diff --git a/sys/arch/pmax/include/dec_prom.h b/sys/arch/pmax/include/dec_prom.h
index 7ec31bda9da1..2aa4012dd45e 100644
--- a/sys/arch/pmax/include/dec_prom.h
+++ b/sys/arch/pmax/include/dec_prom.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: dec_prom.h,v 1.16 2001/07/30 17:05:51 mhitch Exp $	*/
+/*	$NetBSD: dec_prom.h,v 1.17 2001/08/24 15:33:17 mhitch Exp $	*/
 
 /*
  * Copyright (c) 1992, 1993
@@ -76,7 +76,7 @@
 
 #define DEC_PROM_MAGIC	0x30464354
 
-typedef struct {
+typedef struct memmap {
 	int	pagesize;	/* system page size */
 	u_char	bitmap[15360];	/* bit for each page indicating safe to use */
 } memmap;
diff --git a/sys/arch/pmax/include/vmparam.h b/sys/arch/pmax/include/vmparam.h
index 8d73b93efdbe..dfa04f57be2f 100644
--- a/sys/arch/pmax/include/vmparam.h
+++ b/sys/arch/pmax/include/vmparam.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: vmparam.h,v 1.13 2000/01/11 20:36:17 ad Exp $	*/
+/*	$NetBSD: vmparam.h,v 1.14 2001/08/24 15:33:17 mhitch Exp $	*/
 
 #ifndef _PMAX_VMPARAM_H_
 #define _PMAX_VMPARAM_H_
@@ -15,6 +15,6 @@
 #define	VM_FREELIST_DEFAULT	0
 #define	VM_FREELIST_FIRST8	1
 
-#define	VM_PHYSSEG_MAX		2
+#define	VM_PHYSSEG_MAX		16	/* 15 + 1 free lists */
 
 #endif	/* !_PMAX_VMPARAM_H_ */
diff --git a/sys/arch/pmax/pmax/dec_3max.c b/sys/arch/pmax/pmax/dec_3max.c
index 18aeef5b5d73..52e1b2ed78ad 100644
--- a/sys/arch/pmax/pmax/dec_3max.c
+++ b/sys/arch/pmax/pmax/dec_3max.c
@@ -1,4 +1,4 @@
-/* $NetBSD: dec_3max.c,v 1.33 2001/08/22 06:59:39 nisimura Exp $ */
+/* $NetBSD: dec_3max.c,v 1.34 2001/08/24 15:33:16 mhitch Exp $ */
 
 /*
  * Copyright (c) 1998 Jonathan Stone.  All rights reserved.
@@ -73,7 +73,7 @@
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: dec_3max.c,v 1.33 2001/08/22 06:59:39 nisimura Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dec_3max.c,v 1.34 2001/08/24 15:33:16 mhitch Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -115,7 +115,7 @@ dec_3max_init()
 	platform.cons_init = dec_3max_cons_init;
 	platform.iointr = dec_3max_intr;
 	platform.intr_establish = dec_3max_intr_establish;
-	platform.memsize = memsize_scan;
+	platform.memsize = memsize_bitmap;
 	/* no high resolution timer available */
 
 	/* clear any memory errors */
diff --git a/sys/arch/pmax/pmax/dec_3maxplus.c b/sys/arch/pmax/pmax/dec_3maxplus.c
index 1d978f09befe..c79652142974 100644
--- a/sys/arch/pmax/pmax/dec_3maxplus.c
+++ b/sys/arch/pmax/pmax/dec_3maxplus.c
@@ -1,4 +1,4 @@
-/* $NetBSD: dec_3maxplus.c,v 1.44 2001/08/22 06:59:40 nisimura Exp $ */
+/* $NetBSD: dec_3maxplus.c,v 1.45 2001/08/24 15:33:16 mhitch Exp $ */
 
 /*
  * Copyright (c) 1998 Jonathan Stone.  All rights reserved.
@@ -73,7 +73,7 @@
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: dec_3maxplus.c,v 1.44 2001/08/22 06:59:40 nisimura Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dec_3maxplus.c,v 1.45 2001/08/24 15:33:16 mhitch Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -123,7 +123,7 @@ dec_3maxplus_init()
 	platform.cons_init = dec_3maxplus_cons_init;
 	platform.iointr = dec_3maxplus_intr;
 	platform.intr_establish = dec_3maxplus_intr_establish;
-	platform.memsize = memsize_scan;
+	platform.memsize = memsize_bitmap;
 	platform.clkread = kn03_clkread;
 	/* 3MAX+ has IOASIC free-running high resolution timer */
 
diff --git a/sys/arch/pmax/pmax/dec_3min.c b/sys/arch/pmax/pmax/dec_3min.c
index fa4b5d0862c0..202b4307b998 100644
--- a/sys/arch/pmax/pmax/dec_3min.c
+++ b/sys/arch/pmax/pmax/dec_3min.c
@@ -1,4 +1,4 @@
-/* $NetBSD: dec_3min.c,v 1.46 2001/08/22 06:59:40 nisimura Exp $ */
+/* $NetBSD: dec_3min.c,v 1.47 2001/08/24 15:33:16 mhitch Exp $ */
 
 /*
  * Copyright (c) 1998 Jonathan Stone.  All rights reserved.
@@ -73,7 +73,7 @@
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: dec_3min.c,v 1.46 2001/08/22 06:59:40 nisimura Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dec_3min.c,v 1.47 2001/08/24 15:33:16 mhitch Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -126,7 +126,7 @@ dec_3min_init()
 	platform.cons_init = dec_3min_cons_init;
 	platform.iointr = dec_3min_intr;
 	platform.intr_establish = dec_3min_intr_establish;
-	platform.memsize = memsize_scan;
+	platform.memsize = memsize_bitmap;
 	platform.clkread = kn02ba_clkread;
 
 	/* clear any memory errors */
diff --git a/sys/arch/pmax/pmax/dec_maxine.c b/sys/arch/pmax/pmax/dec_maxine.c
index 5b067a345ba0..0a3873a8b2ea 100644
--- a/sys/arch/pmax/pmax/dec_maxine.c
+++ b/sys/arch/pmax/pmax/dec_maxine.c
@@ -1,4 +1,4 @@
-/* $NetBSD: dec_maxine.c,v 1.37 2001/08/22 06:59:41 nisimura Exp $ */
+/* $NetBSD: dec_maxine.c,v 1.38 2001/08/24 15:33:16 mhitch Exp $ */
 
 /*
  * Copyright (c) 1998 Jonathan Stone.  All rights reserved.
@@ -73,7 +73,7 @@
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: dec_maxine.c,v 1.37 2001/08/22 06:59:41 nisimura Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dec_maxine.c,v 1.38 2001/08/24 15:33:16 mhitch Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -123,7 +123,7 @@ dec_maxine_init()
 	platform.cons_init = dec_maxine_cons_init;
 	platform.iointr = dec_maxine_intr;
 	platform.intr_establish = dec_maxine_intr_establish;
-	platform.memsize = memsize_scan;
+	platform.memsize = memsize_bitmap;
 	platform.clkread = kn02ca_clkread;
 	/* MAXINE has 1 microsec. free-running high resolution timer */
  
diff --git a/sys/arch/pmax/pmax/machdep.c b/sys/arch/pmax/pmax/machdep.c
index d1c76de00a42..20852a720855 100644
--- a/sys/arch/pmax/pmax/machdep.c
+++ b/sys/arch/pmax/pmax/machdep.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: machdep.c,v 1.193 2001/08/22 06:59:42 nisimura Exp $	*/
+/*	$NetBSD: machdep.c,v 1.194 2001/08/24 15:33:16 mhitch Exp $	*/
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -43,7 +43,7 @@
  */
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.193 2001/08/22 06:59:42 nisimura Exp $");
+__KERNEL_RCSID(0, "$NetBSD: machdep.c,v 1.194 2001/08/24 15:33:16 mhitch Exp $");
 
 #include "fs_mfs.h"
 #include "opt_ddb.h"
@@ -332,14 +332,6 @@ mach_init(argc, argv, code, cv, bim, bip)
 	/* Find out how much memory is available. */
 	physmem = (*platform.memsize)(kernend);
 
-	/*
-	 * Now that we know how much memory we have, initialize the
-	 * mem cluster array.
-	 */
-	mem_clusters[0].start = 0;		/* XXX is this correct? */
-	mem_clusters[0].size  = ctob(physmem);
-	mem_cluster_cnt = 1;
-
 	/*
 	 * Load the rest of the available pages into the VM system.
 	 * Put the first 8M of RAM onto a lower-priority free list, since
@@ -347,16 +339,21 @@ mach_init(argc, argv, code, cv, bim, bip)
 	 * into this region, and we want them to have a fighting chance of
 	 * allocating their DMA memory during autoconfiguration.
 	 */
-	first = round_page(MIPS_KSEG0_TO_PHYS(kernend));
-	last = mem_clusters[0].start + mem_clusters[0].size;
-	if (last <= (8 * 1024 * 1024)) {
-		uvm_page_physload(atop(first), atop(last), atop(first),
-		    atop(last), VM_FREELIST_DEFAULT);
-	} else {
-		uvm_page_physload(atop(first), atop(8 * 1024 * 1024),
-		    atop(first), atop(8 * 1024 * 1024), VM_FREELIST_FIRST8);
-		uvm_page_physload(atop(8 * 1024 * 1024), atop(last),
-		    atop(8 * 1024 * 1024), atop(last), VM_FREELIST_DEFAULT);
+	for (i = 0, physmem = 0; i < mem_cluster_cnt; ++i) {
+		first = mem_clusters[i].start;
+		if (first == 0)
+			first = round_page(MIPS_KSEG0_TO_PHYS(kernend));
+		last = mem_clusters[i].start + mem_clusters[i].size;
+		physmem += atop(mem_clusters[i].size);
+		if (i != 0 || last <= (8 * 1024 * 1024)) {
+			uvm_page_physload(atop(first), atop(last), atop(first),
+			    atop(last), VM_FREELIST_DEFAULT);
+		} else {
+			uvm_page_physload(atop(first), atop(8 * 1024 * 1024),
+			    atop(first), atop(8 * 1024 * 1024), VM_FREELIST_FIRST8);
+			uvm_page_physload(atop(8 * 1024 * 1024), atop(last),
+			    atop(8 * 1024 * 1024), atop(last), VM_FREELIST_DEFAULT);
+		}
 	}
 
 	/*
@@ -654,6 +651,14 @@ memsize_scan(first)
 		mem++;
 	}
 
+	/*
+	 * Now that we know how much memory we have, initialize the
+	 * mem cluster array.
+	 */
+	mem_clusters[0].start = 0;		/* XXX is this correct? */
+	mem_clusters[0].size  = ctob(physmem);
+	mem_cluster_cnt = 1;
+
 	/* clear any memory error conditions possibly caused by probe */
 	(*platform.bus_reset)();
 	return (mem);
@@ -666,8 +671,38 @@ int
 memsize_bitmap(first)
 	caddr_t first;
 {
+	memmap *prom_memmap = (memmap *)first;
+	int i, mapbytes;
+	int segstart, curaddr, xsize, segnum;
 
-	panic("memsize_bitmap not implemented");
+	mapbytes = prom_getbitmap(prom_memmap);
+	if (mapbytes == 0)
+		return (memsize_scan(first));
+
+	segstart = curaddr = i = segnum = 0;
+	xsize = prom_memmap->pagesize * 8;
+	while (i < mapbytes) {
+		while (prom_memmap->bitmap[i] == 0xff && i < mapbytes) {
+			++i;
+			curaddr += xsize;
+		}
+		if (curaddr > segstart) {
+			mem_clusters[segnum].start = segstart;
+			mem_clusters[segnum].size = curaddr - segstart;
+			++segnum;
+		}
+		while (i < mapbytes && prom_memmap->bitmap[i] != 0xff) {
+			++i;
+			curaddr += xsize;
+		}
+		segstart = curaddr;
+	}
+	mem_cluster_cnt = segnum;
+	for (i = 0; i < segnum; ++i) {
+		printf("segment %2d start %08lx size %08lx\n", i,
+		    (long)mem_clusters[i].start, (long)mem_clusters[i].size);
+	}
+	return (mapbytes * 8);
 }
 
 /*
diff --git a/sys/arch/pmax/pmax/machdep.h b/sys/arch/pmax/pmax/machdep.h
index 1100c79328cd..19ca7e0720c5 100644
--- a/sys/arch/pmax/pmax/machdep.h
+++ b/sys/arch/pmax/pmax/machdep.h
@@ -1,4 +1,4 @@
-/* $NetBSD: machdep.h,v 1.8 2000/03/28 23:57:30 simonb Exp $ */
+/* $NetBSD: machdep.h,v 1.9 2001/08/24 15:33:17 mhitch Exp $ */
 
 /*
  * Copyright (c) 1998 Jonathan Stone.  All rights reserved.
@@ -33,6 +33,8 @@
 /* max memory for a model */
 extern	int physmem_boardmax;	/* {model,simm}-specific bound on physmem */
 
+struct memmap;
+
 /* PROM callback routines - see pmax/promcall.c */
 void	 prom_findcons __P((int *, int *, int *));
 void	 prom_halt __P((int, char *)) __attribute__((__noreturn__));
@@ -40,3 +42,4 @@ void	 prom_haltbutton __P((void));
 int	 prom_scsiid __P((int));
 char	*prom_getenv __P((char *));
 int	 prom_systype __P((void));
+int	 prom_getbitmap __P((struct memmap *));
diff --git a/sys/arch/pmax/pmax/promcall.c b/sys/arch/pmax/pmax/promcall.c
index 64945613a9bf..6ccc943ebbc2 100644
--- a/sys/arch/pmax/pmax/promcall.c
+++ b/sys/arch/pmax/pmax/promcall.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: promcall.c,v 1.7 2000/03/30 14:45:13 simonb Exp $	*/
+/*	$NetBSD: promcall.c,v 1.8 2001/08/24 15:33:17 mhitch Exp $	*/
 
 /*
  * Copyright (c) 1988 University of Utah.
@@ -43,7 +43,7 @@
  */
 
 #include <sys/cdefs.h>			/* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: promcall.c,v 1.7 2000/03/30 14:45:13 simonb Exp $");
+__KERNEL_RCSID(0, "$NetBSD: promcall.c,v 1.8 2001/08/24 15:33:17 mhitch Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -234,3 +234,30 @@ prom_scsiid(cnum)
 	cp = prom_getenv(scsiid_var);
 	return (cp != NULL) ? strtoul(cp, NULL, 0) : DEFAULT_SCSIID;
 }
+
+/*
+ * Get the memory bitmap from the PROM if we can
+ */
+int
+prom_getbitmap(map)
+	struct memmap *map;
+{
+	char *cp;
+	int len;
+
+	if (callv->_getbitmap != NULL)
+		return (callv->_getbitmap(map));
+	/*
+	 * See if we can get the bitmap from the environment variables
+	 */
+	cp = prom_getenv("bitmaplen");
+	if (cp == NULL)
+		return (0);
+	len = (int)strtoul(cp, NULL, 0) * 4;
+	cp = prom_getenv("bitmap");
+	if (cp == NULL)
+		return (0);
+	bcopy((char *)strtoul(cp, NULL, 0), &map->bitmap, len);
+	map->pagesize = 4096;
+	return (len);
+}