Add c8dump

1 files changed, 252 insertions, 0 deletions

diff --git a/src/c8dump/main.c b/src/c8dump/main.c
new file mode 100644
index 0000000..c9e429b
--- /dev/null
+++ b/src/c8dump/main.c
@@ -0,0 +1,252 @@
+#include <sys/stat.h>
+
+#include <fcntl.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <builder.h>
+
+#include "cerr.h"
+#include "macros.h"
+
+#define MEM_RESERVED 0x200
+#define MEM_TOTAL    0xFFF
+#define LABEL_BUFSIZ (sizeof("label_4095"))
+
+static void dumpfile(int, const char *);
+static const char *getlabel(uint16_t);
+
+static uint16_t labelsfxs[MEM_TOTAL - MEM_RESERVED + 1];
+
+int
+main(int argc, char **argv)
+{
+	int opt;
+	const struct option longopts[] = {
+		{"help",  no_argument, nullptr, 'h'},
+		{nullptr, no_argument, nullptr, 0  },
+	};
+
+	cerrinit(*argv);
+	while ((opt = getopt_long(argc, argv, "h", longopts, nullptr)) != -1) {
+		switch (opt) {
+		case 'h':
+			execlp("man", "man", "1", argv[0], nullptr);
+			die("execlp: man 1 %s", argv[0]);
+		default:
+			fprintf(stderr,
+			        "Usage: %s [file ...]\n"
+			        "       %s -h\n",
+			        argv[0], argv[0]);
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	argc -= optind;
+	argv += optind;
+
+	if (!argc)
+		dumpfile(STDIN_FILENO, "-");
+	for (int i = 0; i < argc; i++) {
+		if (streq("-", argv[i]))
+			dumpfile(STDIN_FILENO, "-");
+		else {
+			int fd;
+			if ((fd = open(argv[i], O_RDONLY)) == -1)
+				die("open: %s", argv[i]);
+			dumpfile(fd, argv[i]);
+			close(fd);
+		}
+	}
+
+	return EXIT_SUCCESS;
+}
+
+void
+dumpfile(int fd, const char *filename)
+{
+	char *buf;
+	size_t blksize;
+	ssize_t nr;
+	struct stat st;
+	struct u8str sb;
+
+	if (fstat(fd, &st) == -1)
+		die("fstat: %s", filename);
+	blksize = MAX(st.st_blksize, BUFSIZ);
+	if (!(buf = malloc(blksize)))
+		die("malloc");
+
+	/* Load the contents of the file into sb */
+	u8strinit(&sb, S_ISREG(st.st_mode) ? (size_t)st.st_size : blksize);
+	while ((nr = read(fd, buf, blksize)) > 0) {
+		struct u8view v = {
+			.p = buf,
+			.len = nr,
+		};
+		if (!u8strpush(&sb, v))
+			die("u8strpush");
+	}
+	if (nr == -1)
+		die("read: %s", filename);
+
+	free(buf);
+
+	if (sb.len & 1) {
+		diex("%s: binary size (%zu B) is odd; missing padding bytes?", filename,
+		     sb.len);
+	}
+
+	for (size_t i = 0, j = 0; i < sb.len; i += 2) {
+		uint16_t op = (sb.p[i] << 8) | sb.p[i + 1];
+		switch (op >> 12) {
+		case 0x0:
+		case 0x1:
+		case 0x2:
+		case 0xA:
+		case 0xB:;
+			uint16_t addr = op & 0xFFF;
+			if (op != 0x00E0 && op != 0x00EE && addr >= MEM_RESERVED
+			    && !labelsfxs[addr - MEM_RESERVED])
+			{
+				labelsfxs[addr - MEM_RESERVED] = ++j;
+			}
+		}
+	}
+
+	for (size_t i = 0; i < sb.len; i += 2) {
+		uint16_t op = (sb.p[i] << 8) | sb.p[i + 1];
+		static bool indent;
+
+		if (i < lengthof(labelsfxs) && labelsfxs[i]) {
+			printf("%s:\n", getlabel(i + MEM_RESERVED));
+			indent = true;
+		}
+		if (indent)
+			putchar('\t');
+
+		switch (op >> 12) {
+		case 0x0:
+		case 0x1:
+		case 0x2:
+		case 0xA:
+		case 0xB:;
+			static const char *ops_1[] = {
+				[0x0] = "sys",  [0x1] = "jp",    [0x2] = "call",
+				[0xA] = "ld i", [0xB] = "jp v0",
+			};
+			if (op == 0x00E0)
+				puts("cls");
+			else if (op == 0x00EE)
+				puts("ret");
+			else
+				printf("%s %s\n", ops_1[op >> 12], getlabel(op & 0xFFF));
+			break;
+
+		case 0x3:
+		case 0x4:
+		case 0x6:
+		case 0x7:
+		case 0xC:;
+			static const char *ops_2[] = {
+				[0x3] = "se",  [0x4] = "sne", [0x6] = "ld",
+				[0x7] = "add", [0xC] = "rnd",
+			};
+			printf("%s v%x 0x%02X\n", ops_2[op >> 12], (op >> 8) & 0xF,
+			       op & 0xFF);
+			break;
+
+		case 0x5:
+		case 0x8:
+		case 0x9:
+		case 0xD:;
+			uint8_t n1, n2, n3, n4, i;
+			static const char *ops_3[0xFF + 1] = {
+				[0x50] = "se",   [0x80] = "ld",  [0x81] = "or",  [0x82] = "and",
+				[0x83] = "xor",  [0x84] = "add", [0x85] = "sub", [0x86] = "shr",
+				[0x87] = "subn", [0x8E] = "shl", [0x90] = "sne",
+			};
+
+			n1 = op >> 12;
+			n2 = (op >> 8) & 0xF;
+			n3 = (op >> 4) & 0xF;
+			n4 = (op >> 0) & 0xF;
+			i = (n1 << 4) | n4;
+
+			if (n1 == 0xD)
+				printf("drw v%x v%x %u\n", n2, n3, n4);
+			else if (!ops_3[i])
+				goto print_bytes;
+			else {
+				printf(n4 == 0x6 || n4 == 0xE ? "%s v%x\n" : "%s v%x v%x\n",
+				       ops_3[i], n2, n3);
+			}
+			break;
+
+		case 0xE:
+			if (op & 0xFF != 0x9E)
+				goto print_bytes;
+			printf("skp v%x\n", (op >> 12) & 0xF);
+			break;
+
+		case 0xF:;
+			uint8_t x = (op >> 8) & 0xF;
+			switch (op & 0xFF) {
+			case 0x07:
+				printf("ld v%x dt\n", x);
+				break;
+			case 0x0A:
+				printf("ld v%x k\n", x);
+				break;
+			case 0x15:
+				printf("ld dt v%x\n", x);
+				break;
+			case 0x18:
+				printf("ld st v%x\n", x);
+				break;
+			case 0x1E:
+				printf("add i v%x\n", x);
+				break;
+			case 0x29:
+				printf("hex v%x\n", x);
+				break;
+			case 0x33:
+				printf("bcd v%x\n", x);
+				break;
+			case 0x55:
+				printf("stor v%x\n", x);
+				break;
+			case 0x65:
+				printf("rstr v%x\n", x);
+				break;
+			default:
+				goto print_bytes;
+			}
+			break;
+
+		default:
+print_bytes:
+			printf("db 0x%02X\n%sdb 0x%02X\n", op >> 8, indent ? "\t" : "",
+			       op & 0xFF);
+		}
+	}
+
+	u8strfree(sb);
+}
+
+const char *
+getlabel(uint16_t addr)
+{
+	static char buf[LABEL_BUFSIZ + 69];
+	if (addr < MEM_RESERVED)
+		snprintf(buf, sizeof(buf), "0x%03X", addr);
+	else {
+		snprintf(buf, sizeof(buf), "label_%" PRIu16,
+		         labelsfxs[addr - MEM_RESERVED]);
+	}
+	return buf;
+}