psxbios: Some games read from address 0, fix that.

[pcsx_rearmed.git] / libpcsxcore / psxbios.c

diff --git a/libpcsxcore/psxbios.c b/libpcsxcore/psxbios.c
index 8b9c99a..7b2c05f 100644 (file)
--- a/libpcsxcore/psxbios.c
+++ b/libpcsxcore/psxbios.c
@@ -307,6 +307,8 @@ static inline void DeliverEvent(u32 ev, u32 spec) {
        } else Event[ev][spec].status = EvStALREADY;
 }
 
+static unsigned interrupt_r26=0x8004E8B0;
+
 static inline void SaveRegs() {
        memcpy(regs, psxRegs.GPR.r, 32*4);
        regs[32] = psxRegs.GPR.n.lo;
@@ -1555,6 +1557,13 @@ void psxBios_SetMem() { // 9f
        pc0 = ra;
 }
 
+/* TODO FIXME : Not compliant. -1 indicates failure but using 1 for now. */
+void psxBios_get_cd_status(void) //a6
+{
+       v0 = 1;
+       pc0 = ra;
+}
+
 void psxBios__card_info() { // ab
 #ifdef PSXBIOS_LOG
        PSXBIOS_LOG("psxBios_%s: %x\n", biosA0n[0xab], a0);
@@ -1968,6 +1977,7 @@ void psxBios_ReturnFromException() { // 17
        LoadRegs();
 
        pc0 = psxRegs.CP0.n.EPC;
+       k0 = interrupt_r26;
        if (psxRegs.CP0.n.Cause & 0x80000000) pc0 += 4;
 
        psxRegs.CP0.n.Status = (psxRegs.CP0.n.Status & 0xfffffff0) |
@@ -2275,7 +2285,7 @@ void psxBios_firstfile() { // 42
        if (pa0) {
                strcpy(ffile, pa0);
                pfile = ffile+5;
-               nfile = 1;
+               nfile = 0;
                if (!strncmp(pa0, "bu00", 4)) {
                        // firstfile() calls _card_read() internally, so deliver it's event
                        DeliverEvent(0x11, 0x2);
@@ -2595,6 +2605,15 @@ void psxBios__card_status() { // 5c
        PSXBIOS_LOG("psxBios_%s: %x\n", biosB0n[0x5c], a0);
 #endif
 
+       v0 = card_active_chan;
+       pc0 = ra;
+}
+
+void psxBios__card_wait() { // 5d
+#ifdef PSXBIOS_LOG
+       PSXBIOS_LOG("psxBios_%s: %x\n", biosB0n[0x5d], a0);
+#endif
+
        v0 = 1;
        pc0 = ra;
 }
@@ -2846,7 +2865,7 @@ void psxBiosInit() {
        //biosA0[0xa3] = psxBios_DequeueCdIntr;
        //biosA0[0xa4] = psxBios_sys_a0_a4;
        //biosA0[0xa5] = psxBios_ReadSector;
-       //biosA0[0xa6] = psxBios_get_cd_status;
+       biosA0[0xa6] = psxBios_get_cd_status;
        //biosA0[0xa7] = psxBios_bufs_cb_0;
        //biosA0[0xa8] = psxBios_bufs_cb_1;
        //biosA0[0xa9] = psxBios_bufs_cb_2;
@@ -2953,7 +2972,7 @@ void psxBiosInit() {
        //biosB0[0x5a] = psxBios_sys_b0_5a;
        biosB0[0x5b] = psxBios_ChangeClearPad;
        biosB0[0x5c] = psxBios__card_status;
-       //biosB0[0x5d] = psxBios__card_wait;
+       biosB0[0x5d] = psxBios__card_wait;
 //*******************C0 CALLS****************************
        //biosC0[0x00] = psxBios_InitRCnt;
        //biosC0[0x01] = psxBios_InitException;
@@ -3033,7 +3052,9 @@ void psxBiosInit() {
 */
        // opcode HLE
        psxRu32ref(0x0000) = SWAPu32((0x3b << 26) | 4);
-       psxMu32ref(0x0000) = SWAPu32((0x3b << 26) | 0);
+       /* Whatever this does, it actually breaks CTR, even without the uninitiliazed memory patch. 
+       Normally games shouldn't read from address 0 yet they do. See explanation below in details. */
+       //psxMu32ref(0x0000) = SWAPu32((0x3b << 26) | 0);
        psxMu32ref(0x00a0) = SWAPu32((0x3b << 26) | 1);
        psxMu32ref(0x00b0) = SWAPu32((0x3b << 26) | 2);
        psxMu32ref(0x00c0) = SWAPu32((0x3b << 26) | 3);
@@ -3059,6 +3080,21 @@ void psxBiosInit() {
        psxHu32ref(0x1060) = SWAPu32(0x00000b88);
 
        hleSoftCall = FALSE;
+       
+       /*      Some games like R-Types, CTR, Fade to Black read from adress 0x00000000 due to uninitialized pointers.
+               See Garbage Area at Address 00000000h in Nocash PSX Specfications for more information.
+               R-type will work if PsxM[0] is non-zero. (Meaning that it should not be 00000003h as he implies).
+               Crash Team Racing will refuse to boot if psxM[2] and psx[3] are not set to 0.
+               Fade to Black can crash upon memory card access if byte 5 is set to the wrong value.
+       */
+       psxM[0] = SWAPu32(0x3C);
+       psxM[1] = SWAPu32(0x1A);
+       psxM[2] = SWAPu32(0x00);
+       psxM[3] = SWAPu32(0x00);
+       psxM[4] = SWAPu32(0x27);
+       psxM[5] = SWAPu32(0x5A);
+       psxM[6] = SWAPu32(0x0C);
+       psxM[7] = SWAPu32(0x80);
 }
 
 void psxBiosShutdown() {
@@ -3181,6 +3217,7 @@ void psxBiosException() {
 
        switch (psxRegs.CP0.n.Cause & 0x3c) {
                case 0x00: // Interrupt
+                       interrupt_r26=psxRegs.CP0.n.EPC;
 #ifdef PSXCPU_LOG
 //                     PSXCPU_LOG("interrupt\n");
 #endif
@@ -3279,7 +3316,6 @@ void psxBiosException() {
 void psxBiosFreeze(int Mode) {
        u32 base = 0x40000;
 
-       pad_stopped = 0;
        bfreezepsxMptr(jmp_int, u32);
        bfreezepsxMptr(pad_buf, int);
        bfreezepsxMptr(pad_buf1, char);
@@ -3294,4 +3330,6 @@ void psxBiosFreeze(int Mode) {
        bfreezel(&CurThread);
        bfreezes(FDesc);
        bfreezel(&card_active_chan);
+       bfreezel(&pad_stopped);
+       bfreezel(&heap_size);
 }