From 82a008e85162e5080b3b87ee59fa829c7d1bd375 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 30 Nov 1992 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1992-11-30

---
 power/dat.h  |  4 ----
 power/mmu.c  | 16 ++++++----------
 power/trap.c | 20 ++++++++------------
 3 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/power/dat.h b/power/dat.h
index 21518b8ecc63509c1ed551629cd40fa466c23049..36eec58d9a7fec588ccb388cef63be0b2cbf9592 100644
--- a/power/dat.h
+++ b/power/dat.h
@@ -109,10 +109,6 @@ struct Mach
 	int	load;
 	int	intr;
 	int	ledval;			/* value last written to LED */
-ulong cause;
-ulong status;
-ulong ur;
-ulong sp;
 
 	int	stack[1];
 };
diff --git a/power/mmu.c b/power/mmu.c
index aef0f7bfaf46d2f528751bde5716e835ce743077..39635632545fdd4d852f7cb51ec6885982764d43 100644
--- a/power/mmu.c
+++ b/power/mmu.c
@@ -14,7 +14,6 @@ mapstack(Proc *p)
 	ulong tlbvirt, tlbphys;
 
 	if(p->newtlb) {
-		/* see flushmmu. */
 		memset(p->pidonmach, 0, sizeof p->pidonmach);
 		p->newtlb = 0;
 	}
@@ -22,12 +21,9 @@ mapstack(Proc *p)
 	tp = p->pidonmach[m->machno];
 	if(tp == 0)
 		tp = newtlbpid(p);
-/*	if(p->upage->va != (USERADDR|(p->pid&0xFFFF)) && p->pid != 0)
-		panic("mapstack %d 0x%lux 0x%lux", p->pid, p->upage->pa, p->upage->va);
-*/
-	/* don't set m->pidhere[tp] because we're only writing entry 0 */
+
 	tlbvirt = USERADDR | PTEPID(tp);
-	tlbphys = p->upage->pa | PTEWRITE | PTEVALID | PTEGLOBL;
+	tlbphys = p->upage->pa | PTEWRITE|PTEVALID|PTEGLOBL;
 	puttlbx(0, tlbvirt, tlbphys);
 	u = (User*)USERADDR;
 }
@@ -66,6 +62,7 @@ newtlbpid(Proc *p)
 	}
 	if(h[i])
 		purgetlb(i);
+
 	sp = m->pidproc[i];
 	if(sp && sp->pidonmach[m->machno] == i)
 		sp->pidonmach[m->machno] = 0;
@@ -92,12 +89,10 @@ putmmu(ulong tlbvirt, ulong tlbphys, Page *pg)
 	}
 
 	p = u->p;
-/*	if(p->state != Running)
-		panic("putmmu state %lux %lux %s\n", u, p, statename[p->state]);
-*/
 	tp = p->pidonmach[m->machno];
 	if(tp == 0)
 		tp = newtlbpid(p);
+
 	tlbvirt |= PTEPID(tp);
 	putstlb(tlbvirt, tlbphys);
 	puttlb(tlbvirt, tlbphys);
@@ -131,7 +126,7 @@ purgetlb(int pid)
 	dead[pid] = 1;
 	/*
 	 * clean out all dead pids from the stlb;
-	 * garbage collect any pids with no entries
+	 * garbage collect pids with no entries
 	 */
 	memset(m->pidhere, 0, sizeof m->pidhere);
 	pidhere = m->pidhere;
@@ -178,6 +173,7 @@ putstlb(ulong tlbvirt, ulong tlbphys)
 {
 	Softtlb *entry;
 
+	/* This hash function is also coded into utlbmiss in l.s */
 	entry = &m->stb[((tlbvirt<<1) ^ (tlbvirt>>12)) & (STLBSIZE-1)];
 	entry->phys = tlbphys;
 	entry->virt = tlbvirt;
diff --git a/power/trap.c b/power/trap.c
index d9c39fdadd87b512a6403bcb998d9b6a09b513d6..0024aa621bc8c4b00dc8be0d16104313016d8acf 100644
--- a/power/trap.c
+++ b/power/trap.c
@@ -103,9 +103,10 @@ trap(Ureg *ur)
 		if(u == 0)
 			panic("fault u==0 pc %lux addr %lux", ur->pc, ur->badvaddr);
 
-		spllo();
 		x = u->p->insyscall;
 		u->p->insyscall = 1;
+
+		spllo();
 		faultmips(ur, user, ecode);
 		u->p->insyscall = x;
 		break;
@@ -165,12 +166,11 @@ trap(Ureg *ur)
 void
 intr(Ureg *ur)
 {
-	int i, any;
-	uchar xxx;
-	uchar pend, npend;
 	long v;
+	int i, any;
 	ulong cause;
 	static int bogies;
+	uchar pend, npend, xxx;
 
 	m->intr++;
 	cause = ur->cause&(INTR5|INTR4|INTR3|INTR2|INTR1);
@@ -450,7 +450,7 @@ noted(Ureg **urp, ulong arg0)
 	Ureg *nur;
 
 	nur = u->ureg;
-	if(nur->status!=u->svstatus) {
+	if(nur->status != u->svstatus) {
 		pprint("bad noted ureg status %lux\n", nur->status);
 		pexit("Suicide", 0);
 	}
@@ -505,12 +505,8 @@ syscall(Ureg *aur)
 	ur = aur;
 	p->pc = ur->pc;
 	u->dbgreg = aur;
-	ur->cause = 15<<2;		/* for debugging: system call is undef 15;
-	/*
-	 * since the system call interface does not
-	 * guarantee anything about registers, we can
-	 * smash them.  but we must save fpstatus.
-	 */
+	ur->cause = 15<<2;		/* for debugging: system call is undef 15; */
+
 	if(p->fpstate == FPactive) {
 		if((ur->status&CU1) == 0)
 			panic("syscall: FPactive but no CU1");
@@ -525,8 +521,8 @@ syscall(Ureg *aur)
 		procctl(p);
 
 	u->scallnr = ur->r1;
-	sp = ur->sp;
 	u->nerrlab = 0;
+	sp = ur->sp;
 	ret = -1;
 	if(!waserror()){
 		if(u->scallnr >= sizeof systab/sizeof systab[0]) {