librfu_stwi

Co-authored-by: Max Thomas <mtinc2@gmail.com>

include/gba/io_reg.h

@@ -137,6 +137,8 @@
 #define REG_OFFSET_DMA3CNT_H   0xde
 
 #define REG_OFFSET_TMCNT       0x100
+#define REG_OFFSET_TMCNT_L     0x100
+#define REG_OFFSET_TMCNT_H     0x102
 #define REG_OFFSET_TM0CNT      0x100
 #define REG_OFFSET_TM0CNT_L    0x100
 #define REG_OFFSET_TM0CNT_H    0x102
@@ -298,6 +300,8 @@
 #define REG_ADDR_DMA3CNT_H   (REG_BASE + REG_OFFSET_DMA3CNT_H)
 
 #define REG_ADDR_TMCNT       (REG_BASE + REG_OFFSET_TMCNT)
+#define REG_ADDR_TMCNT_L     (REG_BASE + REG_OFFSET_TMCNT_L)
+#define REG_ADDR_TMCNT_H     (REG_BASE + REG_OFFSET_TMCNT_H)
 #define REG_ADDR_TM0CNT      (REG_BASE + REG_OFFSET_TM0CNT)
 #define REG_ADDR_TM0CNT_L    (REG_BASE + REG_OFFSET_TM0CNT_L)
 #define REG_ADDR_TM0CNT_H    (REG_BASE + REG_OFFSET_TM0CNT_H)
@@ -458,6 +462,8 @@
 #define REG_DMA3CNT_H   (*(vu16 *)REG_ADDR_DMA3CNT_H)
 
 #define REG_TMCNT(n)    (*(vu16 *)(REG_ADDR_TMCNT + ((n) * 4)))
+#define REG_TMCNT_L(n)  (*(vu16 *)(REG_ADDR_TMCNT_L + ((n) * 4)))
+#define REG_TMCNT_H(n)  (*(vu16 *)(REG_ADDR_TMCNT_H + ((n) * 4)))
 #define REG_TM0CNT      (*(vu32 *)REG_ADDR_TM0CNT)
 #define REG_TM0CNT_L    (*(vu16 *)REG_ADDR_TM0CNT_L)
 #define REG_TM0CNT_H    (*(vu16 *)REG_ADDR_TM0CNT_H)

include/gba/macro.h

@@ -105,7 +105,7 @@
     }                                                     \
 }
 
-#define DmaClearLarge(dmaNum, dest, size, block, bit) \
+#define DmaClearLarge(dmaNum, dest, size, block, bit)     \
 {                                                         \
     u32 _size = size;                                     \
     while (1)                                             \
@@ -170,4 +170,14 @@
 #define DmaFill16Defvars(dmaNum, value, dest, size) DmaFillDefvars(dmaNum, value, dest, size, 16)
 #define DmaFill32Defvars(dmaNum, value, dest, size) DmaFillDefvars(dmaNum, value, dest, size, 32)
 
+#define IntrEnable(flags)                                       \
+{                                                               \
+    u16 imeTemp;                                                \
+                                                                \
+    imeTemp = REG_IME;                                          \
+    REG_IME = 0;                                                \
+    REG_IE |= flags;                                            \
+    REG_IME = imeTemp;                                          \
+}
+
 #endif // GUARD_GBA_MACRO_H

include/librfu.h

@@ -108,7 +108,7 @@ struct RfuStruct
     u8 ackActiveCommand;
     u8 timerSelect;
     u8 unk_b;
-    s32 timerState;
+    u32 timerState; // this field is s32 in emerald
     vu8 timerActive;
     u8 unk_11;
     vu16 error;
@@ -126,10 +126,10 @@ struct RfuStruct
 
 struct RfuIntrStruct
 {
-    u8 rxPacketAlloc[0x74];
-    u8 txPacketAlloc[0x74];
-    u8 block1[0x960];
-    u8 block2[0x30];
+    union RfuPacket rxPacketAlloc;
+    union RfuPacket txPacketAlloc;
+    u8 block1[0x960]; // size of librfu_intr.s binary
+    struct RfuStruct block2;
 };
 
 struct RfuSlotStatusUNI
@@ -248,14 +248,6 @@ struct Unk_3007470
     u16 unkA;
 };
 
-struct STWIStruct
-{
-    // TODO: resolve the struct
-    u8 unk_0[232];
-    u8 function[2400];
-    struct RfuStruct STWIStatus;
-};
-
 struct Unk_3001190
 {
     struct RfuLinkStatus linkStatus;
@@ -263,7 +255,7 @@ struct Unk_3001190
     struct RfuFixed fixed;
     struct RfuSlotStatusNI NI[4];
     struct RfuSlotStatusUNI UNI[4];
-    struct STWIStruct STWI;
+    struct RfuIntrStruct intr;
 };
 
 extern struct RfuStruct *gRfuState;
@@ -275,7 +267,6 @@ extern struct RfuSlotStatusUNI *gRfuSlotStatusUNI[4];
 extern struct Unk_3007470 gUnknown_3007470;
 
 void rfu_STC_clearAPIVariables(void);
-void STWI_init_all(struct RfuIntrStruct * interruptStruct, IntrFunc *interrupt, bool8 copyInterruptToRam);
 void rfu_REQ_stopMode(void);
 void rfu_waitREQComplete(void);
 u32 rfu_REQBN_softReset_and_checkID(void);
@@ -323,4 +314,50 @@ void rfu_UNI_clearRecvNewDataFlag(u8 a0);
 void rfu_REQ_PARENT_resumeRetransmitAndChange(void);
 void rfu_NI_setSendData(u8, u8, const void *, u32);
 
+// librfu_intr
+void IntrSIO32(void);
+
+// librfu_stwi
+void STWI_init_all(struct RfuIntrStruct * interruptStruct, IntrFunc *interrupt, bool8 copyInterruptToRam);
+void STWI_set_MS_mode(u8 mode);
+void STWI_init_Callback_M(void);
+void STWI_init_Callback_S(void);
+void STWI_set_Callback_M(void (*callbackM)());
+void STWI_set_Callback_S(void (*callbackS)());
+void STWI_init_timer(IntrFunc *interrupt, s32 timerSelect);
+void AgbRFU_SoftReset(void);
+void STWI_set_Callback_ID(u32 id);
+u16 STWI_read_status(u8 index);
+u16 STWI_poll_CommandEnd(void);
+void STWI_send_DataRxREQ(void);
+void STWI_send_MS_ChangeREQ(void);
+void STWI_send_StopModeREQ(void);
+void STWI_send_SystemStatusREQ(void);
+void STWI_send_GameConfigREQ(u8 *unk1, u8 *data);
+void STWI_send_ResetREQ(void);
+void STWI_send_LinkStatusREQ(void);
+void STWI_send_VersionStatusREQ(void);
+void STWI_send_SlotStatusREQ(void);
+void STWI_send_ConfigStatusREQ(void);
+void STWI_send_ResumeRetransmitAndChangeREQ(void);
+void STWI_send_SystemConfigREQ(u16 unk1, u8 unk2, u8 unk3);
+void STWI_send_SC_StartREQ(void);
+void STWI_send_SC_PollingREQ(void);
+void STWI_send_SC_EndREQ(void);
+void STWI_send_SP_StartREQ(void);
+void STWI_send_SP_PollingREQ(void);
+void STWI_send_SP_EndREQ(void);
+void STWI_send_CP_StartREQ(u16 unk1);
+void STWI_send_CP_PollingREQ(void);
+void STWI_send_CP_EndREQ(void);
+void STWI_send_DataTxREQ(const void *in, u8 size);
+void STWI_send_DataTxAndChangeREQ(const void *in, u8 size);
+void STWI_send_DataReadyAndChangeREQ(u8 unk);
+void STWI_send_DisconnectedAndChangeREQ(u8 unk0, u8 unk1);
+void STWI_send_DisconnectREQ(u8 unk);
+void STWI_send_TestModeREQ(u8 unk0, u8 unk1);
+void STWI_send_CPR_StartREQ(u16 unk0, u16 unk1, u8 unk2);
+void STWI_send_CPR_PollingREQ(void);
+void STWI_send_CPR_EndREQ(void);
+
 #endif // GUARD_LIBRFU_H

ld_script.txt

@@ -317,7 +317,7 @@ SECTIONS {
         src/agb_flash_1m.o(.text);
         src/agb_flash_mx.o(.text);
         src/agb_flash_le.o(.text);
-        asm/librfu_stwi.o(.text);
+        src/librfu_stwi.o(.text);
         asm/librfu_intr.o(.text);
         asm/librfu.o(.text);
         src/isagbprn.o(.text);

src/librfu_stwi.c

@@ -0,0 +1,645 @@
+#include "global.h"
+#include "librfu.h"
+
+static void STWI_intr_timer(void);
+static u16 STWI_init(u8 request);
+static s32 STWI_start_Command(void);
+static void STWI_set_timer(u8 unk);
+static void STWI_stop_timer(void);
+static s32 STWI_restart_Command(void);
+static s32 STWI_reset_ClockCounter(void);
+
+void STWI_init_all(struct RfuIntrStruct *interruptStruct, IntrFunc *interrupt, bool8 copyInterruptToRam)
+{
+    // If we're copying our interrupt into RAM, DMA it to block1 and use
+    // block2 for our RfuStruct, otherwise block1 holds the RfuStruct.
+    // interrupt usually is a pointer to gIntrTable[1]
+    if (copyInterruptToRam == TRUE)
+    {
+        *interrupt = (IntrFunc)interruptStruct->block1;
+        DmaCopy16(3, &IntrSIO32, interruptStruct->block1, sizeof(interruptStruct->block1));
+        gRfuState = &interruptStruct->block2;
+    }
+    else
+    {
+        *interrupt = IntrSIO32;
+        gRfuState = (struct RfuStruct *)interruptStruct->block1;
+    }
+    gRfuState->rxPacket = &interruptStruct->rxPacketAlloc;
+    gRfuState->txPacket = &interruptStruct->txPacketAlloc;
+    gRfuState->msMode = 1;
+    gRfuState->state = 0;
+    gRfuState->reqLength = 0;
+    gRfuState->reqNext = 0;
+    gRfuState->ackLength = 0;
+    gRfuState->ackNext = 0;
+    gRfuState->ackActiveCommand = 0;
+    gRfuState->timerState = 0;
+    gRfuState->timerActive = 0;
+    gRfuState->error = 0;
+    gRfuState->recoveryCount = 0;
+    gRfuState->unk_2c = 0;
+    REG_RCNT = 0x100; // TODO: mystery bit? 
+    REG_SIOCNT = SIO_INTR_ENABLE | SIO_32BIT_MODE | SIO_115200_BPS;
+    STWI_init_Callback_M();
+    STWI_init_Callback_S();
+    IntrEnable(INTR_FLAG_SERIAL);
+}
+
+void STWI_init_timer(IntrFunc *interrupt, s32 timerSelect)
+{
+    *interrupt = STWI_intr_timer;
+    gRfuState->timerSelect = timerSelect;
+    IntrEnable(INTR_FLAG_TIMER0 << gRfuState->timerSelect);
+}
+
+void AgbRFU_SoftReset(void)
+{
+    vu16 *timerL;
+    vu16 *timerH;
+
+    REG_RCNT = 0x8000;
+    REG_RCNT = 0x80A0; // all these bits are undocumented
+    timerL = &REG_TMCNT_L(gRfuState->timerSelect);
+    timerH = &REG_TMCNT_H(gRfuState->timerSelect);
+    *timerH = 0;
+    *timerL = 0;
+    *timerH = 0x83;
+    while (*timerL <= 0x11)
+        REG_RCNT = 0x80A2;
+    *timerH = 3;
+    REG_RCNT = 0x80A0;
+    REG_SIOCNT = SIO_INTR_ENABLE | SIO_32BIT_MODE | SIO_115200_BPS;
+    gRfuState->state = 0;
+    gRfuState->reqLength = 0;
+    gRfuState->reqNext = 0;
+    gRfuState->reqActiveCommand = 0;
+    gRfuState->ackLength = 0;
+    gRfuState->ackNext = 0;
+    gRfuState->ackActiveCommand = 0;
+    gRfuState->timerState = 0;
+    gRfuState->timerActive = 0;
+    gRfuState->error = 0;
+    gRfuState->msMode = 1;
+    gRfuState->recoveryCount = 0;
+    gRfuState->unk_2c = 0;
+}
+
+void STWI_set_MS_mode(u8 mode)
+{
+    gRfuState->msMode = mode;
+}
+
+u16 STWI_read_status(u8 index)
+{
+    switch (index)
+    {
+    case 0:
+        return gRfuState->error;
+    case 1:
+        return gRfuState->msMode;
+    case 2:
+        return gRfuState->state;
+    case 3:
+        return gRfuState->reqActiveCommand;
+    default:
+        return 0xFFFF;
+    }
+}
+
+void STWI_init_Callback_M(void)
+{
+    STWI_set_Callback_M(NULL);
+}
+
+void STWI_init_Callback_S(void)
+{
+    STWI_set_Callback_S(NULL);
+}
+
+void STWI_set_Callback_M(void (*callbackM)())
+{
+    gRfuState->callbackM = callbackM;
+}
+
+void STWI_set_Callback_S(void (*callbackS)())
+{
+    gRfuState->callbackS = callbackS;
+}
+
+void STWI_set_Callback_ID(u32 id)
+{
+    gRfuState->callbackId = id;
+}
+
+u16 STWI_poll_CommandEnd(void)
+{
+    while (gRfuState->unk_2c == TRUE)
+        ;
+    return gRfuState->error;
+}
+
+void STWI_send_ResetREQ(void)
+{
+    if (!STWI_init(RFU_RESET))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_LinkStatusREQ(void)
+{
+    if (!STWI_init(RFU_LINK_STATUS))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_VersionStatusREQ(void)
+{
+    if (!STWI_init(RFU_VERSION_STATUS))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SystemStatusREQ(void)
+{
+    if (!STWI_init(RFU_SYSTEM_STATUS))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SlotStatusREQ(void)
+{
+    if (!STWI_init(RFU_SLOT_STATUS))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_ConfigStatusREQ(void)
+{
+    if (!STWI_init(RFU_CONFIG_STATUS))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_GameConfigREQ(u8 *unk1, u8 *data)
+{
+    u8 *packetBytes;
+    s32 i;
+
+    if (!STWI_init(RFU_GAME_CONFIG))
+    {
+        gRfuState->reqLength = 6;
+        // TODO: what is unk1
+        packetBytes = gRfuState->txPacket->rfuPacket8.data;
+        packetBytes += sizeof(u32);
+        *(u16 *)packetBytes = *(u16 *)unk1;
+        packetBytes += sizeof(u16);
+        unk1 += sizeof(u16);
+        for (i = 0; i < 14; ++i)
+        {
+            *packetBytes = *unk1;
+            ++packetBytes;
+            ++unk1;
+        }
+        for (i = 0; i < 8; ++i)
+        {
+            *packetBytes = *data;
+            ++packetBytes;
+            ++data;
+        }
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SystemConfigREQ(u16 unk1, u8 unk2, u8 unk3)
+{
+    if (!STWI_init(RFU_SYSTEM_CONFIG))
+    {
+        u8 *packetBytes;
+
+        gRfuState->reqLength = 1;
+        packetBytes = gRfuState->txPacket->rfuPacket8.data;
+        packetBytes += sizeof(u32);
+        *packetBytes++ = unk3;
+        *packetBytes++ = unk2;
+        *(u16*)packetBytes = unk1;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SC_StartREQ(void)
+{
+    if (!STWI_init(RFU_SC_START))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SC_PollingREQ(void)
+{
+    if (!STWI_init(RFU_SC_POLLING))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SC_EndREQ(void)
+{
+    if (!STWI_init(RFU_SC_END))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SP_StartREQ(void)
+{
+    if (!STWI_init(RFU_SP_START))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SP_PollingREQ(void)
+{
+    if (!STWI_init(RFU_SP_POLLING))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_SP_EndREQ(void)
+{
+    if (!STWI_init(RFU_SP_END))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_CP_StartREQ(u16 unk1)
+{
+    if (!STWI_init(RFU_CP_START))
+    {
+        gRfuState->reqLength = 1;
+        gRfuState->txPacket->rfuPacket32.data[0] = unk1;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_CP_PollingREQ(void)
+{
+    if (!STWI_init(RFU_CP_POLLING))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_CP_EndREQ(void)
+{
+    if (!STWI_init(RFU_CP_END))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_DataTxREQ(const void *in, u8 size)
+{
+    if (!STWI_init(RFU_DATA_TX))
+    {
+        u8 reqLength = (size / sizeof(u32));
+        if (size & (sizeof(u32) - 1))
+            reqLength += 1;
+        gRfuState->reqLength = reqLength;
+        CpuCopy32(in, gRfuState->txPacket->rfuPacket32.data, gRfuState->reqLength * sizeof(u32));
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_DataTxAndChangeREQ(const void *in, u8 size)
+{
+    if (!STWI_init(RFU_DATA_TX_AND_CHANGE))
+    {
+        u8 reqLength = (size / sizeof(u32));
+        if (size & (sizeof(u32) - 1))
+            reqLength += 1;
+        gRfuState->reqLength = reqLength;
+        CpuCopy32(in, gRfuState->txPacket->rfuPacket32.data, gRfuState->reqLength * sizeof(u32));
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_DataRxREQ(void)
+{
+    if (!STWI_init(RFU_DATA_RX))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_MS_ChangeREQ(void)
+{
+    if (!STWI_init(RFU_MS_CHANGE))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_DataReadyAndChangeREQ(u8 unk)
+{
+    if (!STWI_init(RFU_DATA_READY_AND_CHANGE))
+    {
+        if (!unk)
+        {
+            gRfuState->reqLength = 0;
+        }
+        else
+        {
+            u8 *packetBytes;
+
+            gRfuState->reqLength = 1;
+            packetBytes = gRfuState->txPacket->rfuPacket8.data;
+            packetBytes += sizeof(u32);
+            *packetBytes++ = unk;
+            *packetBytes++ = 0;
+            *packetBytes++ = 0;
+            *packetBytes = 0;
+        }
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_DisconnectedAndChangeREQ(u8 unk0, u8 unk1)
+{
+    if (!STWI_init(RFU_DISCONNECTED_AND_CHANGE))
+    {
+        u8 *packetBytes;
+
+        gRfuState->reqLength = 1;
+        packetBytes = gRfuState->txPacket->rfuPacket8.data;
+        packetBytes += sizeof(u32);
+        *packetBytes++ = unk0;
+        *packetBytes++ = unk1;
+        *packetBytes++ = 0;
+        *packetBytes = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_ResumeRetransmitAndChangeREQ(void)
+{
+    if (!STWI_init(RFU_RESUME_RETRANSMIT_AND_CHANGE))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_DisconnectREQ(u8 unk)
+{
+    if (!STWI_init(RFU_DISCONNECT))
+    {
+        gRfuState->reqLength = 1;
+        gRfuState->txPacket->rfuPacket32.data[0] = unk;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_TestModeREQ(u8 unk0, u8 unk1)
+{
+    if (!STWI_init(RFU_TEST_MODE))
+    {
+        gRfuState->reqLength = 1;
+        gRfuState->txPacket->rfuPacket32.data[0] = unk0 | (unk1 << 8);
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_CPR_StartREQ(u16 unk0, u16 unk1, u8 unk2)
+{
+    u32 *packetData;
+    u32 arg1;
+
+    if (!STWI_init(RFU_CPR_START))
+    {
+        gRfuState->reqLength = 2;
+        arg1 = unk1 | (unk0 << 16);
+        packetData = gRfuState->txPacket->rfuPacket32.data;
+        packetData[0] = arg1;
+        packetData[1] = unk2;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_CPR_PollingREQ(void)
+{
+    if (!STWI_init(RFU_CPR_POLLING))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_CPR_EndREQ(void)
+{
+    if (!STWI_init(RFU_CPR_END))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+void STWI_send_StopModeREQ(void)
+{
+    if (!STWI_init(RFU_STOP_MODE))
+    {
+        gRfuState->reqLength = 0;
+        STWI_start_Command();
+    }
+}
+
+static void STWI_intr_timer(void)
+{
+    switch (gRfuState->timerState)
+    {
+    // TODO: Make an enum for these
+    case 2:
+        gRfuState->timerActive = 1;
+        STWI_set_timer(50);
+        break;
+    case 1:
+    case 4:
+        STWI_stop_timer();
+        STWI_restart_Command();
+        break;
+    case 3:
+        gRfuState->timerActive = 1;
+        STWI_stop_timer();
+        STWI_reset_ClockCounter();
+        if (gRfuState->callbackM)
+            gRfuState->callbackM(255, 0);
+        break;
+    }
+}
+
+static void STWI_set_timer(u8 unk)
+{
+    vu16 *timerL;
+    vu16 *timerH;
+
+    timerL = &REG_TMCNT_L(gRfuState->timerSelect);
+    timerH = &REG_TMCNT_H(gRfuState->timerSelect);
+    REG_IME = 0;
+    switch (unk)
+    {
+    case 50:
+        *timerL = 0xFCCB;
+        gRfuState->timerState = 1;
+        break;
+    case 80:
+        *timerL = 0xFAE0;
+        gRfuState->timerState = 2;
+        break;
+    case 100:
+        *timerL = 0xF996;
+        gRfuState->timerState = 3;
+        break;
+    case 130:
+        *timerL = 0xF7AD;
+        gRfuState->timerState = 4;
+        break;
+    }
+    *timerH = TIMER_ENABLE | TIMER_INTR_ENABLE | TIMER_1024CLK;
+    REG_IF = INTR_FLAG_TIMER0 << gRfuState->timerSelect;
+    REG_IME = 1;
+}
+
+static void STWI_stop_timer(void)
+{
+    gRfuState->timerState = 0;
+    REG_TMCNT_L(gRfuState->timerSelect) = 0;
+    REG_TMCNT_H(gRfuState->timerSelect) = 0;
+}
+
+static u16 STWI_init(u8 request)
+{
+    if (!REG_IME)
+    {
+        gRfuState->error = 6;
+        if (gRfuState->callbackM)
+            gRfuState->callbackM(request, gRfuState->error);
+        return TRUE;
+    }
+    else if (gRfuState->unk_2c == TRUE)
+    {
+        gRfuState->error = 2;
+        gRfuState->unk_2c = FALSE;
+        if (gRfuState->callbackM)
+            gRfuState->callbackM(request, gRfuState->error);
+        return TRUE;
+    }
+    else if(!gRfuState->msMode)
+    {
+        gRfuState->error = 4;
+        if (gRfuState->callbackM)
+            gRfuState->callbackM(request, gRfuState->error, gRfuState);
+        return TRUE;
+    }
+    else
+    {
+        gRfuState->unk_2c = TRUE;
+        gRfuState->reqActiveCommand = request;
+        gRfuState->state = 0;
+        gRfuState->reqLength = 0;
+        gRfuState->reqNext = 0;
+        gRfuState->ackLength = 0;
+        gRfuState->ackNext = 0;
+        gRfuState->ackActiveCommand = 0;
+        gRfuState->timerState = 0;
+        gRfuState->timerActive = 0;
+        gRfuState->error = 0;
+        gRfuState->recoveryCount = 0;
+        REG_RCNT = 0x100;
+        REG_SIOCNT = SIO_INTR_ENABLE | SIO_32BIT_MODE | SIO_115200_BPS;
+        return FALSE;
+    }
+}
+
+static s32 STWI_start_Command(void)
+{
+    u16 imeTemp;
+
+    // equivalent to gRfuState->txPacket->rfuPacket32.command, 
+    // but the cast here is required to avoid register issue
+    *(u32 *)gRfuState->txPacket->rfuPacket8.data = 0x99660000 | (gRfuState->reqLength << 8) | gRfuState->reqActiveCommand;
+    REG_SIODATA32 = gRfuState->txPacket->rfuPacket32.command;
+    gRfuState->state = 0;
+    gRfuState->reqNext = 1;
+    imeTemp = REG_IME;
+    REG_IME = 0;
+    REG_IE |= (INTR_FLAG_TIMER0 << gRfuState->timerSelect);
+    REG_IE |= INTR_FLAG_SERIAL;
+    REG_IME = imeTemp;
+    REG_SIOCNT = SIO_INTR_ENABLE | SIO_32BIT_MODE | SIO_MULTI_BUSY | SIO_115200_BPS;
+    return 0;
+}
+
+static s32 STWI_restart_Command(void)
+{
+    if (gRfuState->recoveryCount <= 1)
+    {
+        ++gRfuState->recoveryCount;
+        STWI_start_Command();
+    }
+    else
+    {
+        if (gRfuState->reqActiveCommand == RFU_MS_CHANGE || gRfuState->reqActiveCommand == RFU_DATA_TX_AND_CHANGE || gRfuState->reqActiveCommand == RFU_UNK35 || gRfuState->reqActiveCommand == RFU_RESUME_RETRANSMIT_AND_CHANGE)
+        {
+            gRfuState->error = 1;
+            gRfuState->unk_2c = 0;
+            if (gRfuState->callbackM)
+                gRfuState->callbackM(gRfuState->reqActiveCommand, gRfuState->error);
+        }
+        else
+        {
+            gRfuState->error = 1;
+            gRfuState->unk_2c = 0;
+            if (gRfuState->callbackM)
+                gRfuState->callbackM(gRfuState->reqActiveCommand, gRfuState->error);
+            gRfuState->state = 4; // TODO: what's 4
+        }
+    }
+    return 0;
+}
+
+static s32 STWI_reset_ClockCounter(void)
+{
+    gRfuState->state = 5; // TODO: what is 5
+    gRfuState->reqLength = 0;
+    gRfuState->reqNext = 0;
+    REG_SIODATA32 = (1 << 31);
+    REG_SIOCNT = 0;
+    REG_SIOCNT = SIO_INTR_ENABLE | SIO_32BIT_MODE | SIO_115200_BPS;
+    REG_SIOCNT = (SIO_INTR_ENABLE | SIO_32BIT_MODE | SIO_115200_BPS) + 0x7F;
+    return 0;
+}