329 lines
8.7 KiB
C
329 lines
8.7 KiB
C
/* RETRO ------------------------------------------------------
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A personal, minimalistic forth
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Copyright (c) 2017 - 2020 Charles Childers
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Copyright (c) 2019 Luke Parrish
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This is the standard assembler for Nga. It's primarily used
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to build the RETRO kernel (retro.muri).
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---------------------------------------------------------- */
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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#include <sys/types.h>
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#ifndef BIT64
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#define CELL int32_t
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#define CELL_MIN INT_MIN + 1
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#define CELL_MAX INT_MAX - 1
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#else
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#define CELL int64_t
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#define CELL_MIN LLONG_MIN + 1
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#define CELL_MAX LLONG_MAX - 1
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#endif
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#define KiB * 1024
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#define MAX_NAMES 4096
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#define STRING_LEN 64
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#ifndef IMAGE_SIZE
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#define IMAGE_SIZE 128 KiB
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#endif
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char Labels[MAX_NAMES][STRING_LEN];
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CELL Pointers[MAX_NAMES];
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CELL np;
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char source[1 KiB];
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CELL target[IMAGE_SIZE];
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CELL here;
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typedef void (*Handler)(char *);
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void unu(char *, int, Handler);
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size_t bsd_strlcpy(char *dst, const char *src, size_t dsize);
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <string.h>
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/* *********************************************************************** */
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/* retro-unu is used to extract code blocks from a source file.
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I embed a minimal version of this here. */
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char code_start[33], code_end[33], test_start[33], test_end[33];
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void read_line(FILE *file, char *line_buffer) {
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int ch = getc(file);
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int count = 0;
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while ((ch != '\n') && (ch != EOF)) {
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line_buffer[count] = ch;
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count++;
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ch = getc(file);
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}
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line_buffer[count] = '\0';
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}
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int fence_boundary(char *buffer, int tests_enabled) {
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int flag = 1;
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if (strcmp(buffer, code_start) == 0) { flag = -1; }
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if (strcmp(buffer, code_end) == 0) { flag = -1; }
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if (tests_enabled == 0) { return flag; }
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if (strcmp(buffer, test_start) == 0) { flag = -1; }
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if (strcmp(buffer, test_end) == 0) { flag = -1; }
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return flag;
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}
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void unu(char *fname, int tests_enabled, Handler handler) {
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int inBlock = 0;
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char buffer[4096];
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FILE *fp;
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fp = fopen(fname, "r");
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if (fp == NULL) {
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printf("Unable to load file\n");
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exit(2);
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}
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while (!feof(fp)) {
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read_line(fp, buffer);
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if (fence_boundary(buffer, tests_enabled) == -1) {
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if (inBlock == 0) {
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inBlock = 1;
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} else {
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inBlock = 0;
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}
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} else {
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if (inBlock == 1) {
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handler(buffer);
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}
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}
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}
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fclose(fp);
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}
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/* *********************************************************************** */
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/* save() writes the assembled image to a file named `ngaImage`. */
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void save() {
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FILE *fp;
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if ((fp = fopen("ngaImage", "wb")) == NULL) {
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printf("Unable to save the image!\n");
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exit(2);
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}
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fwrite(&target, sizeof(CELL), here, fp);
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fclose(fp);
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}
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/* lookup() finds a label name and returs its offset in the image */
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CELL lookup(char *name) {
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CELL slice = -1;
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CELL n = np;
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while (n > 0) {
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n--;
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if (strcmp(Labels[n], name) == 0) {
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slice = Pointers[n];
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}
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}
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return slice;
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}
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/* add_label() stores a name and location for later use by lookup() */
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void add_label(char *name, CELL slice) {
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if (lookup(name) == -1) {
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bsd_strlcpy(Labels[np], name, STRING_LEN);
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Pointers[np] = slice;
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np++;
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} else {
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printf("Fatal error: %s already defined\n", name);
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exit(0);
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}
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}
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/* opcode_for() returns the opcode value for a two letter instruction name. */
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CELL opcode_for(char *s) {
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char* opcodeList = "..lidudrswpupojucaccreeqneltgtfestadsumudianorxoshzrhaieiqii";
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int16_t* s16 = (int16_t *)s;
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int16_t* op16 = (int16_t *)opcodeList;
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int i = 0;
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for (i = 0; i <= 30; i++) {
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if (s16[0] == op16[i]) {
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return i;
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}
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}
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return 0;
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}
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/* the first pass records the address for each label */
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void pass1(char *buffer) {
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switch (buffer[0]) {
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case 'i': here++; break;
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case 'r': here++; break;
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case 'd': here++; break;
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case 's': here = here + strlen(buffer) - 1; break;
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case ':': add_label(buffer+2, here); break;
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}
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}
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/* the second pass assembles the instruction bundles */
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void pass2(char *buffer) {
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unsigned int opcode;
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char inst[3];
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inst[2] = '\0';
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switch (buffer[0]) {
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case 'i': memcpy(inst, buffer + 8, 2);
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opcode = opcode_for(inst);
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opcode = opcode << 8;
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memcpy(inst, buffer + 6, 2);
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opcode += opcode_for(inst);
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opcode = opcode << 8;
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memcpy(inst, buffer + 4, 2);
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opcode += opcode_for(inst);
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opcode = opcode << 8;
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memcpy(inst, buffer + 2, 2);
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opcode += opcode_for(inst);
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target[here++] = opcode;
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break;
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case 'r': here++; break;
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case 'd': here++; break;
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case 's': here = here + strlen(buffer) - 1; break;
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case ':': break;
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}
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}
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/* the third pass assembles raw numeric values */
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void pass3(char *buffer) {
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switch (buffer[0]) {
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case 'i': here++; break;
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case 'r': here++; break;
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case 'd': target[here++] = atoi(buffer+2); break;
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case 's': here = here + strlen(buffer) - 1; break;
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case ':': break;
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}
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}
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/* the fourth pass assembles strings */
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void pass4(char *buffer) {
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unsigned int opcode;
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switch (buffer[0]) {
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case 'i': here++; break;
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case 'r': here++; break;
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case 'd': here++; break;
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case 's': opcode = 2;
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while (opcode < strlen(buffer)) {
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target[here++] = buffer[opcode++];
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}
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target[here++] = 0;
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break;
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case ':': break;
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}
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}
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/* the fifth pass resolves references to labels */
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void pass5(char *buffer) {
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switch (buffer[0]) {
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case 'i': here++; break;
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case 'r': target[here++] = lookup(buffer+2);
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if (lookup(buffer+2) == -1)
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printf("Lookup failed: '%s'\n", buffer+2);
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break;
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case 'd': here++; break;
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case 's': here = here + strlen(buffer) - 1; break;
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case ':': break;
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}
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}
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int main(int argc, char **argv) {
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bsd_strlcpy(code_start, "~~~", 32);
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bsd_strlcpy(code_end, "~~~", 32);
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bsd_strlcpy(test_start, "```", 32);
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bsd_strlcpy(test_end, "```", 32);
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np = 0;
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if (argc > 1) {
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here = 0; unu(argv[1], 0, &pass1);
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here = 0; unu(argv[1], 0, &pass2);
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here = 0; unu(argv[1], 0, &pass3);
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here = 0; unu(argv[1], 0, &pass4);
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here = 0; unu(argv[1], 0, &pass5);
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save();
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printf("Wrote %lld cells to ngaImage\n", (long long)here);
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}
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else {
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printf("No file specified.\n");
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}
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return 0;
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}
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/* *********************************************************************** */
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/* GNU libc does not include the strl* functions available on BSD systems.
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I include a copy of the OpenBSD implementation here as I'd rather use
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the safer version of the functions. */
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/*
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* Copyright (c) 1998, 2015 Todd C. Miller <Todd.Miller@courtesan.com>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Copy string src to buffer dst of size dsize. At most dsize-1
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* chars will be copied. Always NUL terminates (unless dsize == 0).
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* Returns strlen(src); if retval >= dsize, truncation occurred.
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*/
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size_t bsd_strlcpy(char *dst, const char *src, size_t dsize)
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{
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const char *osrc = src;
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size_t nleft = dsize;
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/* Copy as many bytes as will fit. */
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if (nleft != 0) {
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while (--nleft != 0) {
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if ((*dst++ = *src++) == '\0')
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break;
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}
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}
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/* Not enough room in dst, add NUL and traverse rest of src. */
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if (nleft == 0) {
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if (dsize != 0)
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*dst = '\0'; /* NUL-terminate dst */
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while (*src++)
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;
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}
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return(src - osrc - 1); /* count does not include NUL */
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}
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