#include "libultra_internal.h"
#include <macros.h>

#define PIF_ADDR_START (void *) 0x1FC007FC

typedef struct {
    u32 instr00;
    u32 instr01;
    u32 instr02;
    u32 instr03;
} exceptionPreamble;

u32 D_80365CD0; // maybe initialized?
u64 osClockRate = 62500000;
u32 D_80334808 = 0;

#define EXCEPTION_TLB_MISS 0x80000000
#define EXCEPTION_XTLB_MISS 0x80000080
#define EXCEPTION_CACHE_ERROR 0x80000100
#define EXCEPTION_GENERAL 0x80000180

extern u32 osResetType;
extern exceptionPreamble __osExceptionPreamble;

void osInitialize(void) {
    u32 sp34;
    u32 sp30 = 0;
    UNUSED u32 sp2c;
    D_80365CD0 = TRUE;
    __osSetSR(__osGetSR() | 0x20000000);
    __osSetFpcCsr(0x01000800);
    while (__osSiRawReadIo(PIF_ADDR_START, &sp34)) {
        ;
    }
    while (__osSiRawWriteIo(PIF_ADDR_START, sp34 | 8)) {
        ;
    }
    *(exceptionPreamble *) EXCEPTION_TLB_MISS = __osExceptionPreamble;
    *(exceptionPreamble *) EXCEPTION_XTLB_MISS = __osExceptionPreamble;
    *(exceptionPreamble *) EXCEPTION_CACHE_ERROR = __osExceptionPreamble;
    *(exceptionPreamble *) EXCEPTION_GENERAL = __osExceptionPreamble;
    osWritebackDCache((void *) 0x80000000,
                      EXCEPTION_GENERAL + sizeof(exceptionPreamble) - EXCEPTION_TLB_MISS);
    osInvalICache((void *) 0x80000000,
                  EXCEPTION_GENERAL + sizeof(exceptionPreamble) - EXCEPTION_TLB_MISS);
    osMapTLBRdb();
    osPiRawReadIo(4, &sp30);
    sp30 &= ~0xf;
    if (sp30) {
        osClockRate = sp30;
    }
    osClockRate = osClockRate * 3 / 4;
    if (osResetType == RESET_TYPE_COLD_RESET) {
        bzero(osAppNmiBuffer, sizeof(osAppNmiBuffer));
    }
}