cgen64.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

				l = t;
			}
			break;
		case IMM(0, 1):
			if(dr)
				t = nn;
			else
				t = regpair(Z, n);
			sugen(l, t, 8);
			l = t;
			break;
		case IMM(1, 0):
			if(n->op == OSUB && l->op == OCONST && hi64v(l) == 0) {
				lri = IMM(0, 0);
				goto bin00;
			}
			if(dr)
				t = nn;
			else
				t = regpair(Z, n);
			sugen(r, t, 8);
			r = t;
			break;
		case IMM(1, 1):
			break;
		}

#define	WW(l, r)	((l) | ((r) << 2))
		d = Z;
		dt = nn->type;
		nn->type = types[TLONG];

		switch(lri) {
		case IMM(0, 0):
			biggen(l, r, Z, 0, binop00, args);
			break;
		case IMM(0, 1):
			switch(ri) {
			case WNONE:
				diag(r, "bad whatof\n");
				break;
			case WCONST:
				biggen(l, r, Z, 0, optab[B0c], args);
				break;
			case WHARD:
				reglcgen(&nod2, r, Z);
				r = &nod2;
				/* fall thru */
			case WADDR:
				biggen(l, r, Z, 0, binoptmp, args);
				if(ri == WHARD)
					regfree(r);
				break;
			}
			break;
		case IMM(1, 0):
			if(n->op == OSUB) {
				switch(li) {
				case WNONE:
					diag(l, "bad whatof\n");
					break;
				case WHARD:
					reglcgen(&nod2, l, Z);
					l = &nod2;
					/* fall thru */
				case WADDR:
				case WCONST:
					biggen(l, r, Z, 0, sub10, args);
					break;
				}
				if(li == WHARD)
					regfree(l);
			}
			else {
				switch(li) {
				case WNONE:
					diag(l, "bad whatof\n");
					break;
				case WCONST:
					biggen(r, l, Z, 0, optab[B0c], args);
					break;
				case WHARD:
					reglcgen(&nod2, l, Z);
					l = &nod2;
					/* fall thru */
				case WADDR:
					biggen(r, l, Z, 0, binoptmp, args);
					if(li == WHARD)
						regfree(l);
					break;
				}
			}
			break;
		case IMM(1, 1):
			switch(WW(li, ri)) {
			case WW(WCONST, WHARD):
				if(r->op == ONAME && n->op == OAND && reduxv(l))
					ri = WADDR;
				break;
			case WW(WHARD, WCONST):
				if(l->op == ONAME && n->op == OAND && reduxv(r))
					li = WADDR;
				break;
			}
			if(li == WHARD) {
				reglcgen(&nod3, l, Z);
				l = &nod3;
			}
			if(ri == WHARD) {
				reglcgen(&nod2, r, Z);
				r = &nod2;
			}
			d = regpair(nn, n);
			instpair(d, Z);
			switch(WW(li, ri)) {
			case WW(WCONST, WADDR):
			case WW(WCONST, WHARD):
				biggen(l, r, d, 0, optab[Bca], args);
				break;

			case WW(WADDR, WCONST):
			case WW(WHARD, WCONST):
				biggen(l, r, d, 0, optab[Bac], args);
				break;

			case WW(WADDR, WADDR):
			case WW(WADDR, WHARD):
			case WW(WHARD, WADDR):
			case WW(WHARD, WHARD):
				biggen(l, r, d, 0, binop11, args);
				break;

			default:
				diag(r, "bad whatof pair %d %d\n", li, ri);
				break;
			}
			if(li == WHARD)
				regfree(l);
			if(ri == WHARD)
				regfree(r);
			break;
		}

		nn->type = dt;

		if(d != Z)
			goto finished;

		switch(lri) {
		case IMM(0, 0):
			freepair(r);
			/* fall thru */;
		case IMM(0, 1):
			if(!dr)
				storepair(l, nn, 1);
			break;
		case IMM(1, 0):
			if(!dr)
				storepair(r, nn, 1);
			break;
		case IMM(1, 1):
			break;
		}
		return 1;

	shift:
		c = Z;

		/* evaluate hard subexps, stealing nn if possible. */
		/* must also secure CX.  not as many optims as binop. */
		switch(lri) {
		case IMM(0, 0):
		imm00:
			if(l->complex + 1 > r->complex) {
				if(dr)
					t = nn;
				else
					t = regpair(Z, l);
				sugen(l, t, 8);
				l = t;
				t = &nod1;
				c = snarfreg(l, t, D_CX, r, &nod2);
				cgen(r, t);
				r = t;
			}
			else {
				t = &nod1;
				c = snarfreg(nn, t, D_CX, r, &nod2);
				cgen(r, t);
				r = t;
				if(dr)
					t = nn;
				else
					t = regpair(Z, l);
				sugen(l, t, 8);
				l = t;
			}
			break;
		case IMM(0, 1):
		imm01:
			if(ri != WCONST) {
				lri = IMM(0, 0);
				goto imm00;
			}
			if(dr)
				t = nn;
			else
				t = regpair(Z, n);
			sugen(l, t, 8);
			l = t;
			break;
		case IMM(1, 0):
		imm10:
			if(li != WCONST) {
				lri = IMM(0, 0);
				goto imm00;
			}
			t = &nod1;
			c = snarfreg(nn, t, D_CX, r, &nod2);
			cgen(r, t);
			r = t;
			break;
		case IMM(1, 1):
			if(ri != WCONST) {
				lri = IMM(1, 0);
				goto imm10;
			}
			if(li == WHARD) {
				lri = IMM(0, 1);
				goto imm01;
			}
			break;
		}

		d = Z;

		switch(lri) {
		case IMM(0, 0):
			biggen(l, r, Z, 0, optab[S00], args);
			break;
		case IMM(0, 1):
			switch(ri) {
			case WNONE:
			case WADDR:
			case WHARD:
				diag(r, "bad whatof\n");
				break;
			case WCONST:
				m = r->vconst & 63;
				s = nodconst(m);
				if(m < 32)
					cp = optab[Sc0];
				else if(m == 32)
					cp = optab[Sc1];
				else
					cp = optab[Sc2];
				biggen(l, s, Z, 0, cp, args);
				break;
			}
			break;
		case IMM(1, 0):
			/* left is const */
			d = regpair(nn, n);
			instpair(d, Z);
			biggen(l, r, d, 0, optab[S10], args);
			regfree(r);
			break;
		case IMM(1, 1):
			d = regpair(nn, n);
			instpair(d, Z);
			switch(WW(li, ri)) {
			case WW(WADDR, WCONST):
				m = r->vconst & 63;
				s = nodconst(m);
				if(m < 32) {
					loadpair(l, d);
					l = d;
					cp = optab[Sc0];
				}
				else if(m == 32)
					cp = optab[Sac3];
				else
					cp = optab[Sac4];
				biggen(l, s, d, 0, cp, args);
				break;

			default:
				diag(r, "bad whatof pair %d %d\n", li, ri);
				break;
			}
			break;
		}

		if(c != Z) {
			gins(AMOVL, c, r);
			regfree(c);
		}

		if(d != Z)
			goto finished;

		switch(lri) {
		case IMM(0, 0):
			regfree(r);
			/* fall thru */
		case IMM(0, 1):
			if(!dr)
				storepair(l, nn, 1);
			break;
		case IMM(1, 0):
			regfree(r);
			break;
		case IMM(1, 1):
			break;
		}
		return 1;

	cmp:
		op = n->op;
		/* evaluate hard subexps */
		switch(lri) {
		case IMM(0, 0):
			if(l->complex > r->complex) {
				t = regpair(Z, l);
				sugen(l, t, 8);
				l = t;
				t = regpair(Z, r);
				sugen(r, t, 8);
				r = t;
			}
			else {
				t = regpair(Z, r);
				sugen(r, t, 8);
				r = t;
				t = regpair(Z, l);
				sugen(l, t, 8);
				l = t;
			}
			break;
		case IMM(1, 0):
			t = r;
			r = l;
			l = t;
			ri = li;
			op = invrel[relindex(op)];
			/* fall thru */
		case IMM(0, 1):
			t = regpair(Z, l);
			sugen(l, t, 8);
			l = t;
			break;
		case IMM(1, 1):
			break;
		}

		true = 1;
		optab = cmptab;
		switch(op) {
		case OEQ:
			optab = NEtab;
			true = 0;
			break;
		case ONE:
			optab = NEtab;
			break;
		case OLE:
			args = GTargs;
			true = 0;
			break;
		case OGT:
			args = GTargs;
			break;
		case OLS:
			args = HIargs;
			true = 0;
			break;
		case OHI:
			args = HIargs;
			break;
		case OLT:
			args = GEargs;
			true = 0;
			break;
		case OGE:
			args = GEargs;
			break;
		case OLO:
			args = HSargs;
			true = 0;
			break;
		case OHS:
			args = HSargs;
			break;
		default:
			diag(n, "bad cmp\n");
			SET(optab);
		}

		switch(lri) {
		case IMM(0, 0):
			biggen(l, r, Z, true, optab[T0i], args);
			break;
		case IMM(0, 1):
		case IMM(1, 0):
			switch(ri) {
			case WNONE:
				diag(l, "bad whatof\n");
				break;
			case WCONST:
				biggen(l, r, Z, true, optab[T0i], args);
				break;
			case WHARD:
				reglcgen(&nod2, r, Z);
				r = &nod2;
				/* fall thru */
			case WADDR:
				biggen(l, r, Z, true, optab[T0i], args);
				if(ri == WHARD)
					regfree(r);
				break;
			}
			break;
		case IMM(1, 1):
			if(li == WHARD) {
				reglcgen(&nod3, l, Z);
				l = &nod3;
			}
			if(ri == WHARD) {
				reglcgen(&nod2, r, Z);
				r = &nod2;
			}
			biggen(l, r, Z, true, optab[Tii], args);
			if(li == WHARD)
				regfree(l);
			if(ri == WHARD)
				regfree(r);
			break;
		}

		switch(lri) {
		case IMM(0, 0):
			freepair(r);
			/* fall thru */;
		case IMM(0, 1):
		case IMM(1, 0):
			freepair(l);
			break;
		case IMM(1, 1):
			break;
		}
		return 1;

	case OASMUL:
	case OASLMUL:
		m = 0;
		goto mulop;

	case OMUL:
	case OLMUL:
		m = 1;
		goto mulop;

	mulop:
		dr = nn != Z && nn->op == OREGPAIR;
		l = vfunc(n->left, nn);
		r = vfunc(n->right, nn);
		if(r->op != OCONST) {
			if(l->complex > r->complex) {
				if(m) {
					t = l;
					l = r;
					r = t;
				}
				else if(!vaddr(l, 1)) {
					reglcgen(&nod5, l, Z);
					l = &nod5;
					evacaxdx(l);
				}
			}
			t = regpair(Z, n);
			sugen(r, t, 8);
			r = t;
			evacaxdx(r->left);
			evacaxdx(r->right);
			if(l->complex <= r->complex && !m && !vaddr(l, 1)) {
				reglcgen(&nod5, l, Z);
				l = &nod5;
				evacaxdx(l);
			}
		}
		if(dr)
			t = nn;
		else
			t = regpair(Z, n);
		c = Z;
		d = Z;
		if(!nodreg(&nod1, t->left, D_AX)) {
			if(t->left->reg != D_AX){
				t->left->reg = D_AX;
				reg[D_AX]++;
			}else if(reg[D_AX] == 0)
				fatal(Z, "vlong mul AX botch");
		}
		if(!nodreg(&nod2, t->right, D_DX)) {
			if(t->right->reg != D_DX){
				t->right->reg = D_DX;
				reg[D_DX]++;
			}else if(reg[D_DX] == 0)
				fatal(Z, "vlong mul DX botch");
		}
		if(m)
			sugen(l, t, 8);
		else
			loadpair(l, t);
		if(t->left->reg != D_AX) {
			c = &nod3;
			regsalloc(c, t->left);
			gmove(&nod1, c);
			gmove(t->left, &nod1);
			zapreg(t->left);
		}
		if(t->right->reg != D_DX) {
			d = &nod4;
			regsalloc(d, t->right);
			gmove(&nod2, d);
			gmove(t->right, &nod2);
			zapreg(t->right);
		}
		if(c != Z || d != Z) {
			s = regpair(Z, n);
			s->left = &nod1;
			s->right = &nod2;
		}
		else
			s = t;
		if(r->op == OCONST) {
			if(hi64v(r) == 0)
				biggen(s, r, Z, 0, mulc32, nil);
			else
				biggen(s, r, Z, 0, mulc64, nil);
		}
		else
			biggen(s, r, Z, 0, mull, nil);
		instpair(t, Z);
		if(c != Z) {
			gmove(&nod1, t->left);
			gmove(&nod3, &nod1);
		}
		if(d != Z) {
			gmove(&nod2, t->right);
			gmove(&nod4, &nod2);
		}
		if(r->op == OREGPAIR)
			freepair(r);
		if(!m)
			storepair(t, l, 0);
		if(l == &nod5)
			regfree(l);
		if(!dr) {
			if(nn != Z)
				storepair(t, nn, 1);
			else
				freepair(t);
		}
		return 1;

	case OASADD:
		args = ADDargs;
		goto vasop;
	case OASAND:
		args = ANDargs;
		goto vasop;
	case OASOR:
		args = ORargs;
		goto vasop;
	case OASSUB:
		args = SUBargs;
		goto vasop;
	case OASXOR:
		args = XORargs;
		goto vasop;

	vasop:
		l = n->left;
		r = n->right;
		dr = nn != Z && nn->op == OREGPAIR;
		m = 0;
		if(l->complex > r->complex) {
			if(!vaddr(l, 1)) {
				reglcgen(&nod1, l, Z);
				l = &nod1;
			}
			if(!vaddr(r, 1) || nn != Z || r->op == OCONST) {
				if(dr)
					t = nn;
				else
					t = regpair(Z, r);
				sugen(r, t, 8);
				r = t;
				m = 1;
			}
		}
		else {
			if(!vaddr(r, 1) || nn != Z || r->op == OCONST) {
				if(dr)
					t = nn;
				else
					t = regpair(Z, r);
				sugen(r, t, 8);
				r = t;
				m = 1;
			}
			if(!vaddr(l, 1)) {
				reglcgen(&nod1, l, Z);
				l = &nod1;
			}
		}
		if(nn != Z) {
			if(n->op == OASSUB)
				biggen(l, r, Z, 0, sub10, args);
			else
				biggen(r, l, Z, 0, binoptmp, args);
			storepair(r, l, 0);
		}
		else {
			if(m)
				biggen(l, r, Z, 0, binop00, args);
			else
				biggen(l, r, Z, 0, binoptmp, args);
		}
		if(l == &nod1)
			regfree(&nod1);
		if(m) {
			if(nn == Z)
				freepair(r);
			else if(!dr)
				storepair(r, nn, 1);
		}
		return 1;

	case OASASHL:
		args = nil;
		optab = asshlltab;
		goto assh;
	case OASLSHR:
		args = shrlargs;
		optab = asshrltab;
		goto assh;
	case OASASHR:
		args = sarlargs;
		optab = asshrltab;
		goto assh;

	assh:
		c = Z;
		l = n->left;
		r = n->right;
		if(r->op == OCONST) {
			m = r->vconst & 63;
			if(m < 32)
				m = SAclo;
			else if(m == 32)
				m = SAc32;
			else
				m = SAchi;
		}
		else
			m = SAgen;
		if(l->complex > r->complex) {
			if(!vaddr(l, 0)) {
				reglcgen(&nod1, l, Z);
				l = &nod1;
			}
			if(m == SAgen) {
				t = &nod2;
				if(l->reg == D_CX) {
					regalloc(t, r, Z);
					gmove(l, t);
					l->reg = t->reg;
					t->reg = D_CX;
				}
				else
					c = snarfreg(nn, t, D_CX, r, &nod3);
				cgen(r, t);
				r = t;
			}
		}
		else {
			if(m == SAgen) {
				t = &nod2;
				c = snarfreg(nn, t, D_CX, r, &nod3);
				cgen(r, t);
				r = t;
			}
			if(!vaddr(l, 0)) {
				reglcgen(&nod1, l, Z);
				l = &nod1;
			}
		}

		if(nn != Z) {
			m += SAdgen - SAgen;
			d = regpair(nn, n);
			instpair(d, Z);
			biggen(l, r, d, 0, optab[m], args);
			if(l == &nod1) {
				regfree(&nod1);
				l = Z;
			}
			if(r == &nod2 && c == Z) {
				regfree(&nod2);
				r = Z;
			}
			if(d != nn)
				storepair(d, nn, 1);
		}
		else
			biggen(l, r, Z, 0, optab[m], args);

		if(c != Z) {
			gins(AMOVL, c, r);
			regfree(c);
		}
		if(l == &nod1)
			regfree(&nod1);
		if(r == &nod2)
			regfree(&nod2);
		return 1;

	case OPOSTINC:
		args = ADDargs;
		cp = incdecpost;
		goto vinc;
	case OPOSTDEC:
		args = SUBargs;
		cp = incdecpost;
		goto vinc;
	case OPREINC:
		args = ADDargs;
		cp = incdecpre;
		goto vinc;
	case OPREDEC:
		args = SUBargs;
		cp = incdecpre;
		goto vinc;

	vinc:
		l = n->left;
		if(!vaddr(l, 1)) {
			reglcgen(&nod1, l, Z);
			l = &nod1;
		}
		
		if(nn != Z) {
			d = regpair(nn, n);
			instpair(d, Z);
			biggen(l, Z, d, 0, cp, args);
			if(l == &nod1) {
				regfree(&nod1);
				l = Z;
			}
			if(d != nn)
				storepair(d, nn, 1);
		}
		else
			biggen(l, Z, Z, 0, incdec, args);

		if(l == &nod1)
			regfree(&nod1);
		return 1;

	case OCAST:
		l = n->left;
		if(typev[l->type->etype]) {
			if(!vaddr(l, 1)) {
				if(l->complex + 1 > nn->complex) {
					d = regpair(Z, l);
					sugen(l, d, 8);
					if(!vaddr(nn, 1)) {
						reglcgen(&nod1, nn, Z);
						r = &nod1;
					}
					else
						r = nn;
				}
				else {
					if(!vaddr(nn, 1)) {
						reglcgen(&nod1, nn, Z);
						r = &nod1;
					}
					else
						r = nn;
					d = regpair(Z, l);
					sugen(l, d, 8);
				}
//				d->left->type = r->type;
				d->left->type = types[TLONG];
				gmove(d->left, r);
				freepair(d);
			}
			else {
				if(nn->op != OREGISTER && !vaddr(nn, 1)) {
					reglcgen(&nod1, nn, Z);
					r = &nod1;
				}
				else
					r = nn;
//				l->type = r->type;
				l->type = types[TLONG];
				gmove(l, r);
			}
			if(r != nn)
				regfree(r);
		}
		else {
			if(typeu[l->type->etype] || cond(l->op))
				si = TUNSIGNED;
			else
				si = TSIGNED;
			regalloc(&nod1, l, Z);
			cgen(l, &nod1);
			if(nn->op == OREGPAIR) {
				m = instpair(nn, &nod1);
				biggen(&nod1, Z, nn, si == TSIGNED, castrp, nil);
			}
			else {
				m = 0;
				if(!vaddr(nn, si != TSIGNED)) {
					dt = nn->type;
					nn->type = types[TLONG];
					reglcgen(&nod2, nn, Z);
					nn->type = dt;
					nn = &nod2;
				}
				dt = nn->type;
				nn->type = types[TLONG];
				biggen(&nod1, Z, nn, si == TSIGNED, castrpa, nil);
				nn->type = dt;
				if(nn == &nod2)
					regfree(&nod2);
			}
			if(!m)
				regfree(&nod1);
		}
		return 1;

	default:
		if(n->op == OREGPAIR) {
			storepair(n, nn, 1);
			return 1;
		}
		if(nn->op == OREGPAIR) {
			loadpair(n, nn);
			return 1;
		}
		return 0;
	}
finished:
	if(d != nn)
		storepair(d, nn, 1);
	return 1;
}

void
testv(Node *n, int true)
{
	Type *t;
	Node *nn, nod, *b;

	if(machcap(Z)) {
		b = &nod;
		b->op = true ? ONE : OEQ;
		b->left = n;
		b->right = new(0, Z, Z);
		*b->right = *nodconst(0);
		b->right->type = n->type;
		b->type = types[TLONG];
		cgen64(b, Z);
		return;
	}

	switch(n->op) {
	case OINDREG:
	case ONAME:
		biggen(n, Z, Z, true, testi, nil);
		break;

	default:
		n = vfunc(n, n);
		if(n->addable >= INDEXED) {
			t = n->type;
			n->type = types[TLONG];
			reglcgen(&nod, n, Z);
			n->type = t;
			n = &nod;
			biggen(n, Z, Z, true, testi, nil);
			if(n == &nod)
				regfree(n);
		}
		else {
			nn = regpair(Z, n);
			sugen(n, nn, 8);
			biggen(nn, Z, Z, true, testi, nil);
			freepair(nn);
		}
	}
}