gb-emu: initial commit

Add a mostly non-functional Gameboy CPU and the skeleton
of a Gameboy assembler intended for unit tests.

src/apps/gbasm.c

@@ -0,0 +1,87 @@
+/* A simple, two-pass gameboy assembler */
+
+#include <ctype.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include "gbasm/emitter.h"
+#include "gbasm/assemble.h"
+
+#define GBASM_FILE_BUFFER_SIZE (1024 * 1024)
+
+static char file_buffer[GBASM_FILE_BUFFER_SIZE];
+
+static void usage()
+{
+	printf("gbasm -i <file> -o <file>\n"
+	       " -h                 Print this usage \n"
+	       " -i   <input file>  The file to assemble\n"
+	       " -o   <output file> The file to write the assembled program to\n");
+}
+
+int main(int argc, char **argv)
+{
+	struct emitter emitter;
+	struct fd_emitter fd_emitter;
+	char opt;
+	int in_fd = -1;
+	int out_fd = -1;
+	
+	while ((opt = getopt(argc, argv, "i:o:h")) != -1) {
+
+		switch (opt) {
+		case 'o':
+			if (out_fd >= 0) {
+				close(out_fd);
+			}
+
+			out_fd = open(optarg, O_WRONLY | O_CREAT);
+			if (out_fd < 0) {
+				fprintf(stderr, "failed to open output file %s\n", optarg);
+				exit(1);
+			}
+			break;
+		case 'i':
+			if (in_fd >= 0) {
+				close(in_fd);
+			}
+
+			in_fd = open(optarg, O_RDONLY);
+			if (in_fd < 0) {
+				fprintf(stderr, "failed to open input file %s\n", optarg);
+				exit(1);
+			}
+			break;
+		case 'h':
+			usage();
+			exit(1);
+		case ':':
+			fprintf(stderr, "Option -%c requires argument\n", optopt);
+			usage();
+			exit(1);
+		case '?':
+			fprintf(stderr, "Unrecognized option -%c\n", optopt);
+			usage();
+			exit(1);
+		}
+	}
+
+	if (in_fd < 0) {
+		exit(1);
+	} else {
+		pread(in_fd, file_buffer, GBASM_FILE_BUFFER_SIZE - 1, 0);
+		file_buffer[GBASM_FILE_BUFFER_SIZE - 1] = '\0';
+	}
+
+	if (out_fd < 0) {
+		exit(1);
+	}
+
+	fd_emitter_init(&emitter, &fd_emitter, out_fd);
+
+	return gbasm_assemble(file_buffer, &emitter);	
+}