newcpu.c

又一个游戏模拟器,著名ARC模拟器源码,包括多个平台

{
    MakeSR();
    if (!regs.s) {
		regs.usp = m68k_areg(regs, 7);
		m68k_areg(regs, 7) = regs.m ? regs.msp : regs.isp;
		regs.s = 1;
    }
    if (nr == 2 || nr == 3) {
		int i;
		/* @@@ this is probably wrong (?) */
		for (i = 0 ; i < 12 ; i++) {
			m68k_areg(regs, 7) -= 2;
			cpu_writemem24_word (m68k_areg(regs, 7), 0);
		}
		m68k_areg(regs, 7) -= 2;
		cpu_writemem24_word(m68k_areg(regs, 7), 0xa000 + nr * 4);
	} else if (nr ==5 || nr == 6 || nr == 7 || nr == 9) {
		m68k_areg(regs, 7) -= 4;
		cpu_writemem24_dword (m68k_areg(regs, 7), oldpc);
		m68k_areg(regs, 7) -= 2;
		cpu_writemem24_word (m68k_areg(regs, 7), 0x2000 + nr * 4);
	} else if (regs.m && nr >= 24 && nr < 32) {
		m68k_areg(regs, 7) -= 2;
		cpu_writemem24_word (m68k_areg(regs, 7), nr * 4);
		m68k_areg(regs, 7) -= 4;
		cpu_writemem24_dword (m68k_areg(regs, 7), m68k_getpc ());
		m68k_areg(regs, 7) -= 2;
		cpu_writemem24_word (m68k_areg(regs, 7), regs.sr);
		regs.sr |= (1 << 13);
		regs.msp = m68k_areg(regs, 7);
		m68k_areg(regs, 7) = regs.isp;
		m68k_areg(regs, 7) -= 2;
		cpu_writemem24_word (m68k_areg(regs, 7), 0x1000 + nr * 4);
	} else {
		m68k_areg(regs, 7) -= 2;
		cpu_writemem24_word (m68k_areg(regs, 7), nr * 4);
	}
    m68k_areg(regs, 7) -= 4;
    cpu_writemem24_dword (m68k_areg(regs, 7), m68k_getpc ());
	//kludge_me_do:
    m68k_areg(regs, 7) -= 2;
    cpu_writemem24_word (m68k_areg(regs, 7), regs.sr);
    m68k_setpc (cpu_readmem24_dword (regs.vbr + 4*nr));
    regs.t1 = regs.t0 = regs.m = 0;
}


static int caar, cacr;

int m68k_move2c (int regno, UINT32 *regp)
{
	switch (regno) {
	case 0: regs.sfc = *regp & 7; break;
	case 1: regs.dfc = *regp & 7; break;
	case 2: cacr = *regp & 0x3; break;	/* ignore C and CE */
	case 0x800: regs.usp = *regp; break;
	case 0x801: regs.vbr = *regp; break;
	case 0x802: caar = *regp &0xfc; break;
	case 0x803: regs.msp = *regp; if (regs.m == 1) m68k_areg(regs, 7) = regs.msp; break;
	case 0x804: regs.isp = *regp; if (regs.m == 0) m68k_areg(regs, 7) = regs.isp; break;
	default:
		op_illg (0x4E7B);
		return 0;
	}
    return 1;
}

int m68k_movec2 (int regno, UINT32 *regp)
{
	switch (regno) {
	case 0: *regp = regs.sfc; break;
	case 1: *regp = regs.dfc; break;
	case 2: *regp = cacr; break;
	case 0x800: *regp = regs.usp; break;
	case 0x801: *regp = regs.vbr; break;
	case 0x802: *regp = caar; break;
	case 0x803: *regp = regs.m == 1 ? m68k_areg(regs, 7) : regs.msp; break;
	case 0x804: *regp = regs.m == 0 ? m68k_areg(regs, 7) : regs.isp; break;
	default:
		op_illg (0x4E7A);
		return 0;
	}
    return 1;
}

static DEF_INLINE int
div_unsigned(UINT32 src_hi, UINT32 src_lo, UINT32 div, UINT32 *quot, UINT32 *rem)
{
	UINT32 q = 0, cbit = 0;
	int i;
	
	if (div <= src_hi) {
		return 1;
	}
	for (i = 0 ; i < 32 ; i++) {
		cbit = src_hi & 0x80000000ul;
		src_hi <<= 1;
		if (src_lo & 0x80000000ul) src_hi++;
		src_lo <<= 1;
		q = q << 1;
		if (cbit || div <= src_hi) {
			q |= 1;
			src_hi -= div;
		}
	}
	*quot = q;
	*rem = src_hi;
	return 0;
}

void m68k_divl (UINT32 opcode, UINT32 src, UINT16 extra, CPTR oldpc)
{
	(void)(opcode);
    if (src == 0) {
		Exception (5, oldpc);
		return;
    }
    if (extra & 0x800) {
		/* signed variant */
		INT64 a = (INT64)(INT32)m68k_dreg(regs, (extra >> 12) & 7);
		INT64 quot, rem;
		
		if (extra & 0x400) {
			a &= 0xffffffffu;
			a |= (INT64)m68k_dreg(regs, extra & 7) << 32;
		}
		rem = a % (INT64)(INT32)src;
		quot = a / (INT64)(INT32)src;
		if ((quot & (UINT64)(0xffffffff80000000)) != 0
			&& (quot & (UINT64)(0xffffffff80000000)) != (UINT64)(0xffffffff80000000))
		{
			SET_VFLG (1);
			SET_NFLG (1);
			SET_CFLG (0);
		} else {
			if (((INT32)rem < 0) != ((INT64)a < 0)) rem = -rem;
			SET_VFLG (0);
			SET_CFLG (0);
			SET_ZFLG (((INT32)quot) == 0);
			SET_NFLG (((INT32)quot) < 0);
			m68k_dreg(regs, extra & 7) = rem;
			m68k_dreg(regs, (extra >> 12) & 7) = quot;
		}
    } else {
		/* unsigned */
		UINT64 a = (UINT64)(INT32)m68k_dreg(regs, (extra >> 12) & 7);
		UINT64 quot, rem;
		
		if (extra & 0x400) {
			a &= 0xffffffffu;
			a |= (UINT64)m68k_dreg(regs, extra & 7) << 32;
		}
		rem = a % (UINT64)src;
		quot = a / (UINT64)src;
		if (quot > 0xffffffffu) {
			SET_VFLG (1);
			SET_NFLG (1);
			SET_CFLG (0);
		} else {
			SET_VFLG (0);
			SET_CFLG (0);
			SET_ZFLG (((INT32)quot) == 0);
			SET_NFLG (((INT32)quot) < 0);
			m68k_dreg(regs, extra & 7) = rem;
			m68k_dreg(regs, (extra >> 12) & 7) = quot;
		}
    }
}

static DEF_INLINE void
mul_unsigned(UINT32 src1, UINT32 src2, UINT32 *dst_hi, UINT32 *dst_lo)
{
	UINT32 r0 = (src1 & 0xffff) * (src2 & 0xffff);
	UINT32 r1 = ((src1 >> 16) & 0xffff) * (src2 & 0xffff);
	UINT32 r2 = (src1 & 0xffff) * ((src2 >> 16) & 0xffff);
	UINT32 r3 = ((src1 >> 16) & 0xffff) * ((src2 >> 16) & 0xffff);
	UINT32 lo;
	
	lo = r0 + ((r1 << 16) & 0xffff0000ul);
	if (lo < r0) r3++;
	r0 = lo;
	lo = r0 + ((r2 << 16) & 0xffff0000ul);
	if (lo < r0) r3++;
	r3 += ((r1 >> 16) & 0xffff) + ((r2 >> 16) & 0xffff);
	*dst_lo = lo;
	*dst_hi = r3;
}

void m68k_mull (UINT32 opcode, UINT32 src, UINT16 extra)
{
	(void)(opcode);
    if (extra & 0x800) {
		/* signed variant */
		UINT64 a = (INT64)(INT32)m68k_dreg(regs, (extra >> 12) & 7);
		
		a *= (INT64)(INT32)src;
		SET_VFLG (0);
		SET_CFLG (0);
		SET_ZFLG (a == 0);
		SET_NFLG (a < 0);
		if (extra & 0x400)
			m68k_dreg(regs, extra & 7) = a >> 32;
		else if ((a & (UINT64)(0xffffffff80000000)) != 0
			&& (a & (UINT64)(0xffffffff80000000)) != (UINT64)(0xffffffff80000000))
		{
			SET_VFLG (1);
		}
		m68k_dreg(regs, (extra >> 12) & 7) = (UINT32)a;
    } else {
		/* unsigned */
		UINT64 a = (UINT64)(UINT32)m68k_dreg(regs, (extra >> 12) & 7);
		
		a *= (UINT64)src;
		SET_VFLG (0);
		SET_CFLG (0);
		SET_ZFLG (a == 0);
		SET_NFLG (((UINT64)a) < 0);
		if (extra & 0x400)
			m68k_dreg(regs, extra & 7) = a >> 32;
		else if ((a & (UINT64)(0xffffffff00000000)) != 0) {
			SET_VFLG (1);
		}
		m68k_dreg(regs, (extra >> 12) & 7) = (UINT32)a;
    }
}
static char* ccnames[] =
{ "T ","F ","HI","LS","CC","CS","NE","EQ",
"VC","VS","PL","MI","GE","LT","GT","LE" };

void Reset68020 (void)
{
    m68k_areg (regs, 7) = cpu_readmem24_dword(0);
    m68k_setpc (cpu_readmem24_dword(4));
    regs.s = 1;
    regs.m = 0;
    regs.stopped = 0;
    regs.t1 = 0;
    regs.t0 = 0;
    SET_ZFLG (0);
    SET_XFLG (0);
    SET_CFLG (0);
    SET_VFLG (0);
    SET_NFLG (0);
    regs.intmask = 7;
    regs.vbr = regs.sfc = regs.dfc = 0;
	regs.sr=0x2700;
	MakeFromSR();
}

unsigned long op_illg (UINT32 opcode)
{
	(void)(opcode);
    
    Exception (4,0);
    return 4;
}

static int n_insns = 0, n_spcinsns = 0;

static CPTR last_trace_ad = 0;

void m68k_disasm (CPTR addr, CPTR *nextpc, int cnt, output_func_ptr debug_out)
{
    CPTR newpc = 0;
    m68kpc_offset = addr - m68k_getpc ();
    while (cnt-- > 0) {
		char instrname[20],*ccpt;
		int opwords;
		UINT32 opcode;
		struct mnemolookup *lookup;
		struct instr *dp;
		(*debug_out) ("%08lx: ", m68k_getpc () + m68kpc_offset);
		for (opwords = 0; opwords < 5; opwords++){
			(*debug_out) ("%04x ", get_iword_1 (m68kpc_offset + opwords*2));
		}
		opcode = get_iword_1 (m68kpc_offset);
		m68kpc_offset += 2;
		if (cpufunctbl[opcode] == op_illg_1) {
			opcode = 0x4AFC;
		}
		dp = table68k + opcode;
		for (lookup = lookuptab;lookup->mnemo != dp->mnemo; lookup++)
			;
		
		strcpy (instrname, lookup->name);
		ccpt = strstr (instrname, "cc");
		if (ccpt != 0) {
			strncpy (ccpt, ccnames[dp->cc], 2);
		}
		(*debug_out) ("%s", instrname);
		switch (dp->size){
		case sz_byte: (*debug_out) (".B "); break;
		case sz_word: (*debug_out) (".W "); break;
		case sz_long: (*debug_out) (".L "); break;
		default: (*debug_out) ("   "); break;
		}
		
		if (dp->suse) {
			newpc = m68k_getpc () + m68kpc_offset;
			newpc += ShowEA (dp->sreg, dp->smode, dp->size, 0, debug_out);
		}
		if (dp->suse && dp->duse)
			(*debug_out) (",");
		if (dp->duse) {
			newpc = m68k_getpc () + m68kpc_offset;
			newpc += ShowEA (dp->dreg, dp->dmode, dp->size, 0, debug_out);
		}
		if (ccpt != 0) {
			if (cctrue(dp->cc))
				(*debug_out) (" == %08lx (TRUE)", newpc);
			else
				(*debug_out) (" == %08lx (FALSE)", newpc);
		} else if ((opcode & 0xff00) == 0x6100) /* BSR */
			(*debug_out) (" == %08lx", newpc);
		(*debug_out) ("\n");
    }
    if (nextpc)
		*nextpc = m68k_getpc () + m68kpc_offset;
}

void Execute68020(int c)
{
	UINT32 opcode;

	cycles = (c>>4);

    while ( cycles )
	{
		opcode = get_iword (0);
		cycles -= (*cpufunctbl[opcode])(opcode);
		opcode = get_iword (0);
		cycles -= (*cpufunctbl[opcode])(opcode);
		opcode = get_iword (0);
		cycles -= (*cpufunctbl[opcode])(opcode);
		opcode = get_iword (0);
		cycles -= (*cpufunctbl[opcode])(opcode);
	}
}

void Interrupt68020(int level)
{
	MakeSR();
	if(level>=((regs.sr&0xf00)>>8)) Exception(level+24,regs.pc);
}

void Stop68020(void)
{
   cycles=0;
}