vdb.c

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

	"SRL",	     sllv,	"R%s,R%t,R%d",
	"SRA",	     sllv,	"R%s,R%t,R%d",
	"JMP",		0,	"(R%s)",
	"jal",	      jal,	"r%d,r%s",
	"special0A",	0,	mipscoxxx,
	"special0B",	0,	mipscoxxx,
	"SYSCALL",	0,	0,
	"BREAK",	0,	0,
	"special0E",	0,	mipscoxxx,
	"SYNC",		0,	0,
	"MOVW",		0,	"HI,R%d",
	"MOVW",		0,	"R%s,HI",
	"MOVW",		0,	"LO,R%d",
	"MOVW",		0,	"R%s,LO",
	"SLLV",	     sllv,	"R%s,R%t,R%d",
	"special15",	0,	mipscoxxx,
	"SRLV",	     sllv,	"R%s,R%t,R%d",
	"SRAV",	     sllv,	"R%s,R%t,R%d",
	"MUL",		0,	mipsrtrs,
	"MULU",		0,	mipsrtrs,
	"DIV",		0,	mipsrtrs,
	"DIVU",		0,	mipsrtrs,
	"special1C",	0,	mipscoxxx,
	"special1D",	0,	mipscoxxx,
	"DDIV",		0,	"R%s,R%t",
	"special1F",	0,	mipscoxxx,
	"ADD",	      add,	mipsalu3op,
	"ADDU",	      add,	mipsalu3op,
	"SUB",	      sub,	mipsalu3op,
	"SUBU",	      sub,	mipsalu3op,
	"AND",	      add,	mipsalu3op,
	"OR",	       or,	mipsalu3op,
	"XOR",	      add,	mipsalu3op,
	"NOR",	      nor,	mipsalu3op,
	"special28",	0,	mipscoxxx,
	"special29",	0,	mipscoxxx,
	"SGT",		0,	mipsalu3op,
	"SGTU",		0,	mipsalu3op,
	"special2C",	0,	mipscoxxx,
	"special2D",	0,	mipscoxxx,
	"special2E",	0,	mipscoxxx,
	"DSUBU",	0,	"R%s,R%t,R%d",
	"tge",		0,	mipscorsrt,
	"tgeu",		0,	mipscorsrt,
	"tlt",		0,	mipscorsrt,
	"tltu",		0,	mipscorsrt,
	"teq",		0,	mipscorsrt,
	"special35",	0,	mipscoxxx,
	"tne",		0,	mipscorsrt,
	"special37",	0,	mipscoxxx,
	"SLLV",	      sll,	"$%a,R%t,R%d",
	"special39",	0,	mipscoxxx,
	"SRLV",	      sll,	"$%a,R%t,R%d",
	"SRAV",	      sll,	"$%a,R%t,R%d",
	"SLLV",	     sl32,	"$%a,R%t,R%d",
	"special3D",	0,	mipscoxxx,
	"SRLV",	     sl32,	"$%a,R%t,R%d",
	"SRAV",	     sl32,	"$%a,R%t,R%d",
};

static Opcode ropcodes[32] = {
	"BLTZ",	   branch,	0,
	"BGEZ",	   branch,	0,
	"BLTZL",   branch,	0,
	"BGEZL",   branch,	0,
	"regimm04",	0,	mipscoxxx,
	"regimm05",	0,	mipscoxxx,
	"regimm06",	0,	mipscoxxx,
	"regimm07",	0,	mipscoxxx,
	"tgei",		0,	mipscorsi,
	"tgeiu",	0,	mipscorsi,
	"tlti",		0,	mipscorsi,
	"tltiu",	0,	mipscorsi,
	"teqi",		0,	mipscorsi,
	"regimm0D",	0,	mipscoxxx,
	"tnei",		0,	mipscorsi,
	"regimm0F",	0,	mipscoxxx,
	"BLTZAL",  branch,	0,
	"BGEZAL",  branch,	0,
	"BLTZALL", branch,	0,
	"BGEZALL", branch,	0,
	"regimm14",	0,	mipscoxxx,
	"regimm15",	0,	mipscoxxx,
	"regimm16",	0,	mipscoxxx,
	"regimm17",	0,	mipscoxxx,
	"regimm18",	0,	mipscoxxx,
	"regimm19",	0,	mipscoxxx,
	"regimm1A",	0,	mipscoxxx,
	"regimm1B",	0,	mipscoxxx,
	"regimm1C",	0,	mipscoxxx,
	"regimm1D",	0,	mipscoxxx,
	"regimm1E",	0,	mipscoxxx,
	"regimm1F",	0,	mipscoxxx,
};

static Opcode fopcodes[64] = {
	"ADD%f",	0,	mipsfp3,
	"SUB%f",	0,	mipsfp3,
	"MUL%f",	0,	mipsfp3,
	"DIV%f",	0,	mipsfp3,
	"sqrt.%f",	0,	mipscofp2,
	"ABS%f",	0,	mipsfp2,
	"MOV%f",	0,	mipsfp2,
	"NEG%f",	0,	mipsfp2,
	"finstr08",	0,	mipscoxxx,
	"finstr09",	0,	mipscoxxx,
	"finstr0A",	0,	mipscoxxx,
	"finstr0B",	0,	mipscoxxx,
	"round.w.%f",	0,	mipscofp2,
	"trunc.w%f",	0,	mipscofp2,
	"ceil.w%f",	0,	mipscofp2,
	"floor.w%f",	0,	mipscofp2,
	"finstr10",	0,	mipscoxxx,
	"finstr11",	0,	mipscoxxx,
	"finstr12",	0,	mipscoxxx,
	"finstr13",	0,	mipscoxxx,
	"finstr14",	0,	mipscoxxx,
	"finstr15",	0,	mipscoxxx,
	"finstr16",	0,	mipscoxxx,
	"finstr17",	0,	mipscoxxx,
	"finstr18",	0,	mipscoxxx,
	"finstr19",	0,	mipscoxxx,
	"finstr1A",	0,	mipscoxxx,
	"finstr1B",	0,	mipscoxxx,
	"finstr1C",	0,	mipscoxxx,
	"finstr1D",	0,	mipscoxxx,
	"finstr1E",	0,	mipscoxxx,
	"finstr1F",	0,	mipscoxxx,
	"cvt.s.%f",	0,	mipscofp2,
	"cvt.d.%f",	0,	mipscofp2,
	"cvt.e.%f",	0,	mipscofp2,
	"cvt.q.%f",	0,	mipscofp2,
	"cvt.w.%f",	0,	mipscofp2,
	"finstr25",	0,	mipscoxxx,
	"finstr26",	0,	mipscoxxx,
	"finstr27",	0,	mipscoxxx,
	"finstr28",	0,	mipscoxxx,
	"finstr29",	0,	mipscoxxx,
	"finstr2A",	0,	mipscoxxx,
	"finstr2B",	0,	mipscoxxx,
	"finstr2C",	0,	mipscoxxx,
	"finstr2D",	0,	mipscoxxx,
	"finstr2E",	0,	mipscoxxx,
	"finstr2F",	0,	mipscoxxx,
	"c.f.%f",	0,	mipscofpc,
	"c.un.%f",	0,	mipscofpc,
	"CMPEQ%f",	0,	mipsfpc,
	"c.ueq.%f",	0,	mipscofpc,
	"c.olt.%f",	0,	mipscofpc,
	"c.ult.%f",	0,	mipscofpc,
	"c.ole.%f",	0,	mipscofpc,
	"c.ule.%f",	0,	mipscofpc,
	"c.sf.%f",	0,	mipscofpc,
	"c.ngle.%f",	0,	mipscofpc,
	"c.seq.%f",	0,	mipscofpc,
	"c.ngl.%f",	0,	mipscofpc,
	"CMPGT%f",	0,	mipsfpc,
	"c.nge.%f",	0,	mipscofpc,
	"CMPGE%f",	0,	mipsfpc,
	"c.ngt.%f",	0,	mipscofpc,
};

static char *cop0regs[32] = {
	"INDEX", "RANDOM", "TLBPHYS", "EntryLo0",
	"CONTEXT", "PageMask", "Wired",	"Error",
	"BADVADDR", "Count", "TLBVIRT", "Compare",
	"STATUS", "CAUSE", "EPC", "PRID",
	"Config", "LLadr", "WatchLo", "WatchHi",
	"20", "21", "22", "23",
	"24", "25", "26", "CacheErr",
	"TagLo", "TagHi", "ErrorEPC", "31"
};

static char fsub[16] = {
	'F', 'D', 'e', 'q', 'W', '?', '?', '?',
	'?', '?', '?', '?', '?', '?', '?', '?'
};

static char *cacheps[] = {
	"I", "D", "SI", "SD"
};

static char *cacheop[] = {
	"IWBI", "ILT", "IST", "CDE", "HI", "HWBI", "HWB", "HSV"
};

static void
format(char *mnemonic, Instr *i, char *f)
{
	if (mnemonic)
		format(0, i, mnemonic);
	if (f == 0)
		return;
	if (mnemonic)
		if (i->curr < i->end)
			*i->curr++ = '\t';
	for ( ; *f && i->curr < i->end; f++) {
		if (*f != '%') {
			*i->curr++ = *f;
			continue;
		}
		switch (*++f) {

		case 's':
			bprint(i, "%d", i->rs);
			break;

		case 't':
			bprint(i, "%d", i->rt);
			break;

		case 'd':
			bprint(i, "%d", i->rd);
			break;

		case 'a':
			bprint(i, "%d", i->sa);
			break;

		case 'l':
			bprint(i, "%lx(R%d)",i->immediate, i->rs);
			break;

		case 'i':
			bprint(i, "$%lx", i->immediate);
			break;

		case 'u':
			i->curr += symoff(i->curr, i->end-i->curr, i->immediate, CANY);
			bprint(i, "(SB)");
			break;

		case 'j':
			i->curr += symoff(i->curr, i->end-i->curr,
				(i->target<<2)|(i->addr & 0xF0000000), CANY);
			bprint(i, "(SB)");
			break;

		case 'b':
			i->curr += symoff(i->curr, i->end-i->curr,
				(i->immediate<<2)+i->addr+4, CANY);
			break;

		case 'c':
			bprint(i, "$%lx", i->cofun);
			break;

		case 'w':
			bprint(i, "[%lux]", i->w0);
			break;

		case 'm':
			bprint(i, "M(%s)", cop0regs[i->rd]);
			break;

		case 'f':
			*i->curr++ = fsub[i->rs & 0x0F];
			break;

		case 'C':
			bprint(i, "%s%s", cacheps[i->rt & 3], cacheop[(i->rt>>2) & 7]);
			break;

		case '\0':
			*i->curr++ = '%';
			return;

		default:
			bprint(i, "%%%c", *f);
			break;
		}
	}
	*i->curr = 0;
}

static void
copz(int cop, Instr *i)
{
	char *f, *m, buf[16];

	m = buf;
	f = "%t,%d";
	switch (i->rs) {

	case 0:
		sprint(buf, "mfc%d", cop);
		break;

	case 2:
		sprint(buf, "cfc%d", cop);
		break;

	case 4:
		sprint(buf, "mtc%d", cop);
		break;

	case 6:
		sprint(buf, "ctc%d", cop);
		break;

	case 8:
		f = "%b";
		switch (i->rt) {

		case 0:
			sprint(buf, "bc%df", cop);
			break;

		case 1:
			sprint(buf, "bc%dt", cop);
			break;

		case 2:
			sprint(buf, "bc%dfl", cop);
			break;

		case 3:
			sprint(buf, "bc%dtl", cop);
			break;

		default:
			sprint(buf, "cop%d", cop);
			f = mipscoxxx;
			break;
		}
		break;

	default:
		sprint(buf, "cop%d", cop);
		if (i->rs & 0x10)
			f = "function %c";
		else
			f = mipscoxxx;
		break;
	}
	format(m, i, f);
}

static void
cop0(Instr *i)
{
	char *m = 0;

	if (i->rs < 8) {
		switch (i->rs) {

		case 0:
		case 1:
			format("MOVW", i, "%m,R%t");
			return;

		case 4:
		case 5:
			format("MOVW", i, "R%t,%m");
			return;
		}
	}
	else if (i->rs >= 0x10) {
		switch (i->cofun) {
	
		case 1:
			m = "TLBR";
			break;
	
		case 2:
			m = "TLBWI";
			break;
	
		case 6:
			m = "TLBWR";
			break;
	
		case 8:
			m = "TLBP";
			break;
	
		case 16:
			m = "RFE";
			break;
	
		case 32:
			m = "ERET";
			break;
		}
		if (m) {
			format(m, i, 0);
			return;
		}
	}
	copz(0, i);
}

static void
cop1(Instr *i)
{
	char *m = "MOVW";

	switch (i->rs) {

	case 0:
		format(m, i, "F%d,R%t");
		return;

	case 2:
		format(m, i, "FCR%d,R%t");
		return;

	case 4:
		format(m, i, "R%t,F%d");
		return;

	case 6:
		format(m, i, "R%t,FCR%d");
		return;

	case 8:
		switch (i->rt) {

		case 0:
			format("BFPF", i, "%b");
			return;

		case 1:
			format("BFPT", i, "%b");
			return;
		}
		break;
	}
	copz(1, i);
}

static int
printins(Map *map, uvlong pc, char *buf, int n)
{
	Instr i;
	Opcode *o;
	uchar op;

	i.curr = buf;
	i.end = buf+n-1;
	mymap = map;
	if (mkinstr(pc, &i) < 0)
		return -1;
	switch (i.op) {

	case 0x00:					/* SPECIAL */
		o = sopcodes;
		op = i.function;
		break;

	case 0x01:					/* REGIMM */
		o = ropcodes;
		op = i.rt;
		break;

	case 0x10:					/* COP0 */
		cop0(&i);
		return i.size*4;

	case 0x11:					/* COP1 */
		if (i.rs & 0x10) {
			o = fopcodes;
			op = i.function;
			break;
		}
		cop1(&i);
		return i.size*4;

	case 0x12:					/* COP2 */
	case 0x13:					/* COP3 */
		copz(i.op-0x10, &i);
		return i.size*4;

	default:
		o = opcodes;
		op = i.op;
		break;
	}
	if (o[op].f)
		(*o[op].f)(&o[op], &i);
	else
		format(o[op].mnemonic, &i, o[op].ken);
	return i.size*4;
}

extern	int	_mipscoinst(Map *, uvlong, char*, int);

	/* modifier 'I' toggles the default disassembler type */
static int
mipsinst(Map *map, uvlong pc, char modifier, char *buf, int n)
{
	if ((asstype == AMIPSCO && modifier == 'i')
		|| (asstype == AMIPS && modifier == 'I'))
		return _mipscoinst(map, pc, buf, n);
	else
		return printins(map, pc, buf, n);
}

static int
mipsdas(Map *map, uvlong pc, char *buf, int n)
{
	Instr i;

	i.curr = buf;
	i.end = buf+n;
	mymap = map;
	if (mkinstr(pc, &i) < 0)
		return -1;
	if (i.end-i.curr > 8)
		i.curr = _hexify(buf, i.w0, 7);
	if (i.size == 2 && i.end-i.curr > 9) {
		*i.curr++ = ' ';
		i.curr = _hexify(i.curr, i.w1, 7);
	}
	*i.curr = 0;
	return i.size*4;
}

static int
mipsinstlen(Map *map, uvlong pc)
{
	Instr i;

	mymap = map;
	if (mkinstr(pc, &i) < 0)
		return -1;
	return i.size*4;
}

static int
mipsfoll(Map *map, uvlong pc, Rgetter rget, uvlong *foll)
{
	ulong w, l;
	char buf[8];
	Instr i;

	mymap = map;
	if (mkinstr(pc, &i) < 0)
		return -1;
	w = i.w0;
	if((w&0xF3600000) == 0x41000000){	/* branch on coprocessor */
    Conditional:
		foll[0] = pc+8;
		l = ((w&0xFFFF)<<2);
		if(w & 0x8000)
			l |= 0xFFFC0000;
		foll[1] = pc+4 + l;
		return 2;
	}

	l = (w&0xFC000000)>>26;
	switch(l){
	case 0:		/* SPECIAL */
		if((w&0x3E) == 0x08){	/* JR, JALR */
			sprint(buf, "R%ld", (w>>21)&0x1F);
			foll[0] = (*rget)(map, buf);
			return 1;
		}
		foll[0] = pc+i.size*4;
		return 1;
	case 0x30:	/* Load-Linked followed by NOP, STC */
		foll[0] = pc+12;
		return 1;
	case 1:		/* BCOND */
	case 4:		/* BEQ */
	case 20:	/* BEQL */
	case 5:		/* BNE */
	case 21:	/* BNEL */
	case 6:		/* BLEZ */
	case 22:	/* BLEZL */
	case 7:		/* BGTZ */
	case 23:	/* BGTZL */
		goto Conditional;
	case 2:		/* J */
	case 3:		/* JAL */
		foll[0] = (pc&0xF0000000) | ((w&0x03FFFFFF)<<2);
		return 1;
	}

	foll[0] = pc+i.size*4;
	return 1;
}