From 8ac67646a2025f1ae431f8827a8a586497c993dd Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@gmx.de>
Date: Tue, 18 Jun 2013 21:49:19 +0200
Subject: [PATCH] libaml: pikeshedd style, handle division by zero (thanks
 erik)

---
 sys/src/libaml/aml.c | 415 ++++++++++++++++++++++++-------------------
 1 file changed, 234 insertions(+), 181 deletions(-)

diff --git a/sys/src/libaml/aml.c b/sys/src/libaml/aml.c
index 22201b4bd..2860c4180 100644
--- a/sys/src/libaml/aml.c
+++ b/sys/src/libaml/aml.c
@@ -47,7 +47,8 @@ static char *spacename[] = {
 	"Smbus",
 	"Cmos",
 	"Pcibar",
-	"Ipmi" };
+	"Ipmi",
+};
 
 /* field flags */
 enum {
@@ -175,15 +176,22 @@ static uchar octab1[];
 static uchar octab2[];
 
 static Name*
-rootname(Name *dot){
+rootname(Name *dot)
+{
 	while(dot != dot->up)
 		dot = dot->up;
 	return dot;
 }
 
 static void
-gcmark(void *p){
+gcmark(void *p)
+{
+	int i;
+	Env *e;
+	Field *f;
 	Heap *h;
+	Name *n, *d;
+	Package *a;
 
 	if(p == nil)
 		return;
@@ -193,35 +201,29 @@ gcmark(void *p){
 	h->mark = 1;
 	switch(h->tag){
 	case 'E':
-		{
-			int i;
-			Env *e = p;
-			for(i=0; i<nelem(e->loc); i++)
-				gcmark(e->loc[i]);
-			for(i=0; i<nelem(e->arg); i++)
-				gcmark(e->arg[i]);
-		}
+		e = p;
+		for(i=0; i<nelem(e->loc); i++)
+			gcmark(e->loc[i]);
+		for(i=0; i<nelem(e->arg); i++)
+			gcmark(e->arg[i]);
 		break;
-	case 'R': case 'A': case 'L':
+	case 'R':
+	case 'A':
+	case 'L':
 		gcmark(((Ref*)p)->ref);
 		break;
 	case 'N':
-		{
-			Name *d, *n = p;
-			gcmark(n->v);
-			for(d = n->down; d; d = d->next)
-				gcmark(d);
-			gcmark(n->fork);
-			gcmark(n->up);
-		}
+		n = p;
+		gcmark(n->v);
+		for(d = n->down; d; d = d->next)
+			gcmark(d);
+		gcmark(n->fork);
+		gcmark(n->up);
 		break;
 	case 'p':
-		{
-			int i;
-			Package *a = p;
-			for(i=0; i<a->n; i++)
-				gcmark(a->a[i]);
-		}
+		a = p;
+		for(i=0; i<a->n; i++)
+			gcmark(a->a[i]);
 		break;
 	case 'r':
 		gcmark(((Region*)p)->name);
@@ -231,21 +233,20 @@ gcmark(void *p){
 		break;
 	case 'f':
 	case 'u':
-		{
-			Field *f = p;
-			gcmark(f->reg);
-			gcmark(f->index);
-			gcmark(f->indexv);
-		}
+		f = p;
+		gcmark(f->reg);
+		gcmark(f->index);
+		gcmark(f->indexv);
 		break;
 	}
 }
 
 static int
-gc(void){
+gc(void)
+{
+	int i;
 	Heap *h, **hh;
 	Frame *f;
-	int i;
 
 	for(h = hp; h; h = h->link)
 		h->mark = 0;
@@ -277,7 +278,8 @@ gc(void){
 }
 
 static void*
-mk(int tag, int size){
+mk(int tag, int size)
+{
 	Heap *h;
 	int a;
 
@@ -291,21 +293,26 @@ mk(int tag, int size){
 }
 
 static uvlong*
-mki(uvlong i){
-	uvlong *v = mk('i', sizeof(uvlong));
+mki(uvlong i)
+{
+	uvlong *v;
+
+	v = mk('i', sizeof(uvlong));
 	*v = i;
 	return v;
 }
 
 static char*
-mks(char *s){
+mks(char *s)
+{
 	char *r = mk('s', strlen(s)+1);
 	strcpy(r, s);
 	return r;
 }
 
 static int
-pkglen(uchar *p, uchar *e, uchar **np){
+pkglen(uchar *p, uchar *e, uchar **np)
+{
 	ulong n;
 	uchar b;
 
@@ -336,7 +343,8 @@ pkglen(uchar *p, uchar *e, uchar **np){
 }
 
 static Name*
-forkname(Name *dot){
+forkname(Name *dot)
+{
 	Name *n;
 
 	n = mk('N', sizeof(Name));
@@ -355,7 +363,8 @@ forkname(Name *dot){
 }
 
 static Name*
-getseg(Name *dot, void *seg, int new){
+getseg(Name *dot, void *seg, int new)
+{
 	Name *n, *l;
 
 	for(n = l = nil; dot; dot = dot->fork){
@@ -425,12 +434,15 @@ getname(Name *dot, char *path, int new)
 }
 
 static uvlong
-ival(void *p){
-	if(p) switch(TAG(p)){
-	case 'i':
-		return *((uvlong*)p);
-	case 's':
-		return strtoull((char*)p, 0, 0);
+ival(void *p)
+{
+	if(p != nil){
+		switch(TAG(p)){
+		case 'i':
+			return *((uvlong*)p);
+		case 's':
+			return strtoull((char*)p, 0, 0);
+		}
 	}
 	return 0;
 }
@@ -495,7 +507,8 @@ fieldalign(int flags)
 }
 
 static void*
-rwfield(Field *f, void *v, int write){
+rwfield(Field *f, void *v, int write)
+{
 	int boff, blen, wo, ws, wl, wa, wd, i;
 	uvlong w, m;
 	void *reg;
@@ -552,6 +565,7 @@ rwfield(Field *f, void *v, int write){
 		return nil;
 	if(blen > 64)
 		return b;
+
 	w = 0;
 	for(i=0; i<SIZE(b); i++)
 		w |= ((uvlong)b[i]) << i*8;
@@ -559,7 +573,8 @@ rwfield(Field *f, void *v, int write){
 }
 
 static void*
-deref(void *p){
+deref(void *p)
+{
 	if(p) switch(TAG(p)){
 	case 'N':
 		return ((Name*)p)->v;
@@ -572,9 +587,11 @@ deref(void *p){
 }
 
 static void*
-copy(int tag, void *s){
+copy(int tag, void *s)
+{
 	void *d;
-	if(s){
+
+	if(s != nil){
 		int n;
 		if(tag == 0)
 			tag = TAG(s);
@@ -597,7 +614,8 @@ copy(int tag, void *s){
 }
 
 static void*
-store(void *s, void *d){
+store(void *s, void *d)
+{
 	void *p, **pp;
 
 	if(d == nil)
@@ -641,10 +659,11 @@ store(void *s, void *d){
 }
 
 static int
-Nfmt(Fmt *f){
+Nfmt(Fmt *f)
+{
 	char buf[5];
-	Name *n;
 	int i;
+	Name *n;
 
 	n = va_arg(f->args, Name*);
 	if(n == nil)
@@ -664,9 +683,17 @@ Nfmt(Fmt *f){
 }
 
 static int
-Vfmt(Fmt *f){
+Vfmt(Fmt *f)
+{
 	void *p;
-	int c;
+	int i, n, c;
+	Env *e;
+	Field *l;
+	Name *nm;
+	Method *m;
+	Package *a;
+	Region *g;
+	Ref *r;
 
 	p = va_arg(f->args, void*);
 	if(p == nil)
@@ -674,90 +701,74 @@ Vfmt(Fmt *f){
 	c = TAG(p);
 	switch(c){
 	case 'N':
-		{
-			Name *n = p;
-
-			if(n->v != n)
-				return fmtprint(f, "%N=%V", n, n->v);
-			return fmtprint(f, "%N=*", n);
-		}
-	case 'A': case 'L':
-		{
-			Ref *r = p;
-			Env *e = r->ref;
-			if(c == 'A')
-				return fmtprint(f, "Arg%ld=%V", r->ptr - e->arg, *r->ptr);
-			if(c == 'L')
-				return fmtprint(f, "Local%ld=%V", r->ptr - e->loc, *r->ptr);
-		}
+		nm = p;
+		if(nm->v != nm)
+			return fmtprint(f, "%N=%V", nm, nm->v);
+		return fmtprint(f, "%N=*", nm);
+	case 'A':
+	case 'L':
+		r = p;
+		e = r->ref;
+		if(c == 'A')
+			return fmtprint(f, "Arg%ld=%V", r->ptr - e->arg, *r->ptr);
+		if(c == 'L')
+			return fmtprint(f, "Local%ld=%V", r->ptr - e->loc, *r->ptr);
 	case 's':
 		return fmtprint(f, "\"%s\"", (char*)p);
 	case 'i':
-		return fmtprint(f, "0x%llux", *((uvlong*)p));
+		return fmtprint(f, "%#llux", *((uvlong*)p));
 	case 'p':
-		{
-			int i;
-			Package *a = p;
-			fmtprint(f, "Package(%d){", a->n);
-			for(i=0; i<a->n; i++){
-				if(i > 0)
-					fmtprint(f, ", ");
-				fmtprint(f, "%V", a->a[i]);
-			}
-			fmtprint(f, "}");
+		a = p;
+		fmtprint(f, "Package(%d){", a->n);
+		for(i=0; i<a->n; i++){
+			if(i > 0)
+				fmtprint(f, ", ");
+			fmtprint(f, "%V", a->a[i]);
 		}
+		fmtprint(f, "}");
 		return 0;
 	case 'b':
-		{
-			int i, n;
-			n = SIZE(p);
-			fmtprint(f, "Buffer(%d){", n);
-			for(i=0; i<n; i++){
-				if(i > 0)
-					fmtprint(f, ", ");
-				fmtprint(f, "%.2uX", ((uchar*)p)[i]);
-			}
-			fmtprint(f, "}");
+		n = SIZE(p);
+		fmtprint(f, "Buffer(%d){", n);
+		for(i=0; i<n; i++){
+			if(i > 0)
+				fmtprint(f, ", ");
+			fmtprint(f, "%.2uX", ((uchar*)p)[i]);
 		}
+		fmtprint(f, "}");
 		return 0;
 	case 'r':
-		{
-			Region *r = p;
-			return fmtprint(f, "Region(%s, 0x%llux, 0x%llux)",
-				spacename[r->space & 7], r->off, r->len);
-		}
+		g = p;
+		return fmtprint(f, "Region(%s, %#llux, %#llux)",
+			spacename[g->space & 7], g->off, g->len);
 	case 'm':
-		{
-			int i;
-			Method *m = p;
-			fmtprint(f, "%N(", m->name);
-			for(i=0; i < m->narg; i++){
-				if(i > 0)
-					fmtprint(f, ", ");
-				fmtprint(f, "Arg%d", i);
-			}
-			fmtprint(f, ")");
-			return 0;
+		m = p;
+		fmtprint(f, "%N(", m->name);
+		for(i=0; i < m->narg; i++){
+			if(i > 0)
+				fmtprint(f, ", ");
+			fmtprint(f, "Arg%d", i);
 		}
+		fmtprint(f, ")");
+		return 0;
 	case 'u':
 		fmtprint(f, "Buffer");
 		/* no break */
 	case 'f':
-		{
-			Field *l = p;
-			if(l->index)
-				return fmtprint(f, "IndexField(%x, %x, %x) @ %V[%V]",
-					l->flags, l->bitoff, l->bitlen, l->index, l->indexv);
-			return fmtprint(f, "Field(%x, %x, %x) @ %V",
-				l->flags, l->bitoff, l->bitlen, l->reg);
-		}
+		l = p;
+		if(l->index)
+			return fmtprint(f, "IndexField(%x, %x, %x) @ %V[%V]",
+				l->flags, l->bitoff, l->bitlen, l->index, l->indexv);
+		return fmtprint(f, "Field(%x, %x, %x) @ %V",
+			l->flags, l->bitoff, l->bitlen, l->reg);
 	default:
 		return fmtprint(f, "%c:%p", c, p);
 	}
 }
 
 static void
-dumpregs(void){
+dumpregs(void)
+{
 	Frame *f;
 	Env *e;
 	int i;
@@ -789,7 +800,8 @@ dumpregs(void){
 }
 
 static int
-xec(uchar *pc, uchar *end, Name *dot, Env *env, void **pret){
+xec(uchar *pc, uchar *end, Name *dot, Env *env, void **pret)
+{
 	static int loop;
 	int i, c;
 	void *r;
@@ -820,12 +832,12 @@ xec(uchar *pc, uchar *end, Name *dot, Env *env, void **pret){
 		default:
 			if(PC >= FP->end){
 			Overrun:
-				print("PC overrun frame end");
+				print("aml: PC overrun frame end");
 				goto Out;
 			}
 			FP++;
 			if(FP >= FT){
-				print("frame stack overflow");
+				print("aml: frame stack overflow");
 				goto Out;
 			}
 			*FP = FP[-1];
@@ -870,7 +882,10 @@ xec(uchar *pc, uchar *end, Name *dot, Env *env, void **pret){
 			((uchar*)r)[c] = 0;
 			PC = end;
 			break;
-		case '1': case '2': case '4': case '8':
+		case '1':
+		case '2':
+		case '4':
+		case '8':
 			end = PC+(c-'0');
 			if(end > FP->end)
 				goto Overrun;
@@ -950,7 +965,8 @@ Out:
 }
 
 static void*
-evalnamec(void){
+evalnamec(void)
+{
 	int s, c, new;
 	Name *x, *dot;
 
@@ -998,12 +1014,14 @@ evalnamec(void){
 }
 
 static void*
-evaliarg0(){
+evaliarg0(void)
+{
 	return FP->arg[0];
 }
 
 static void*
-evalconst(void){
+evalconst(void)
+{
 	switch(FP->start[0]){
 	case 0x01:
 		return mki(1);
@@ -1014,7 +1032,8 @@ evalconst(void){
 }
 
 static void*
-evalbuf(void){
+evalbuf(void)
+{
 	int n, m;
 	uchar *p;
 
@@ -1029,12 +1048,13 @@ evalbuf(void){
 }
 
 static void*
-evalpkg(void){
+evalpkg(void)
+{
 	Package *p;
 	void **x;
 	int n;
 
-	if(p = FP->ref){
+	if((p = FP->ref) != nil){
 		x = FP->aux;
 		if(x >= &p->a[0] && x < &p->a[p->n]){
 			*x++ = FP->arg[0];
@@ -1052,7 +1072,8 @@ evalpkg(void){
 }
 
 static void*
-evalname(void){
+evalname(void)
+{
 	Name *n;
 
 	if(n = FP->arg[0])
@@ -1063,7 +1084,8 @@ evalname(void){
 }
 
 static void*
-evalscope(void){
+evalscope(void)
+{
 	Name *n;
 
 	if(n = FP->arg[0])
@@ -1075,7 +1097,8 @@ evalscope(void){
 }
 
 static void*
-evalalias(void){
+evalalias(void)
+{
 	Name *n;
 
 	if(n = FP->arg[1])
@@ -1084,10 +1107,12 @@ evalalias(void){
 }
 
 static void*
-evalmet(void){
+evalmet(void)
+{
 	Name *n;
+	Method *m;
+
 	if(n = FP->arg[0]){
-		Method *m;
 		m = mk('m', sizeof(Method));
 		m->narg = ival(FP->arg[1]) & 7;
 		m->start = PC;
@@ -1100,10 +1125,12 @@ evalmet(void){
 }
 
 static void*
-evalreg(void){
+evalreg(void)
+{
 	Name *n;
+	Region *r;
+
 	if(n = FP->arg[0]){
-		Region *r;
 		r = mk('r', sizeof(Region));
 		r->space = ival(FP->arg[1]);
 		r->off = ival(FP->arg[2]);
@@ -1115,7 +1142,8 @@ evalreg(void){
 }
 
 static void*
-evalcfield(void){
+evalcfield(void)
+{
 	void *r;
 	Field *f;
 	Name *n;
@@ -1158,7 +1186,8 @@ evalcfield(void){
 }
 
 static void*
-evalfield(void){
+evalfield(void)
+{
 	int flags, bitoff, wa, n;
 	Field *f, *df;
 	Name *d;
@@ -1226,15 +1255,17 @@ Out:
 }
 
 static void*
-evalnop(void){
+evalnop(void)
+{
 	return nil;
 }
 
 static void*
-evalbad(void){
+evalbad(void)
+{
 	int i;
 
-	print("bad opcode %p: ", PC);
+	print("aml: bad opcode %p: ", PC);
 	for(i=0; i < 8 && (FP->start+i) < FP->end; i++){
 		if(i > 0)
 			print(" ");
@@ -1248,7 +1279,8 @@ evalbad(void){
 }
 
 static void*
-evalcond(void){
+evalcond(void)
+{
 	switch(FP->op - optab){
 	case Oif:
 		if(FP <= FB)
@@ -1283,7 +1315,8 @@ evalcond(void){
 }
 
 static void*
-evalcmp(void){
+evalcmp(void)
+{
 	void *a, *b;
 	int c;
 
@@ -1327,7 +1360,8 @@ evalcmp(void){
 }
 
 static void*
-evalcall(void){
+evalcall(void)
+{
 	Method *m;
 	Env *e;
 	int i;
@@ -1360,7 +1394,8 @@ evalcall(void){
 }
 
 static void*
-evalret(void){
+evalret(void)
+{
 	void *r = FP->arg[0];
 	int brk = (FP->op - optab) != Oret;
 	while(--FP >= FB){
@@ -1381,7 +1416,8 @@ evalret(void){
 }
 
 static void*
-evalenv(void){
+evalenv(void)
+{
 	Ref *r;
 	Env *e;
 	int c;
@@ -1402,12 +1438,14 @@ evalenv(void){
 }
 
 static void*
-evalstore(void){
+evalstore(void)
+{
 	return store(FP->arg[0], FP->arg[1]);
 }
 
 static void*
-evalindex(void){
+evalindex(void)
+{
 	Field *f;
 	void *p;
 	Ref *r;
@@ -1441,7 +1479,8 @@ evalindex(void){
 }
 
 static void*
-evalcondref(void){
+evalcondref(void)
+{
 	void *s;
 	if((s = FP->arg[0]) == nil)
 		return nil;
@@ -1450,12 +1489,14 @@ evalcondref(void){
 }
 
 static void*
-evalsize(void){
+evalsize(void)
+{
 	return mki(amllen(FP->arg[0]));
 }
 
 static void*
-evalderef(void){
+evalderef(void)
+{
 	void *p;
 
 	if(p = FP->arg[0]){
@@ -1467,8 +1508,12 @@ evalderef(void){
 }
 
 static void*
-evalarith(void){
-	void *r = nil;
+evalarith(void)
+{
+	uvlong v, d;
+	void *r;
+
+	r = nil;
 	switch(FP->op - optab){
 	case Oadd:
 		r = mki(ival(FP->arg[0]) + ival(FP->arg[1]));
@@ -1476,27 +1521,24 @@ evalarith(void){
 	case Osub:
 		r = mki(ival(FP->arg[0]) - ival(FP->arg[1]));
 		break;
-	case Omod:
-		{
-			uvlong d;
-			d = ival(FP->arg[1]);
-			r = mki(ival(FP->arg[0]) % d);
-		}
-		break;
 	case Omul:
 		r = mki(ival(FP->arg[0]) * ival(FP->arg[1]));
 		break;
+	case Omod:
 	case Odiv:
-		{
-			uvlong v, d;
-			v = ival(FP->arg[0]);
-			d = ival(FP->arg[1]);
-			r = mki(v / d);
-			if(FP->arg[2])
-				store(mki(v % d), FP->arg[2]);
-			store(r, FP->arg[3]); 
-			return r;
+		v = ival(FP->arg[0]);
+		d = ival(FP->arg[1]);
+		if(d == 0){
+			print("aml: division by zero: PC=%#p\n", PC);
+			return nil;
 		}
+		r = mki(v % d);
+		store(r, FP->arg[2]);
+		if((FP->op - optab) != Odiv)
+			return r;
+		r = mki(v / d);
+		store(r, FP->arg[3]); 
+		return r;
 	case Oshl:
 		r = mki(ival(FP->arg[0]) << ival(FP->arg[1]));
 		break;
@@ -1701,12 +1743,14 @@ static uchar octab2[] = {
 };
 
 int
-amltag(void *p){
+amltag(void *p)
+{
 	return p ? TAG(p) : 0;
 }
 
 void*
-amlval(void *p){
+amlval(void *p)
+{
 	p = deref(p);
 	if(p && TAG(p) == 'p')
 		p = ((Package*)p)->a;
@@ -1714,12 +1758,14 @@ amlval(void *p){
 }
 
 uvlong
-amlint(void *p){
+amlint(void *p)
+{
 	return ival(p);
 }
 
 int
-amllen(void *p){
+amllen(void *p)
+{
 	while(p){
 		switch(TAG(p)){
 		case 'R':
@@ -1737,7 +1783,8 @@ amllen(void *p){
 }
 
 void
-amlinit(void){
+amlinit(void)
+{
 	Name *n;
 
 	fmtinstall('V', Vfmt);
@@ -1771,24 +1818,28 @@ amlinit(void){
 }
 
 void
-amlexit(void){
+amlexit(void)
+{
 	amlroot = nil;
 	FP = FB-1;
 	gc();
 }
 
 int
-amlload(uchar *data, int len){
+amlload(uchar *data, int len)
+{
 	return xec(data, data+len, amlroot, nil, nil);
 }
 
 void*
-amlwalk(void *dot, char *name){
+amlwalk(void *dot, char *name)
+{
 	return getname(dot, name, 0);
 }
 
 void
-amlenum(void *dot, char *seg, int (*proc)(void *, void *), void *arg){
+amlenum(void *dot, char *seg, int (*proc)(void *, void *), void *arg)
+{
 	Name *n, *d;
 	int rec;
 
@@ -1806,7 +1857,8 @@ amlenum(void *dot, char *seg, int (*proc)(void *, void *), void *arg){
 }
 
 int
-amleval(void *dot, char *fmt, ...){
+amleval(void *dot, char *fmt, ...)
+{
 	va_list a;
 	Method *m;
 	void **r;
@@ -1830,13 +1882,14 @@ amleval(void *dot, char *fmt, ...){
 	}
 	r = va_arg(a, void**);
 	va_end(a);
-	if(dot = deref(dot)) switch(TAG(dot)){
-	case 'm':
+	if(dot = deref(dot))
+	if(TAG(dot) == 'm'){
 		m = dot;
 		if(i != m->narg)
 			return -1;
 		return xec(m->start, m->end, forkname(m->name), e, r);
 	}
-	if(r) *r = dot;
+	if(r != nil)
+		*r = dot;
 	return 0;
 }