arm9es.cpp

一个任天堂掌上游戏机NDS的源代码

    else prn.print(str,72*6,32,0x00FFFFFF);

    a=(reg.cpsr&CPSR_T)>>5;  sprintf(str,"T: %d",a);
    if(r15old!=r15orig)
        if(a!=dbgoldf[5]) { dbgoldf[5]=a; fchanged[5]=1; } else fchanged[5]=0;
    if(fchanged[5]) prn.print(str,72*6,40,0x000000FF);
    else prn.print(str,72*6,40,0x00FFFFFF);

    if(r15old!=r15orig) r15old=r15orig;

    }

    GUI->subwinRefresh(dbgwinID);
}

// Function the disassembler will use to read memory
u32 ARM9ES::rdWhelper(u32 addr) { return MMU->rdW(addr); }

// Save registers, and switch processor modes
void ARM9ES::modeSwitch(int in, int out)
{
    //---Save state
    reg.r0 = reg.r[0]; reg.r1 = reg.r[1];
    reg.r2 = reg.r[2]; reg.r3 = reg.r[3];
    reg.r4 = reg.r[4]; reg.r5 = reg.r[5];
    reg.r6 = reg.r[6]; reg.r7 = reg.r[7];

    if(in == MODE_FIQ)
    {
	reg.r8fiq = reg.r[8];   reg.r9fiq = reg.r[9];
	reg.r10fiq = reg.r[10]; reg.r11fiq = reg.r[11];
	reg.r12fiq = reg.r[12];
    } else {
	reg.r8 = reg.r[8];   reg.r9 = reg.r[9];
	reg.r10 = reg.r[10]; reg.r11 = reg.r[11];
	reg.r12 = reg.r[12];
    }
    switch(in)
    {
	case MODE_USR:
	case MODE_SYS: reg.r13 = reg.r[13]; reg.r14 = reg.r[14]; break;
	case MODE_IRQ: reg.r13irq = reg.r[13]; reg.r14irq = reg.r[14]; break;
	case MODE_FIQ: reg.r13fiq = reg.r[13]; reg.r14fiq = reg.r[14]; break;
	case MODE_SVC: reg.r13svc = reg.r[13]; reg.r14svc = reg.r[14]; break;
	case MODE_ABT: reg.r13abt = reg.r[13]; reg.r14abt = reg.r[14]; break;
	case MODE_UND: reg.r13und = reg.r[13]; reg.r14und = reg.r[14]; break;
    }
    reg.r15 = reg.r[15];
    
    //---Switch to new mode
    if(out == MODE_FIQ)
    {
	reg.r[8] = reg.r8fiq;   reg.r[9] = reg.r9fiq;
	reg.r[10] = reg.r10fiq; reg.r[11] = reg.r11fiq;
	reg.r[12] = reg.r12fiq;
    } else {
	reg.r[8] = reg.r8;   reg.r[9] = reg.r9;
	reg.r[10] = reg.r10; reg.r[11] = reg.r11;
	reg.r[12] = reg.r12;
    }
    switch(out)
    {
	case MODE_USR:
	case MODE_SYS: reg.r[13] = reg.r13; reg.r[14] = reg.r14; break;
	case MODE_IRQ: reg.r[13] = reg.r13irq; reg.r[14] = reg.r14irq; break;
	case MODE_FIQ: reg.r[13] = reg.r13fiq; reg.r[14] = reg.r14fiq; break;
	case MODE_SVC: reg.r[13] = reg.r13svc; reg.r[14] = reg.r14svc; break;
	case MODE_ABT: reg.r[13] = reg.r13abt; reg.r[14] = reg.r14abt; break;
	case MODE_UND: reg.r[13] = reg.r13und; reg.r[14] = reg.r14und; break;
    }
    
    reg.curmode = out;
    cpsrUpdate();
}

// Update the CPSR based on the flags[] array
void ARM9ES::cpsrUpdate()
{
    if(reg.flags[FLAG_N]) reg.cpsr|=CPSR_N; else reg.cpsr&=(~CPSR_N);
    if(reg.flags[FLAG_Z]) reg.cpsr|=CPSR_Z; else reg.cpsr&=(~CPSR_Z);
    if(reg.flags[FLAG_C]) reg.cpsr|=CPSR_C; else reg.cpsr&=(~CPSR_C);
    if(reg.flags[FLAG_V]) reg.cpsr|=CPSR_V; else reg.cpsr&=(~CPSR_V);
    if(reg.flags[FLAG_T]) reg.cpsr|=CPSR_T; else reg.cpsr&=(~CPSR_T);
    if(reg.flags[FLAG_Q]) reg.cpsr|=CPSR_Q; else reg.cpsr&=(~CPSR_Q);
    reg.cpsr &= ~CPSR_M;
    reg.cpsr |= modeToCpsrLUT[reg.curmode];
}

// Split the CPSR into the flags[] array
void ARM9ES::cpsrSplit()
{
    reg.flags[FLAG_N]=(reg.cpsr>>31)&1;
    reg.flags[FLAG_Z]=(reg.cpsr>>30)&1;
    reg.flags[FLAG_C]=(reg.cpsr>>29)&1;
    reg.flags[FLAG_V]=(reg.cpsr>>28)&1;
    reg.flags[FLAG_T]=(reg.cpsr>>5)&1;
    reg.flags[FLAG_Q]=(reg.cpsr>>27)&1;

    modeSwitch(reg.curmode, modeFromCpsrLUT[reg.cpsr&15]);
}

// Add to the internal clock
void ARM9ES::clockAdd(int cyc)
{
    reg.clkcount += cyc;
}

// Toggle a breakpoint on or off at a specific address
void ARM9ES::dbgBkptToggle(u32 addr)
{
    if(bkpts.find(addr) != bkpts.end()) bkpts.erase(addr);
    else bkpts[addr]=1;

    status();
}

// Return the map of breakpoint addresses to states
std::map<u32, int> ARM9ES::dbgBkptGet()
{
    return bkpts;
}

// Work out how many bits in a 16-bit value are set to 1
// Used by the LDM/STM opcodes
// ACK: Donald Knuth (Sidesum algorithm)
int ARM9ES::ssum16(u16 val)
{
    int res=val;
    res=((res>>1)&0x5555)+(res&0x5555);
    res=((res>>2)&0x3333)+(res&0x3333);
    res=((res>>4)&0x0F0F)+(res&0x0F0F);
    res=((res>>8)&0x00FF)+(res&0x00FF);
    return res;
}

// Dispatch
// TODO: Optimise the dispatch loop, it's damned slow

int ARM9ES::exec(int cycles)
{
    uint64_t stamp = reg.clkcount+cycles, start = reg.clkcount;
    do {	    
	if(bkpts.find(reg.r[15]) != bkpts.end())
	{
	    switch(bkpts[reg.r[15]])
	    {
		case 1:
		    bkpts[reg.r[15]]=2;
                    char str[20];
                    sprintf(str, "PC=%08X", reg.r[15]);
                    Logger::log(pName) << "Breakpoint encountered at " << str;
                    return -(reg.clkcount-start);
		case 2:
		    bkpts[reg.r[15]]=1;
		    break;
	    }
	}
	if(reg.flags[FLAG_T])
	{
	    reg.curop = (u32)MMU->rdH(reg.r[15]);
	    reg.r[15] += 2;

	    reg.clkcount += TLUT[(reg.curop&TMSK_OP)>>TSHFT_OP]();
	    
#ifdef ARM9ES_DEBUG
	    cpsrUpdate();
            reg.r[15]+=2; fwrite(reg.r, 4, 17, dumpfile); reg.r[15]-=2;
#endif	    
	    
	} else {
            reg.curop = MMU->rdW(reg.r[15]);
	    //char str[64];
	    //sprintf(str, "%08X: %08X | ", reg.r[15], reg.curop);
	    //Logger::log(pluginName) << str << dasm.disasm(reg.curop);
	    
	    reg.r[15] += 4;
	    
            if(condLUT[(reg.curop&MSK_COND)>>SHFT_COND]())
            {
                reg.clkcount += OLUT[((reg.curop&MSK_OP)>>SHFT_OPH)|
                                     ((reg.curop&MSK_FUNC)>>SHFT_FUNC)]();
            }
            else reg.clkcount++;
	    
#ifdef ARM9ES_DEBUG
	    cpsrUpdate();
            reg.r[15]+=4; fwrite(reg.r, 4, 17, dumpfile); reg.r[15]-=4;
#endif	    
	    
	}
    } while(reg.clkcount < stamp);
    return reg.clkcount - start;
}

// CPU is interrupted; set up the CPU state for the int handler
void ARM9ES::interrupt(int type)
{
    // Type ignored for now, IRQ assumed
    reg.flags[FLAG_T]=0;
    cpsrUpdate();
    reg.cpsr |= CPSR_I;
    
    reg.r14irq = reg.r[15];
    reg.spsr[MODE_IRQ] = reg.cpsr;
    modeSwitch(reg.curmode, MODE_IRQ);
    
#ifdef ARM_HIGH_VECTORS
    reg.r[15] = 0xFFFF0018;
#else
    reg.r[15] = 0x00000018;
#endif
    
}

void ARM9ES::setPC(u32 pc)
{
    reg.r[15] = pc;
}

//---Exceptional opcode handlers-------------------------------------------
// NOTE: As of right now, these do nothing; they are there such that the
//       opcodes can safely call them if a problem occurs. 

OPC opUND()
{
    char str[80];
    sprintf(str, " at %08X: %08X", reg.r[15], reg.curop);
    //Logger::log(pluginName) << "Undefined opcode" << str;
    return 1;
}

OPC opUNP()
{
    char str[80];
    sprintf(str, " at %08X: %08X", reg.r[15], reg.curop);
    //Logger::log(pluginName) << "Unpredictable opcode" << str;
    return 1;
}

OPC opUNI()
{
    char str[80];
    sprintf(str, " at %08X: %08X", reg.r[15], reg.curop);
    //Logger::log(pluginName) << "Unimplemented opcode" << str;
    return 1;
}

OPC opUNL()
{
    // Would act as cache filler
    return 1;
}

//---Plugin Support--------------------------------------------------------
// Retrieve Plugin class from outside
// Parameters: plg   - Address of a pointer to a Plugin class to 'new'
//             name  - FQPN of plugin as listed in INI file
//             req   - Pointer to PluginRequest API function
//             unreq - Pointer to PluginUnrequest API function
EXPORTFUNC void getPlugin(Plugin **plg,
                          std::string name,
                          REQPTR req, UNREQPTR unreq)
{
    // Initialise a new Test plugin at the parameter
    *plg = new ARM9ES(name, req, unreq);
}

// Provide plugin version information
PLUGININFO *ARM9ES::getinfo()
{
    return &pInfo;
}

// Release plugin from outside
void ARM9ES::release()
{
    // Delete the Test plugin that was 'new'd in getPlugin.
    delete this;
}

/*** EOF: arm9es.cpp *****************************************************/