mgba_logger.c

#include "mgba_logger.h"
 
#include "util.h"
 
#ifdef MGBA_LOGGING
 
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <tonc.h>
 
#define MGBA_REG_DEBUG_ENABLE ((vu16*)0x4FFF780)
#define MGBA_REG_DEBUG_FLAGS  ((vu16*)0x4FFF700)
#define MGBA_REG_DEBUG_STRING ((char*)0x4FFF600)
 
static const u32 MGBA_ENABLE_MAGIC = 0xC0DE;
static const u32 MGBA_ENABLE_OK = 0x1DEA;
static const u32 MGBA_LOG_SEND = 0x100;
static const u32 MGBA_LOG_BUFFER_SIZE = 0x100;
static const u16 MGBA_LOG_LEVEL_MASK = 0x7;
 
static bool s_mgba_logger_available = false;
 
bool mgba_logger_init(void)
{
    *MGBA_REG_DEBUG_ENABLE = MGBA_ENABLE_MAGIC;
    s_mgba_logger_available = (*MGBA_REG_DEBUG_ENABLE == MGBA_ENABLE_OK);
    return s_mgba_logger_available;
}
 
static void mgba_vprintf(MgbaLogLevel level, const char* fmt, va_list args)
{
    if (!s_mgba_logger_available)
    {
        // If the logger is not available, we can't log any error at all
        return;
    }
 
    /* This ends up being sort of a recursive call, but it has to stop after one level
     * because the macro is certain to not pass a NULL message.
     */
    GBAL_RETURN_IF_NULL(fmt, RET_NONE);
 
    vsnprintf(MGBA_REG_DEBUG_STRING, MGBA_LOG_BUFFER_SIZE, fmt, args);
 
    *MGBA_REG_DEBUG_FLAGS = ((uint16_t)level & MGBA_LOG_LEVEL_MASK) | MGBA_LOG_SEND;
}
 
void mgba_printf(MgbaLogLevel level, const char* fmt, ...)
{
    va_list args;
    va_start(args, fmt);
    mgba_vprintf(level, fmt, args);
    va_end(args);
}
 
void mgba_func_printf(MgbaLogLevel level, const char* func_name, const char* fmt, ...)
{
    if (!s_mgba_logger_available)
    {
        // If the logger is not available, we can't log any error at all
        return;
    }
 
    /* This ends up being a recursive call, but it has to stop after one level
     * because this does not pass a NULL message.
     * Not checking func_name, relying both on the macro to pass __func__ and
     * on the printf function to handle it gracefully even in the off case.
     */
    GBAL_CUST_MSG_RETURN_IF_NULL(
        fmt,
        RET_NONE,
        "%s() passed NULL message at log level %d",
        func_name,
        level
    );
 
    char printed_str_buff[MGBA_LOG_BUFFER_SIZE];
 
    // Expand the format first so the full string is truncated in case it's too long
    va_list args;
    va_start(args, fmt);
    vsnprintf(printed_str_buff, sizeof(printed_str_buff), fmt, args);
    va_end(args);
    mgba_printf(level, "%s(): %s", func_name, printed_str_buff);
}
 
#else
 
// Noop stubs
bool mgba_logger_init(void)
{
    return false;
}
 
void mgba_printf(MgbaLogLevel level, const char* fmt, ...)
{
}
 
void mgba_func_printf(MgbaLogLevel level, const char* func_name, const char* fmt, ...)
{
}
#endif