Add minimal logging functionality.

src/Makefile

@@ -1,13 +1,14 @@
 CLI=rk65c02cli
 CLI_OBJS=rk65c02cli.o
 
-LIB_OBJS=rk65c02.o bus.o instruction.o emulation.o debug.o device_ram.o device_serial.o
+LIB_OBJS=rk65c02.o bus.o instruction.o emulation.o debug.o device_ram.o device_serial.o log.o
 LIB_SO=librk65c02.so
 LIB_STATIC=librk65c02.a
 
 LDFLAGS_SO=-shared
 LDFLAGS_CLI=-lreadline
 CFLAGS=-Wall -fpic -ggdb
+#CFLAGS=-Wall -fpic -ggdb -I/opt/local/include/uthash
 
 65C02ISA=65c02isa
 EMULATION=emulation

src/log.c

@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdarg.h>
+
+#include "log.h"
+
+static const char *level_str[] = {
+	"",
+	"CRITICAL",
+	"ERROR",
+	"INFO",
+	"DEBUG",
+	"TRACE"
+};
+
+static uint8_t level = LOG_INFO;
+
+void rk6502_loglevel_set(uint8_t l)
+{
+	level = l;
+}
+
+void rk6502_log(uint8_t l, const char* fmt, ...)
+{
+	va_list args;
+
+	if (l > level)
+		return;
+
+	fprintf(stderr, "%s:\t", level_str[l]);
+
+	va_start(args, fmt);
+	vfprintf(stderr, fmt, args);
+	va_end(args);
+
+	fprintf(stderr, "\n");
+}
+

src/log.h

@@ -0,0 +1,14 @@
+#include <stdint.h>
+
+#define LOG_TRACE	5
+#define LOG_DEBUG	4
+#define LOG_INFO	3
+#define LOG_ERROR	2
+#define LOG_CRIT	1
+#define LOG_NOTHING	0	/* At 0 nothing will get logged, can be set as
+				   current level, but not when creating new log
+				   messages. */
+
+void rk6502_loglevel_set(uint8_t);
+void rk6502_log(uint8_t, const char *, ...);
+

src/rk65c02.c

@@ -9,6 +9,7 @@
 #include "bus.h"
 #include "instruction.h"
 #include "rk65c02.h"
+#include "log.h"
 #include "debug.h"
 
 void rk65c02_exec(rk65c02emu_t *);
@@ -34,6 +35,8 @@ rk65c02_init(bus_t *b)
 	e.trace_head = NULL;
 	e.runtime_disassembly = false;
 
+	rk6502_log(LOG_DEBUG, "Initialized new emulator.");
+
 	return e;
 }