the IMPs */
        switch (ws_code_space[pc++]) {
            case ' ':
                /* Stack Manipulation */
                process_imp_stack(ws_code_space, &pc, &sp);
                break;
            case '\n':
                /* Flow Control */
                process_imp_flowcontrol(ws_code_space, &pc, &sp, labels, &rsp);
                break;
            case '\t':
                /* Arithmetic, Heap Access, or I/O */
                {
                    switch (ws_code_space[pc++]) {
                        case ' ':
                            /* Arithmetic */
                            process_imp_arithmetic(ws_code_space, &pc, &sp);
                            break;
                        case '\t':
                            /* Heap Access */
                            process_imp_heap(ws_code_space, &pc, &sp, &hp);
                            break;
                        case '\n':
                            /* I/O */
                            process_imp_io(ws_code_space, &pc, &sp, &hp);
                            break;
                    }
                }
                break;
            default: ws_die(&pc, "unexpected VTab"); break;
        }
    }

    printf("\n");
    printf("Program executed.\n");

    exit(EXIT_SUCCESS);
}
Commit	Line	Data
1adfc4f4 AT	1	/*
	2	* (c) 2019 Aaron Taylor <ataylor at subgeniuskitty dot com>
	3	* All rights reserved.
	4	*/
	5
	6	#include <stdio.h>
	7	#include <stdlib.h>
	8	#include <unistd.h>
	9	#include <string.h>
	10	#include <errno.h>
	11	#include <stdint.h>
	12	#include <sys/select.h>
	13	#include <getopt.h>
	14
	15	#define VERSION 1
	16
	17	#define STACKSIZE 1024
	18	#define HEAPSIZE 1024
	19	#define RETURNSTACKSIZE 1024
	20
	21	void
	22	print_usage(char ** argv)
	23	{
bf43fa3f	24	printf( "VVhitespace Interpreter v%d (www.subgeniuskitty.com)\n"
1adfc4f4 AT	25	"Usage: %s -i <file>\n"
1adfc4f4 AT	26	" -h Help (prints this message)\n"
bf43fa3f	27	" -i <file> Specify a VVhitespace source file to interpret.\n"
1adfc4f4 AT	28	, VERSION, argv[0]
	29	);
	30	}
	31
	32	int
	33	stdin_empty(void)
	34	{
	35	fd_set read_fds;
	36	FD_ZERO(&read_fds);
	37	FD_SET(STDIN_FILENO, &read_fds);
	38
	39	struct timeval timeout;
	40	timeout.tv_sec = 0;
	41	timeout.tv_usec = 0;
	42
	43	int retval = select(1, &read_fds, NULL, NULL, &timeout);
	44	/* retval could be -1. Ignoring that for now. */
	45	if (retval > 0) return 0;
	46	return 1;
	47	}
	48
	49	void
	50	ws_die(size_t * pc, char * msg)
	51	{
	52	printf("\n");
	53	printf("SIM_ERROR @ PC %lu: %s\n", *pc, msg);
	54	fflush(stdout);
	55	exit(EXIT_FAILURE);
	56	}
	57
	58	void
	59	stack_push(int32_t ** sp, int32_t word)
	60	{
	61	((sp)++) = word;
	62	}
	63
	64	int32_t
	65	stack_pop(int32_t ** sp)
	66	{
	67	return (--(sp));
	68	}
	69
	70	int32_t
	71	stack_peek(int32_t ** sp, size_t offset)
	72	/* offset=0 peeks TOS, offset=1 peeks NOS, etc. */
	73	{
	74	return ((sp)-offset-1);
	75	}
	76
	77	uint8_t
	78	next_code_byte(uint8_t * code, size_t * pc)
	79	{
	80	return code[(*pc)++];
	81	}
	82
9686c901 AT	83	/*
	84	* In addition to returning the parsed label, this function advances the PC to
	85	* the next instruction.
	86	*/
1adfc4f4 AT	87	uint16_t
	88	parse_label(uint8_t * code, size_t * pc)
	89	{
	90	uint16_t label = 0;
	91	uint8_t c;
	92	while ((c = code[(*pc)++]) != '\n') {
	93	label = label << 1;
	94	if (c == ' ') label++;
	95	}
9686c901 AT	96	// TODO: Where should I handle attempts to access an unitialized label?
9686c901 AT	97	// For now, leave it undefined in a nasal demon sense.
1adfc4f4 AT	98	return label;
	99	}
	100
bf43fa3f AT	101	void
	102	populate_labels(uint32_t * labels, uint8_t * code, size_t code_size)
	103	{
9686c901 AT	104	size_t cp = 0;
	105	while (cp <= code_size) {
	106	if (code[cp] == '\v') {
	107	uint16_t temp_label = parse_label(code, &cp);
	108	labels[temp_label] = cp;
	109	}
	110	cp++;
	111	}
bf43fa3f AT	112	}
bf43fa3f AT	113
1adfc4f4 AT	114	void
	115	process_imp_stack(uint8_t * code, size_t * pc, int32_t ** sp)
	116	{
	117	switch (next_code_byte(code,pc)) {
	118	case ' ':
	119	/* Push number onto TOS. */
	120	{
	121	/* First, pick off the sign */
	122	int32_t sign = 0;
	123	switch (next_code_byte(code,pc)) {
	124	case ' ' : sign = 1; break;
	125	case '\t': sign = -1; break;
bf43fa3f	126	default : ws_die(pc, "expected sign"); break;
1adfc4f4 AT	127	}
	128
	129	/* Now, construct the number and push to TOS. */
	130	/* I'm assuming the numbers are read MSb first. */
	131	int32_t temp, number = 0;
	132	while ((temp = next_code_byte(code,pc)) != '\n') {
bf43fa3f	133	if (temp == '\v') ws_die(pc, "non-binary digit in number");
1adfc4f4 AT	134	number <<= 1;
	135	if (temp == '\t') number++;
	136	}
	137	stack_push(sp, number*sign);
	138	}
	139	break;
	140	case '\n':
	141	/* Stack sub-command */
	142	{
	143	switch (next_code_byte(code,pc)) {
	144	/* Duplicate the TOS. */
	145	case ' ':
	146	stack_push(sp, stack_peek(sp,0));
	147	break;
	148	/* Swap TOS and NOS. */
	149	case '\t':
	150	{
	151	int32_t t1 = stack_pop(sp);
	152	int32_t t2 = stack_pop(sp);
	153	stack_push(sp, t1);
	154	stack_push(sp, t2);
	155	}
	156	break;
	157	/* Discard TOS. */
	158	case '\n':
	159	stack_pop(sp);
	160	break;
bf43fa3f AT	161	default:
	162	ws_die(pc, "malformed stack IMP");
	163	break;
1adfc4f4 AT	164	}
	165	}
	166	break;
bf43fa3f	167	default: ws_die(pc, "malformed stack IMP"); break;
1adfc4f4 AT	168	}
	169	}
	170
	171	void
	172	process_imp_arithmetic(uint8_t * code, size_t * pc, int32_t ** sp)
	173	{
	174	int32_t temp;
	175	switch (next_code_byte(code,pc)) {
	176	case ' ':
	177	{
	178	switch (next_code_byte(code,pc)) {
	179	case ' ':
	180	/* Addition */
	181	stack_push(sp, stack_pop(sp)+stack_pop(sp));
	182	break;
	183	case '\t':
	184	/* Subtraction */
	185	temp = stack_pop(sp);
	186	stack_push(sp, stack_pop(sp)-temp);
	187	break;
	188	case '\n':
	189	/* Multiplication */
	190	stack_push(sp, stack_pop(sp)*stack_pop(sp));
	191	break;
bf43fa3f AT	192	default:
	193	ws_die(pc, "malformed arithmetic IMP");
	194	break;
1adfc4f4 AT	195	}
	196	}
	197	break;
	198	case '\t':
	199	{
	200	switch (next_code_byte(code,pc)) {
	201	case ' ':
	202	/* Division */
	203	temp = stack_pop(sp);
	204	stack_push(sp, stack_pop(sp)/temp);
	205	break;
	206	case '\t':
	207	/* Modulo */
	208	temp = stack_pop(sp);
	209	stack_push(sp, stack_pop(sp)%temp);
	210	break;
bf43fa3f	211	default: ws_die(pc, "malformed arithmetic IMP"); break;
1adfc4f4 AT	212	}
	213	}
	214	break;
bf43fa3f	215	default: ws_die(pc, "malformed arithmetic IMP"); break;
1adfc4f4 AT	216	}
	217	}
	218
	219	void
	220	process_imp_flowcontrol(uint8_t * code, size_t * pc, int32_t ** sp, uint32_t * labels,
	221	uint32_t ** rsp)
	222	{
	223	switch (next_code_byte(code,pc)) {
	224	case '\n':
	225	/* Technically another LF is required but we ignore it. */
	226	printf("\n");
	227	fflush(stdout);
	228	exit(EXIT_SUCCESS);
	229	case ' ':
	230	{
	231	switch (next_code_byte(code,pc)) {
	232	case ' ':
	233	/* Mark a location in the program. */
9686c901 AT	234	if (next_code_byte(code,pc) != '\v') ws_die(pc,"expected vtab, "
	235	"perhaps a whitespace program, rather than vvhitespace?");
	236	/* Jump to next instruction since labels were parsed during startup. */
	237	parse_label( code, pc);
1adfc4f4 AT	238	break;
	239	case '\t':
	240	/* Call a subroutine. */
	241	((rsp)++) = *pc;
	242	*pc = labels[parse_label(code, pc)];
	243	break;
	244	case '\n':
	245	/* Jump unconditionally to a label. */
	246	*pc = labels[parse_label(code, pc)];
	247	break;
bf43fa3f AT	248	default:
	249	ws_die(pc, "malformed flow control IMP");
	250	break;
1adfc4f4 AT	251	}
	252	}
	253	break;
	254	case '\t':
	255	{
	256	switch (next_code_byte(code,pc)) {
	257	case ' ':
	258	/* Jump to a label if TOS == 0 */
	259	if (stack_peek(sp,0) == 0) *pc = labels[parse_label(code, pc)];
	260	break;
	261	case '\t':
	262	/* Jump to a label if TOS < 0. */
	263	if (stack_peek(sp,0) < 0) *pc = labels[parse_label(code, pc)];
	264	break;
	265	case '\n':
	266	/* Return from subroutine. */
	267	pc = (--(*rsp));
	268	break;
bf43fa3f AT	269	default:
	270	ws_die(pc, "malformed flow control IMP");
	271	break;
1adfc4f4 AT	272	}
	273	}
	274	break;
bf43fa3f AT	275	default:
	276	ws_die(pc, "malformed flow control IMP");
	277	break;
1adfc4f4 AT	278	}
	279	}
	280
	281	void
	282	process_imp_heap(uint8_t * code, size_t * pc, int32_t sp, int32_t hp)
	283	{
	284	switch (next_code_byte(code,pc)) {
	285	case ' ' : /* Store to heap / (hp + ((sp)-1)) = sp; sp -= 2; break;
	286	case '\t': /* Retrieve from heap / sp = (hp + *sp); break;
9686c901	287	default : ws_die(pc, "malformed heap IMP"); break;
1adfc4f4 AT	288	}
	289	}
	290
	291	void
	292	process_imp_io(uint8_t * code, size_t * pc, int32_t sp, int32_t hp)
	293	{
	294	switch (next_code_byte(code,pc)) {
	295	case ' ':
	296	/* Output */
	297	{
	298	switch (next_code_byte(code,pc)) {
	299	case ' ' : /* Output character from TOS */ printf("%c", stack_pop(sp)); break;
	300	case '\t': /* Output number from TOS */ printf("%d", stack_pop(sp)); break;
9686c901	301	default : ws_die(pc, "malformed output IMP"); break;
1adfc4f4 AT	302	}
	303	fflush(stdout);
	304	}
	305	break;
	306	case '\t':
	307	/* Input */
	308	{
	309	while (stdin_empty()) continue;
	310	char c = getchar();
	311	switch (next_code_byte(code,pc)) {
	312	case '\t': /* Input digit / c -= '0'; / fallthrough */
	313	case ' ' : /* Input character / (hp + ((*sp)--)) = c; break;
9686c901	314	default : ws_die(pc, "malformed input IMP"); break;
1adfc4f4 AT	315	}
	316	}
	317	break;
bf43fa3f	318	default: ws_die(pc, "malformed i/o IMP"); break;
1adfc4f4 AT	319	}
	320	}
	321
1adfc4f4 AT	322	int
	323	main(int argc, char ** argv)
	324	{
	325	/*
	326	* Process command line arguments
	327	*/
	328	int c;
	329	FILE * input = NULL;
	330	while ((c = getopt(argc,argv,"i:h")) != -1) {
	331	switch (c) {
	332	case 'i':
	333	if ((input = fopen(optarg, "r")) == NULL) {
	334	fprintf(stderr, "ERROR: %s: %s\n", optarg, strerror(errno));
	335	}
	336	break;
	337	case 'h':
	338	print_usage(argv);
	339	exit(EXIT_SUCCESS);
	340	break;
	341	default:
	342	break;
	343	}
	344	}
	345	if (input == NULL) {
bf43fa3f	346	fprintf(stderr, "ERROR: Must specify a VVhitespace source file with -f flag.\n");
1adfc4f4 AT	347	print_usage(argv);
	348	exit(EXIT_FAILURE);
	349	}
	350
	351	/*
bf43fa3f	352	* Read just the VVhitespace source code into memory.
1adfc4f4 AT	353	* We will use the array indices as addresses for the virtual PC when jumping to labels.
	354	*/
	355	size_t ws_code_size = 0;
	356	uint8_t temp_byte;
	357	while (fread(&temp_byte, 1, 1, input)) {
bf43fa3f AT	358	if (temp_byte == ' ' \|\| temp_byte == '\t' \|\| temp_byte == '\n' \|\| temp_byte == '\v') {
	359	ws_code_size++;
	360	}
1adfc4f4 AT	361	}
	362	rewind(input);
	363	uint8_t * ws_code_space = malloc(ws_code_size);
	364	ws_code_size = 0;
	365	while (fread(&temp_byte, 1, 1, input)) {
bf43fa3f AT	366	if (temp_byte == ' ' \|\| temp_byte == '\t' \|\| temp_byte == '\n' \|\| temp_byte == '\v') {
	367	ws_code_space[ws_code_size++] = temp_byte;
	368	}
1adfc4f4 AT	369	}
	370	fclose(input);
	371
	372	/*
	373	* Setup a stack and heap.
	374	* Assume a 32-bit word size.
	375	*/
bf43fa3f	376	// TODO: Make everything 64-bit.
1adfc4f4 AT	377	int32_t * hp = malloc(HEAPSIZE*4);
	378	int32_t * sp = malloc(STACKSIZE*4);
	379
	380	/*
	381	* Setup the return stack and the label array.
	382	*/
	383	uint32_t * rsp = malloc(RETURNSTACKSIZE*4);
bf43fa3f AT	384	uint32_t labels[65536] = {0};
bf43fa3f AT	385	populate_labels(labels, ws_code_space, ws_code_size);
1adfc4f4 AT	386
	387	/*
	388	* Main Loop
	389	*/
	390
	391	size_t pc = 0; /* Virtual program counter. Operates in the ws_code_space[] address space. */
	392	while (1) {
	393	if (pc >= ws_code_size) {
bf43fa3f AT	394	fprintf(stderr, "SIM_ERROR: PC Overrun\n Requested PC: %lu\n Max Address: %lu\n",
bf43fa3f AT	395	pc, ws_code_size-1);
1adfc4f4 AT	396	exit(EXIT_FAILURE);
1adfc4f4 AT	397	}
9686c901 AT	398	// TODO: Have the SIGTERM signal handler and normal term point return the value
9686c901 AT	399	// on TOS so I can do rudimentary automated tests.
1adfc4f4 AT	400
	401	/* Decode the IMPs */
	402	switch (ws_code_space[pc++]) {
	403	case ' ':
	404	/* Stack Manipulation */
	405	process_imp_stack(ws_code_space, &pc, &sp);
	406	break;
	407	case '\n':
	408	/* Flow Control */
	409	process_imp_flowcontrol(ws_code_space, &pc, &sp, labels, &rsp);
	410	break;
	411	case '\t':
	412	/* Arithmetic, Heap Access, or I/O */
	413	{
	414	switch (ws_code_space[pc++]) {
	415	case ' ':
	416	/* Arithmetic */
	417	process_imp_arithmetic(ws_code_space, &pc, &sp);
	418	break;
	419	case '\t':
	420	/* Heap Access */
	421	process_imp_heap(ws_code_space, &pc, &sp, &hp);
	422	break;
	423	case '\n':
	424	/* I/O */
	425	process_imp_io(ws_code_space, &pc, &sp, &hp);
	426	break;
	427	}
	428	}
	429	break;
9686c901	430	default: ws_die(&pc, "unexpected VTab"); break;
1adfc4f4 AT	431	}
	432	}
	433
	434	printf("\n");
	435	printf("Program executed.\n");
	436
	437	exit(EXIT_SUCCESS);
	438	}