gb-emu: initial commit

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

src/gb_disas.h

@@ -0,0 +1,19 @@
+
+#ifndef _GB_DISAS_H_H
+#define _GB_DISAS_H_H
+
+const char *gb_byte_to_opcode(unsigned char byte);
+
+/* int main(int argc, char **argv) */
+/* { */
+/*     unsigned char opcode = 0; */
+/*     int bytes = 0; */
+
+/*     do { */
+/* 	bytes = read(0, &opcode, 1); */
+/* 	printf("(%d) [0x%x] %s\n", bytes, opcode, opcodes[opcode]); */
+/*     } while (bytes > 0); */
+/*     return 0; */
+/* } */
+
+#endif