diff --git a/commands/autopart/autopart.c b/commands/autopart/autopart.c
index 4d6a85cb0..00146098d 100644
--- a/commands/autopart/autopart.c
+++ b/commands/autopart/autopart.c
@@ -27,7 +27,6 @@
 #include <minix/config.h>
 #include <minix/const.h>
 #include <minix/partition.h>
-#include <minix/u64.h>
 #include <minix/com.h>
 #include <machine/partition.h>
 #include <termios.h>
@@ -525,8 +524,10 @@ void geometry(void)
 		if (ioctl(device, DIOCGETP, &geometry) < 0)
 			err= errno;
 		else {
-			table[0].lowsec= div64u(geometry.base, SECTOR_SIZE);
-			table[0].size= div64u(geometry.size, SECTOR_SIZE);
+			table[0].lowsec= (unsigned long)(geometry.base / 
+							SECTOR_SIZE);
+			table[0].size  = (unsigned long)(geometry.size / 
+							SECTOR_SIZE);
 			cylinders= geometry.cylinders;
 			heads= geometry.heads;
 			sectors= geometry.sectors;
@@ -578,8 +579,8 @@ exit(1);
 	 * This makes sense for subpartitioning primary partitions.
 	 */
 	if (precise && ioctl(device, DIOCGETP, &geometry) >= 0) {
-		table[0].lowsec= div64u(geometry.base, SECTOR_SIZE);
-		table[0].size= div64u(geometry.size, SECTOR_SIZE);
+		table[0].lowsec= (unsigned long)(geometry.base / SECTOR_SIZE);
+		table[0].size  = (unsigned long)(geometry.size / SECTOR_SIZE);
 	} else {
 		precise= 0;
 	}
@@ -2149,8 +2150,8 @@ sanitycheck_failed(char *dev, struct part_entry *pe)
 
 	close(fd);
 
-	it_lowsec = div64u(part.base, SECTOR_SIZE);
-	it_secsize = div64u(part.size, SECTOR_SIZE);
+	it_lowsec  = (unsigned long)(part.base / SECTOR_SIZE);
+	it_secsize = (unsigned long)(part.size / SECTOR_SIZE);
 
 	if(it_lowsec != pe->lowsec || it_secsize != pe->size) {
 		fprintf(stderr, "\nReturned and set numbers don't match up!\n");
diff --git a/commands/fsck.mfs/fsck.c b/commands/fsck.mfs/fsck.c
index f302b9dea..3cf242dcb 100644
--- a/commands/fsck.mfs/fsck.c
+++ b/commands/fsck.mfs/fsck.c
@@ -46,7 +46,6 @@
 #include <minix/config.h>
 #include <minix/const.h>
 #include <minix/type.h>
-#include <minix/u64.h>
 #include "mfs/const.h"
 #include "mfs/inode.h"
 #include "mfs/type.h"
@@ -97,7 +96,7 @@ static struct super_block sb;
  * btoa64 gives the byte address of a block
  */
 #define ztob(z)		((block_nr) (z) << sb.s_log_zone_size)
-#define btoa64(b)	(mul64u(b, block_size))
+#define btoa64(b)	((u64_t)(b) * block_size)
 #define SCALE		((int) ztob(1))	/* # blocks in a zone */
 #define FIRST		((zone_nr) sb.s_firstdatazone)	/* as the name says */
 
@@ -656,12 +655,12 @@ void chksuper()
 
 int inoblock(int inn)
 {
-  return div64u(mul64u(inn - 1, INODE_SIZE), block_size) + BLK_ILIST;
+  return (int)(((u64_t)(inn - 1) * INODE_SIZE) / block_size) + BLK_ILIST;
 }
 
 int inooff(int inn)
 {
-  return rem64u(mul64u(inn - 1, INODE_SIZE), block_size);
+  return (int)(((u64_t)(inn - 1) * INODE_SIZE) % block_size);
 }
 
 /* Make a listing of the inodes given by `clist'.  If `repair' is set, ask
diff --git a/commands/part/part.c b/commands/part/part.c
index d141d8553..2bf169cf9 100644
--- a/commands/part/part.c
+++ b/commands/part/part.c
@@ -22,7 +22,6 @@
 #include <minix/config.h>
 #include <minix/const.h>
 #include <minix/partition.h>
-#include <minix/u64.h>
 #include <machine/partition.h>
 #include <termios.h>
 
@@ -477,8 +476,10 @@ void geometry(void)
 		if (ioctl(device, DIOCGETP, &geometry) < 0)
 			err= errno;
 		else {
-			table[0].lowsec= div64u(geometry.base, SECTOR_SIZE);
-			table[0].size= div64u(geometry.size, SECTOR_SIZE);
+			table[0].lowsec= (unsigned long)(geometry.base / 
+							SECTOR_SIZE);
+			table[0].size=   (unsigned long)(geometry.size / 
+							SECTOR_SIZE);
 			cylinders= geometry.cylinders;
 			heads= geometry.heads;
 			sectors= geometry.sectors;
@@ -546,8 +547,8 @@ void geometry(void)
 	 * This makes sense for subpartitioning primary partitions.
 	 */
 	if (precise && ioctl(device, DIOCGETP, &geometry) >= 0) {
-		table[0].lowsec= div64u(geometry.base, SECTOR_SIZE);
-		table[0].size= div64u(geometry.size, SECTOR_SIZE);
+		table[0].lowsec= (unsigned long)(geometry.base / SECTOR_SIZE);
+		table[0].size  = (unsigned long)(geometry.size / SECTOR_SIZE);
 	} else {
 		precise= 0;
 	}
diff --git a/commands/partition/partition.c b/commands/partition/partition.c
index c3b2afd12..c012d3b2f 100644
--- a/commands/partition/partition.c
+++ b/commands/partition/partition.c
@@ -20,7 +20,6 @@
 #include <minix/config.h>
 #include <minix/const.h>
 #include <minix/partition.h>
-#include <minix/u64.h>
 #else
 #include "partition.h"
 #define NR_PARTITIONS 4
@@ -322,8 +321,8 @@ void geometry(void)
 		geometry.cylinders= (sb.st_size-1)/SECTOR_SIZE/
 			(geometry.sectors*geometry.heads) + 1;
 	}
-	primary.lowsec= div64u(geometry.base, SECTOR_SIZE);
-	primary.size= div64u(geometry.size, SECTOR_SIZE);
+	primary.lowsec= (unsigned long)(geometry.base / SECTOR_SIZE);
+	primary.size  = (unsigned long)(geometry.size / SECTOR_SIZE);
 	cylinders= geometry.cylinders;
 	heads= geometry.heads;
 	sectors= geometry.sectors;
diff --git a/commands/time/time.c b/commands/time/time.c
index 651d244c6..b951312bf 100644
--- a/commands/time/time.c
+++ b/commands/time/time.c
@@ -11,7 +11,6 @@
 #include <unistd.h>
 #include <sys/wait.h>
 #include <minix/minlib.h>
-// #include <minix/u64.h>
 #include <stdio.h>
 
 /* -DNEW prints time to 0.01 sec. */
diff --git a/commands/vol/vol.c b/commands/vol/vol.c
index 845c08a45..3f87c5304 100644
--- a/commands/vol/vol.c
+++ b/commands/vol/vol.c
@@ -27,7 +27,6 @@
 #include <sys/ioctl.h>
 #include <sys/mtio.h>
 #include <minix/partition.h>
-#include <minix/u64.h>
 
 /* Preferred block size to variable block length tapes, block devices or files.
  */
diff --git a/drivers/fbd/rule.c b/drivers/fbd/rule.c
index f5c140b17..2eb12ae51 100644
--- a/drivers/fbd/rule.c
+++ b/drivers/fbd/rule.c
@@ -92,8 +92,8 @@ static int rule_match(struct fbd_rule *rule, u64_t pos, size_t size, int flag)
 	 */
 
 	/* Ranges must overlap (start < pos+size && end > pos). */
-	if (cmp64(rule->start, pos + size) >= 0 ||
-			(cmp64u(rule->end, 0) && cmp64(rule->end, pos) <= 0))
+	if (rule->start >= pos + size ||
+			(rule->end != 0 && rule->end <= pos))
 		return FALSE;
 
 	/* Flags must match. */
diff --git a/drivers/filter/main.c b/drivers/filter/main.c
index 75a3a9379..bc15aedcb 100644
--- a/drivers/filter/main.c
+++ b/drivers/filter/main.c
@@ -155,7 +155,7 @@ static ssize_t filter_transfer(devminor_t UNUSED(minor), int do_write,
 	for(size = 0, i = 0; i < count; i++)
 		size += iov[i].iov_size;
 
-	if (rem64u(pos, SECTOR_SIZE) != 0 || size % SECTOR_SIZE != 0) {
+	if (pos % SECTOR_SIZE != 0 || size % SECTOR_SIZE != 0) {
 		printf("Filter: unaligned request from caller!\n");
 		return EINVAL;
 	}
diff --git a/drivers/filter/sum.c b/drivers/filter/sum.c
index 5fe581c2e..236100b68 100644
--- a/drivers/filter/sum.c
+++ b/drivers/filter/sum.c
@@ -8,8 +8,8 @@
 #define SEC2SUM_NR(nr)	((nr)/NR_SUM_SEC*(NR_SUM_SEC+1) + NR_SUM_SEC)
 #define LOG2PHYS(nr)	((nr)/NR_SUM_SEC*(NR_SUM_SEC+1) + (nr)%NR_SUM_SEC)
 
-#define POS2SEC(nr)	div64u((nr), SECTOR_SIZE)
-#define SEC2POS(nr)	mul64u((nr), SECTOR_SIZE)
+#define POS2SEC(nr)	(unsigned long)((nr) / SECTOR_SIZE)
+#define SEC2POS(nr)	((u64_t)(nr) * SECTOR_SIZE)
 
 /* Data buffers. */
 static char *ext_array, *ext_buffer;	/* interspersed buffer */
diff --git a/drivers/floppy/floppy.c b/drivers/floppy/floppy.c
index 1b95108dc..698b96d07 100644
--- a/drivers/floppy/floppy.c
+++ b/drivers/floppy/floppy.c
@@ -406,8 +406,8 @@ static struct device *f_prepare(devminor_t device)
   if (f_fp->fl_density < NT) {
 	f_dp = &fdensity[f_fp->fl_density];
 	f_sectors = f_dp->secpt;
-	f_fp->fl_geom.dv_size = mul64u((long) (NR_HEADS * f_sectors
-					* f_dp->cyls), SECTOR_SIZE);
+	f_fp->fl_geom.dv_size = (u64_t)(NR_HEADS * f_sectors * f_dp->cyls) * 
+								SECTOR_SIZE;
   }
 
   /* A partition? */
@@ -496,7 +496,7 @@ static ssize_t f_transfer(
 	/* Which block on disk and how close to EOF? */
 	if (position >= dv_size) return(total);		/* At EOF */
 	if (position + nbytes > dv_size) nbytes = dv_size - position;
-	block = div64u(f_dv->dv_base + position, SECTOR_SIZE);
+	block = (unsigned long)((f_dv->dv_base + position) / SECTOR_SIZE);
 
 	if ((nbytes & SECTOR_MASK) != 0) return(EINVAL);
 
diff --git a/include/minix/timers.h b/include/minix/timers.h
index 482975e29..44c039791 100644
--- a/include/minix/timers.h
+++ b/include/minix/timers.h
@@ -84,7 +84,7 @@ clock_t tmrs_settimer(minix_timer_t **tmrs, minix_timer_t *tp, clock_t exp_time,
 	read_tsc_64(&_starttime);				\
 	do { timed_code_block } while(0);			\
 	read_tsc_64(&_endtime);					\
-	_dt = sub64(_endtime, _starttime);			\
+	_dt = _endtime - _starttime;				\
 	if(_cum_instances == 0) {				\
 		RESET_STATS(_starttime, _cum_instances, _cum_spenttime, _cum_starttime); \
 	 }							\
@@ -95,8 +95,8 @@ clock_t tmrs_settimer(minix_timer_t **tmrs, minix_timer_t *tp, clock_t exp_time,
 	} 							\
 	_cum_spenttime = add64(_cum_spenttime, _dt);		\
 	_cum_instances++;					\
-	_cum_dt = sub64(_endtime, _cum_starttime);		\
-	if(cmp64(_cum_dt, make64(0, 120)) > 0) {		\
+	_cum_dt = _endtime - _cum_starttime;			\
+	if(_cum_dt > make64(0, 120)) {				\
 		PRINT_STATS(_cum_spenttime, _cum_instances);	\
 		RESET_STATS(_starttime, _cum_instances, _cum_spenttime, _cum_starttime); 	\
 	} 							\
diff --git a/include/minix/u64.h b/include/minix/u64.h
index 5411aa399..6cc8bed6a 100644
--- a/include/minix/u64.h
+++ b/include/minix/u64.h
@@ -7,81 +7,6 @@
 
 #include <sys/types.h>
 
-#include <limits.h>
-
-static inline int bsr64(u64_t i)
-{
-	int index;
-	u64_t mask;
-
-	for (index = 63, mask = 1ULL << 63; index >= 0; --index, mask >>= 1) {
-	    if (i & mask)
-		return index;
-	}
-
-	return -1;
-}
-
-static inline int cmp64(u64_t i, u64_t j)
-{
-	if (i > j)
-		return 1;
-	else if (i < j)
-		return -1;
-	else /* (i == j) */
-		return 0;
-}
-
-static inline int cmp64u(u64_t i, unsigned j)
-{
-	if (i > j)
-		return 1;
-	else if (i < j)
-		return -1;
-	else /* (i == j) */
-		return 0;
-}
-
-static inline int cmp64ul(u64_t i, unsigned long j)
-{
-	if (i > j)
-		return 1;
-	else if (i < j)
-		return -1;
-	else /* (i == j) */
-		return 0;
-}
-
-static inline unsigned diff64(u64_t i, u64_t j)
-{
-	return (unsigned)(i - j);
-}
-
-static inline u64_t div64(u64_t i, u64_t j)
-{
-        return i / j;
-}
-
-static inline u64_t rem64(u64_t i, u64_t j)
-{
-	return i % j;
-}
-
-static inline unsigned long div64u(u64_t i, unsigned j)
-{
-	return (unsigned long)(i / j);
-}
-
-static inline u64_t div64u64(u64_t i, unsigned j)
-{
-	return i / j;
-}
-
-static inline unsigned rem64u(u64_t i, unsigned j)
-{
-	return (unsigned)(i % j);
-}
-
 static inline unsigned long ex64lo(u64_t i)
 {
 	return (unsigned long)i;
@@ -97,35 +22,4 @@ static inline u64_t make64(unsigned long lo, unsigned long hi)
 	return ((u64_t)hi << 32) | (u64_t)lo;
 }
 
-static inline u64_t mul64(u64_t i, u64_t j)
-{
-	return i * j;
-}
-
-static inline u64_t mul64u(unsigned long i, unsigned j)
-{
-	return (u64_t)i * j;
-}
-
-static inline u64_t sub64(u64_t i, u64_t j)
-{
-	return i - j;
-}
-
-static inline u64_t sub64u(u64_t i, unsigned j)
-{
-	return i - j;
-}
-
-static inline u64_t sub64ul(u64_t i, unsigned long j)
-{
-	return i - j;
-}
-
-u64_t rrotate64(u64_t x, unsigned short b);
-u64_t rshift64(u64_t x, unsigned short b);
-u64_t xor64(u64_t a, u64_t b);
-u64_t and64(u64_t a, u64_t b);
-u64_t not64(u64_t a);
-
 #endif /* _MINIX__U64_H */
diff --git a/kernel/arch/earm/arch_clock.c b/kernel/arch/earm/arch_clock.c
index c8b87d166..8990890c4 100644
--- a/kernel/arch/earm/arch_clock.c
+++ b/kernel/arch/earm/arch_clock.c
@@ -127,12 +127,12 @@ int register_local_timer_handler(const irq_handler_t handler)
 
 u64_t ms_2_cpu_time(unsigned ms)
 {
-	return mul64u(tsc_per_ms[cpuid], ms);
+	return (u64_t)(tsc_per_ms[cpuid]) * ms;
 }
 
 unsigned cpu_time_2_ms(u64_t cpu_time)
 {
-	return div64u(cpu_time, tsc_per_ms[cpuid]);
+	return (unsigned long)(cpu_time / tsc_per_ms[cpuid]);
 }
 
 short cpu_load(void)
diff --git a/kernel/arch/i386/apic.c b/kernel/arch/i386/apic.c
index 9ec3190c2..4c5ec5d9a 100644
--- a/kernel/arch/i386/apic.c
+++ b/kernel/arch/i386/apic.c
@@ -515,14 +515,14 @@ static void apic_calibrate_clocks(unsigned cpu)
 	rm_irq_handler(&spurious_irq);
 
 	lapic_delta = lapic_tctr0 - lapic_tctr1;
-	tsc_delta = sub64(tsc1, tsc0);
+	tsc_delta = tsc1 - tsc0;
 
 	lapic_bus_freq[cpuid] = system_hz * lapic_delta / (PROBE_TICKS - 1);
 	BOOT_VERBOSE(printf("APIC bus freq %u MHz\n",
 				lapic_bus_freq[cpuid] / 1000000));
-	cpu_freq = mul64(div64u64(tsc_delta, PROBE_TICKS - 1), make64(system_hz, 0));
+	cpu_freq = (tsc_delta / (PROBE_TICKS - 1)) * make64(system_hz, 0);
 	cpu_set_freq(cpuid, cpu_freq);
-	cpu_info[cpuid].freq = div64u(cpu_freq, 1000000);
+	cpu_info[cpuid].freq = (unsigned long)(cpu_freq / 1000000);
 	BOOT_VERBOSE(cpu_print_freq(cpuid));
 }
 
diff --git a/kernel/arch/i386/arch_watchdog.c b/kernel/arch/i386/arch_watchdog.c
index 4dd3dcc8d..58b76159d 100644
--- a/kernel/arch/i386/arch_watchdog.c
+++ b/kernel/arch/i386/arch_watchdog.c
@@ -33,7 +33,7 @@ static void intel_arch_watchdog_init(const unsigned cpu)
 	 */
 	cpuf = cpu_get_freq(cpu);
 	while (ex64hi(cpuf) || ex64lo(cpuf) > 0x7fffffffU)
-		cpuf = div64u64(cpuf, 2);
+		cpuf /= 2;
 	cpuf = make64(-ex64lo(cpuf), ex64hi(cpuf));
 	watchdog->resetval = watchdog->watchdog_resetval = cpuf;
 
@@ -159,7 +159,7 @@ static int intel_arch_watchdog_profile_init(const unsigned freq)
 
 	/* FIXME works only if all CPUs have the same freq */
 	cpuf = cpu_get_freq(cpuid);
-	cpuf = div64u64(cpuf, freq);
+	cpuf /= freq;
 
 	/*
 	 * if freq is too low and the cpu freq too high we may get in a range of
@@ -223,7 +223,7 @@ static int amd_watchdog_profile_init(const unsigned freq)
 
 	/* FIXME works only if all CPUs have the same freq */
 	cpuf = cpu_get_freq(cpuid);
-	cpuf = -div64u64(cpuf, freq);
+	cpuf = -cpuf / freq;
 
 	watchdog->profile_resetval = cpuf;
 
diff --git a/kernel/main.c b/kernel/main.c
index f309ea6f8..6665894fd 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -500,7 +500,7 @@ void cpu_print_freq(unsigned cpu)
         u64_t freq;
 
         freq = cpu_get_freq(cpu);
-        printf("CPU %d freq %lu MHz\n", cpu, div64u(freq, 1000000));
+        printf("CPU %d freq %lu MHz\n", cpu, (unsigned long)(freq / 1000000));
 }
 
 int is_fpu(void)
diff --git a/lib/libblockdriver/driver.c b/lib/libblockdriver/driver.c
index ed251702f..02805297a 100644
--- a/lib/libblockdriver/driver.c
+++ b/lib/libblockdriver/driver.c
@@ -293,7 +293,8 @@ static int do_dioctl(struct blockdriver *bdp, dev_t minor,
 		(*bdp->bdr_geometry)(minor, &entry);
 	} else {
 		/* The driver doesn't care -- make up fake geometry. */
-		entry.cylinders = div64u(entry.size, SECTOR_SIZE) / (64 * 32);
+		entry.cylinders = (unsigned long)(entry.size / SECTOR_SIZE) / 
+								  (64 * 32);
 		entry.heads = 64;
 		entry.sectors = 32;
 	}
diff --git a/lib/libblockdriver/drvlib.c b/lib/libblockdriver/drvlib.c
index 55df9f00d..c2e57089f 100644
--- a/lib/libblockdriver/drvlib.c
+++ b/lib/libblockdriver/drvlib.c
@@ -72,9 +72,9 @@ u8_t *tmp_buf;			/* temporary buffer */
 
   /* Get the geometry of the device to partition */
   if ((dv = (*bdp->bdr_part)(device)) == NULL
-				|| cmp64u(dv->dv_size, 0) == 0) return;
-  base = div64u(dv->dv_base, SECTOR_SIZE);
-  limit = base + div64u(dv->dv_size, SECTOR_SIZE);
+				|| dv->dv_size == 0) return;
+  base = (unsigned long)(dv->dv_base / SECTOR_SIZE);
+  limit = base + (unsigned long)(dv->dv_size / SECTOR_SIZE);
 
   /* Read the partition table for the device. */
   if(!get_part_table(bdp, device, 0L, table, tmp_buf)) {
@@ -109,8 +109,8 @@ u8_t *tmp_buf;			/* temporary buffer */
 	if (pe->lowsec < base) pe->lowsec = base;
 	if (part_limit < pe->lowsec) part_limit = pe->lowsec;
 
-	dv->dv_base = mul64u(pe->lowsec, SECTOR_SIZE);
-	dv->dv_size = mul64u(part_limit - pe->lowsec, SECTOR_SIZE);
+	dv->dv_base = (u64_t)pe->lowsec * SECTOR_SIZE;
+	dv->dv_size = (u64_t)(part_limit - pe->lowsec) * SECTOR_SIZE;
 
 	if (style == P_PRIMARY) {
 		/* Each Minix primary partition can be subpartitioned. */
@@ -163,9 +163,9 @@ u8_t *tmp_buf;			/* temporary buffer */
 		if (pe->sysind != NO_PART) {
 			if ((dv = (*bdp->bdr_part)(subdev)) == NULL) return;
 
-			dv->dv_base = mul64u(extbase + offset + pe->lowsec,
-								SECTOR_SIZE);
-			dv->dv_size = mul64u(pe->size, SECTOR_SIZE);
+			dv->dv_base = (u64_t)(extbase + offset + pe->lowsec) *
+								SECTOR_SIZE;
+			dv->dv_size = (u64_t)pe->size * SECTOR_SIZE;
 
 			/* Out of devices? */
 			if (++subdev % NR_PARTITIONS == 0) return;
@@ -191,7 +191,7 @@ u8_t *tmp_buf;			/* temporary buffer */
   u64_t position;
   int r;
 
-  position = mul64u(offset, SECTOR_SIZE);
+  position = (u64_t)offset * SECTOR_SIZE;
   iovec1.iov_addr = (vir_bytes) tmp_buf;
   iovec1.iov_size = CD_SECTOR_SIZE;
   r = (*bdp->bdr_transfer)(device, FALSE /*do_write*/, position, SELF,
diff --git a/lib/libblockdriver/trace.c b/lib/libblockdriver/trace.c
index 555470266..92f7e6ac9 100644
--- a/lib/libblockdriver/trace.c
+++ b/lib/libblockdriver/trace.c
@@ -40,7 +40,7 @@ static u32_t trace_gettime(void)
 
   read_tsc_64(&tsc);
 
-  tsc = sub64(tsc, trace_tsc);
+  tsc -= trace_tsc;
 
   return tsc_64_to_micros(tsc);
 }
diff --git a/lib/libhgfs/time.c b/lib/libhgfs/time.c
index ba3085f14..1767db276 100644
--- a/lib/libhgfs/time.c
+++ b/lib/libhgfs/time.c
@@ -18,7 +18,7 @@ void time_init(void)
    * the difference between that time and the UNIX epoch, in 100ns units.
    */
   /* FIXME: we currently do not take into account timezones. */
-  time_offset = mul64u(116444736, 1000000000);
+  time_offset = (u64_t)116444736 * 1000000000;
 }
 
 /*===========================================================================*
@@ -33,7 +33,7 @@ void time_put(struct timespec *tsp)
   u64_t hgfstime;
 
   if (tsp != NULL) {
-	hgfstime = mul64u(tsp->tv_sec, 10000000) + (tsp->tv_nsec / 100);
+	hgfstime = ((u64_t)tsp->tv_sec * 10000000) + (tsp->tv_nsec / 100);
 	hgfstime += time_offset;
 
 	RPC_NEXT32 = ex64lo(hgfstime);
@@ -60,10 +60,10 @@ void time_get(struct timespec *tsp)
 	time_lo = RPC_NEXT32;
 	time_hi = RPC_NEXT32;
 
-	hgfstime = sub64(make64(time_lo, time_hi), time_offset);
+	hgfstime = make64(time_lo, time_hi) - time_offset;
 
-	tsp->tv_sec = div64u(hgfstime, 10000000);
-	tsp->tv_nsec = rem64u(hgfstime, 10000000) * 100;
+	tsp->tv_sec  = (unsigned long)(hgfstime / 10000000);
+	tsp->tv_nsec = (unsigned)(hgfstime % 10000000) * 100;
   }
   else RPC_ADVANCE(sizeof(u32_t) * 2);
 }
diff --git a/lib/libminixfs/cache.c b/lib/libminixfs/cache.c
index 6e16ce19e..38f9b2a7c 100644
--- a/lib/libminixfs/cache.c
+++ b/lib/libminixfs/cache.c
@@ -76,8 +76,8 @@ static u32_t fs_bufs_heuristic(int minbufs, u32_t btotal, u64_t bfree,
 	vsi.vsi_pagesize / 1024;
 
   /* check fs usage. */
-  kbytes_used_fs = div64u(mul64u(bused, blocksize), 1024);
-  kbytes_total_fs = div64u(mul64u(btotal, blocksize), 1024);
+  kbytes_used_fs  = (unsigned long)(((u64_t)bused * blocksize) / 1024);
+  kbytes_total_fs = (unsigned long)(((u64_t)btotal * blocksize) / 1024);
 
   /* heuristic for a desired cache size based on FS usage;
    * but never bigger than half of the total filesystem
@@ -518,7 +518,7 @@ register struct buf *bp;	/* buffer pointer */
   ASSERT(bp->lmfs_bytes == fs_block_size);
   ASSERT(fs_block_size > 0);
 
-  pos = mul64u(bp->lmfs_blocknr, fs_block_size);
+  pos = (u64_t)bp->lmfs_blocknr * fs_block_size;
   if(fs_block_size > PAGE_SIZE) {
 #define MAXPAGES 20
 	vir_bytes blockrem, vaddr = (vir_bytes) bp->data;
@@ -704,7 +704,7 @@ void lmfs_rw_scattered(
 	assert(nblocks > 0);
 	assert(niovecs > 0);
 
-	pos = mul64u(bufq[0]->lmfs_blocknr, fs_block_size);
+	pos = (u64_t)bufq[0]->lmfs_blocknr * fs_block_size;
 	if (rw_flag == READING)
 		r = bdev_gather(dev, pos, iovec, niovecs, BDEV_NOFLAGS);
 	else
diff --git a/lib/libminlib/Makefile b/lib/libminlib/Makefile
index 102984a97..2ab9a2dc2 100644
--- a/lib/libminlib/Makefile
+++ b/lib/libminlib/Makefile
@@ -19,7 +19,7 @@ SRCS+= dhcp_gettag.c dhcp_settag.c
 SRCS+= gcov.c gcov_flush.c
 
 # Various utils
-SRCS+= itoa.c u64util.c read_tsc_64.c
+SRCS+= itoa.c read_tsc_64.c
 
 # servxcheck
 SRCS+= servxcheck.c
diff --git a/lib/libminlib/u64util.c b/lib/libminlib/u64util.c
deleted file mode 100644
index bcddb067f..000000000
--- a/lib/libminlib/u64util.c
+++ /dev/null
@@ -1,34 +0,0 @@
-/* Few u64 utils implemented in C
- * Author: Gautam BT
- */
-#include <minix/u64.h>
-
-u64_t rrotate64(u64_t x, unsigned short b)
-{
-	b %= 64;
-	if ((b &= 63) == 0)
-		return x;
-	return (x >> b) | (x << (64 - b));
-}
-
-u64_t rshift64(u64_t x, unsigned short b)
-{
-	if (b >= 64)
-		return 0;
-	return x >> b;
-}
-
-u64_t xor64(u64_t a, u64_t b)
-{
-	return a ^ b;
-}
-
-u64_t and64(u64_t a, u64_t b)
-{
-	return a & b;
-}
-
-u64_t not64(u64_t a)
-{
-	return ~a;
-}
diff --git a/lib/libsffs/misc.c b/lib/libsffs/misc.c
index 89d43b19c..17455dc5b 100644
--- a/lib/libsffs/misc.c
+++ b/lib/libsffs/misc.c
@@ -47,8 +47,8 @@ int do_statvfs()
   statvfs.f_bsize = BLOCK_SIZE;
   statvfs.f_frsize = BLOCK_SIZE;
   statvfs.f_iosize = BLOCK_SIZE;
-  statvfs.f_blocks = div64u(total, BLOCK_SIZE);
-  statvfs.f_bfree = div64u(free, BLOCK_SIZE);
+  statvfs.f_blocks = (unsigned long)(total / BLOCK_SIZE);
+  statvfs.f_bfree = (unsigned long)(free / BLOCK_SIZE);
   statvfs.f_bavail = statvfs.f_bfree;
   statvfs.f_namemax = NAME_MAX;
 
diff --git a/lib/libsffs/stat.c b/lib/libsffs/stat.c
index e3b1afd62..7ac386926 100644
--- a/lib/libsffs/stat.c
+++ b/lib/libsffs/stat.c
@@ -70,7 +70,7 @@ int do_stat()
   stat.st_uid = sffs_params->p_uid;
   stat.st_gid = sffs_params->p_gid;
   stat.st_rdev = NO_DEV;
-  if (cmp64u(attr.a_size, LONG_MAX) > 0)
+  if (attr.a_size > LONG_MAX)
 	stat.st_size = LONG_MAX;
   else
 	stat.st_size = ex64lo(attr.a_size);
diff --git a/lib/libsffs/write.c b/lib/libsffs/write.c
index bd571a337..3bdc209c3 100644
--- a/lib/libsffs/write.c
+++ b/lib/libsffs/write.c
@@ -138,7 +138,7 @@ int do_ftrunc()
   start = make64(m_in.REQ_TRC_START_LO, m_in.REQ_TRC_START_HI);
   end = make64(m_in.REQ_TRC_END_LO, m_in.REQ_TRC_END_HI);
 
-  if (cmp64u(end, 0) == 0) {
+  if (end == 0) {
 	/* Truncate or expand the file. */
 	if ((r = verify_inode(ino, path, NULL)) != OK)
 		return r;
@@ -149,9 +149,9 @@ int do_ftrunc()
 	r = sffs_table->t_setattr(path, &attr);
   } else {
 	/* Write zeroes to the file. We can't create holes. */
-	if (cmp64(end, start) <= 0) return EINVAL;
+	if (end <= start) return EINVAL;
 
-	delta = sub64(end, start);
+	delta = end - start;
 
 	if (ex64hi(delta) != 0) return EINVAL;
 
diff --git a/lib/libsys/arch/i386/getidle.c b/lib/libsys/arch/i386/getidle.c
index 8fc225e7c..566305211 100644
--- a/lib/libsys/arch/i386/getidle.c
+++ b/lib/libsys/arch/i386/getidle.c
@@ -67,10 +67,10 @@ double getidle(void)
 	if ((r = sys_getidletsc(&idle2)) != OK)
 		return -1.0;
 
-	idelta = sub64(idle2, idle);
-	tdelta = sub64(stop, start);
+	idelta = idle2 - idle;
+	tdelta = stop - start;
 
-	if (cmp64(idelta, tdelta) >= 0)
+	if (idelta >= tdelta)
 		return 100.0;
 
 	ifp = make_double(idelta);
diff --git a/lib/libsys/arch/i386/profile.c b/lib/libsys/arch/i386/profile.c
index 6f795c1fc..667733977 100644
--- a/lib/libsys/arch/i386/profile.c
+++ b/lib/libsys/arch/i386/profile.c
@@ -191,9 +191,9 @@ void procexit (char *UNUSED(name))
    */
 
   /* Calculate "small" difference. */
-  spent = sub64(stop, cprof_stk[cprof_stk_top].start_2);
+  spent = stop - cprof_stk[cprof_stk_top].start_2;
   cprof_stk[cprof_stk_top].slot->cycles +=
-	sub64(spent, cprof_stk[cprof_stk_top].spent_deeper);
+	spent - cprof_stk[cprof_stk_top].spent_deeper;
 
   /* Clear spent_deeper for call level we're leaving. */
   cprof_stk[cprof_stk_top].spent_deeper = ((u64_t)(0));
@@ -216,7 +216,7 @@ void procexit (char *UNUSED(name))
   stop = make64(tsc_lo, tsc_hi);
 
   /* Calculate "big" difference. */
-  spent = sub64(stop, cprof_stk[cprof_stk_top].start_1);
+  spent = stop - cprof_stk[cprof_stk_top].start_1;
   cprof_stk_top--;					/* decrease stack */
   if (cprof_stk_top >= 0)	    /* don't update non-existent level -1 */
 	cprof_stk[cprof_stk_top].spent_deeper += spent;
diff --git a/lib/libsys/arch/i386/spin.c b/lib/libsys/arch/i386/spin.c
index 2724f1447..e379d8bdf 100644
--- a/lib/libsys/arch/i386/spin.c
+++ b/lib/libsys/arch/i386/spin.c
@@ -61,7 +61,7 @@ int spin_check(spin_t *s)
 	case STATE_TS:
 		read_tsc_64(&cur_tsc);
 
-		tsc_delta = sub64(cur_tsc, s->s_base_tsc);
+		tsc_delta = cur_tsc - s->s_base_tsc;
 
 		micro_delta = tsc_64_to_micros(tsc_delta);
 
diff --git a/lib/libsys/arch/i386/tsc_util.c b/lib/libsys/arch/i386/tsc_util.c
index 9897efcad..c4bc19222 100644
--- a/lib/libsys/arch/i386/tsc_util.c
+++ b/lib/libsys/arch/i386/tsc_util.c
@@ -63,7 +63,7 @@ micro_delay(u32_t micros)
 	CALIBRATE;
 
 	/* We have to know when to end the delay. */
-	end = now + mul64u(micros, calib_mhz);
+	end = now + ((u64_t)micros * calib_mhz);
 
 	/* If we have to wait for at least one HZ tick, use the regular
 	 * tickdelay first. Round downwards on purpose, so the average
@@ -75,7 +75,7 @@ micro_delay(u32_t micros)
 		tickdelay(micros*Hz/MICROHZ);
 
 	/* Wait (the rest) of the delay time using busywait. */
-	while(cmp64(now, end) < 0)
+	while(now < end)
 		read_tsc_64(&now);
 
 	return OK;
@@ -87,7 +87,7 @@ u32_t tsc_64_to_micros(u64_t tsc)
 
 	CALIBRATE;
 
-	tmp = div64u64(tsc, calib_mhz);
+	tmp = tsc / calib_mhz;
 	if (ex64hi(tmp)) {
 		printf("tsc_64_to_micros: more than 2^32ms\n");
 		return ~0UL;
diff --git a/lib/libsys/sys_hz.c b/lib/libsys/sys_hz.c
index 33c9c6aad..1f2c77658 100644
--- a/lib/libsys/sys_hz.c
+++ b/lib/libsys/sys_hz.c
@@ -31,7 +31,7 @@ micros_to_ticks(u32_t micros)
 {
         u32_t ticks;
 
-        ticks = div64u(mul64u(micros, sys_hz()), 1000000);
+        ticks = (u32_t)(((u64_t)micros * sys_hz()) / 1000000);
         if(ticks < 1) ticks = 1;
 
         return ticks;
diff --git a/lib/libvboxfs/attr.c b/lib/libvboxfs/attr.c
index cef9c8a82..d6dc34d22 100644
--- a/lib/libvboxfs/attr.c
+++ b/lib/libvboxfs/attr.c
@@ -10,8 +10,8 @@ static void
 get_time(struct timespec *tsp, u64_t nsecs)
 {
 
-	tsp->tv_sec = div64u(nsecs, 1000000000);
-	tsp->tv_nsec = rem64u(nsecs, 1000000000);
+	tsp->tv_sec = (unsigned long)(nsecs / 1000000000);
+	tsp->tv_nsec = (unsigned)(nsecs % 1000000000);
 }
 
 /*
@@ -21,7 +21,7 @@ static u64_t
 set_time(struct timespec *tsp)
 {
 
-	return mul64u(tsp->tv_sec, 1000000000) + tsp->tv_nsec;
+	return ((u64_t)tsp->tv_sec * 1000000000) + tsp->tv_nsec;
 }
 
 /*
diff --git a/servers/ext2/read.c b/servers/ext2/read.c
index b4c505d38..b78ef32e8 100644
--- a/servers/ext2/read.c
+++ b/servers/ext2/read.c
@@ -175,7 +175,7 @@ int fs_breadwrite(void)
   cum_io = 0;
   /* Split the transfer into chunks that don't span two blocks. */
   while (nrbytes > 0) {
-	  off = rem64u(position, block_size);	/* offset in blk*/
+	  off = (unsigned int)(position % block_size);	/* offset in blk*/
 	  chunk = min(nrbytes, block_size - off);
 
 	  /* Read or write 'chunk' bytes. */
@@ -240,7 +240,7 @@ int *completed;                 /* number of bytes copied */
   block_spec = (rip->i_mode & I_TYPE) == I_BLOCK_SPECIAL;
 
   if (block_spec) {
-	b = div64u(position, block_size);
+	b = (unsigned long)(position / block_size);
 	dev = (dev_t) rip->i_block[0];
   } else {
 	if (ex64hi(position) != 0)
diff --git a/servers/iso9660fs/read.c b/servers/iso9660fs/read.c
index c444728fa..add98724b 100644
--- a/servers/iso9660fs/read.c
+++ b/servers/iso9660fs/read.c
@@ -107,7 +107,7 @@ int fs_bread(void)
   cum_io = 0;
   /* Split the transfer into chunks that don't span two blocks. */
   while (nrbytes != 0) {
-    off = rem64u(position, block_size);	/* offset in blk*/
+    off = (unsigned int)(position % block_size);	/* offset in blk*/
     
     chunk = MIN(nrbytes, block_size - off);
     if (chunk < 0) chunk = block_size - off;
@@ -312,20 +312,20 @@ int rw;				/* READING or PEEKING */
   if ((ex64lo(position) <= dir->d_file_size) && 
   				(ex64lo(position) > dir->data_length_l)) {
     while ((dir->d_next != NULL) && (ex64lo(position) > dir->data_length_l)) {
-      position = sub64ul(position, dir->data_length_l);
+      position -= dir->data_length_l;
       dir = dir->d_next;
     }
   }
 
   if (dir->inter_gap_size != 0) {
-    rel_block = div64u(position, block_size);
+    rel_block = (unsigned long)(position / block_size);
     file_unit = rel_block / dir->data_length_l;
     offset = rel_block % dir->file_unit_size;
     b = dir->loc_extent_l + (dir->file_unit_size +
     				 dir->inter_gap_size) * file_unit + offset;
   } else {
-    b = dir->loc_extent_l + div64u(position, block_size); /* Physical position
-							    * to read. */
+    b = dir->loc_extent_l + (unsigned long)(position / block_size); 
+    					    /* Physical position to read. */
   }
 
   bp = get_block(b);
diff --git a/servers/mfs/read.c b/servers/mfs/read.c
index c199b9803..1f818ccea 100644
--- a/servers/mfs/read.c
+++ b/servers/mfs/read.c
@@ -184,7 +184,7 @@ int fs_breadwrite(void)
   cum_io = 0;
   /* Split the transfer into chunks that don't span two blocks. */
   while (nrbytes > 0) {
-	  off = rem64u(position, block_size);	/* offset in blk*/
+	  off = (unsigned int)(position % block_size);	/* offset in blk*/
 	  chunk = min(nrbytes, block_size - off);
 
 	  /* Read or write 'chunk' bytes. */
@@ -249,7 +249,7 @@ int *completed;			/* number of bytes copied */
   block_spec = (rip->i_mode & I_TYPE) == I_BLOCK_SPECIAL;
 
   if (block_spec) {
-	b = div64u(position, block_size);
+	b = (unsigned long)(position / block_size);
 	dev = (dev_t) rip->i_zone[0];
   } else {
 	if (ex64hi(position) != 0)
diff --git a/test/test53.c b/test/test53.c
index d7d14e583..2a1b8a6f1 100644
--- a/test/test53.c
+++ b/test/test53.c
@@ -110,54 +110,68 @@ static void handler_SIGFPE(int signum)
 	exit(-1);
 }
 
+static inline int bsr64(u64_t i)
+{
+	int index;
+	u64_t mask;
+
+	for (index = 63, mask = 1ULL << 63; index >= 0; --index, mask >>= 1) {
+	    if (i & mask)
+		return index;
+	}
+
+	return -1;
+}
+
 static void testmul(void)
 {
 	int kdone, kidx;
 	u32_t ilo = ex64lo(i), jlo = ex64lo(j);
-	u64_t prod = mul64(i, j);
+	u64_t prod = i * j;
 	int prodbits;
 		
 	/* compute maximum index of highest-order bit */
 	prodbits = bsr64(i) + bsr64(j) + 1;
-	if (cmp64u(i, 0) == 0 || cmp64u(j, 0) == 0) prodbits = -1;
+	if (i == 0 || j == 0) prodbits = -1;
 	if (bsr64(prod) > prodbits) ERR;
 
 	/* compare to 32-bit multiplication if possible */	
 	if (ex64hi(i) == 0 && ex64hi(j) == 0) {
-		if (cmp64(prod, mul64u(ilo, jlo)) != 0) ERR;
+		if (prod != (u64_t)ilo * jlo) ERR;
 		
 		/* if there is no overflow we can check against pure 32-bit */
-		if (prodbits < 32 && cmp64u(prod, ilo * jlo) != 0) ERR;
+		if (prodbits < 32 && prod != ilo * jlo) ERR;
 	}
 
 	/* in 32-bit arith low-order DWORD matches regardless of overflow */
 	if (ex64lo(prod) != ilo * jlo) ERR;
 
 	/* multiplication by zero yields zero */
-	if (prodbits < 0 && cmp64u(prod, 0) != 0) ERR;
+	if (prodbits < 0 && prod != 0) ERR;
 
 	/* if there is no overflow, check absence of zero divisors */
-	if (prodbits >= 0 && prodbits < 64 && cmp64u(prod, 0) == 0) ERR;
+	if (prodbits >= 0 && prodbits < 64 && prod == 0) ERR;
 
 	/* commutativity */
-	if (cmp64(prod, mul64(j, i)) != 0) ERR;
+	if (prod != j * i) ERR;
 
 	/* loop though all argument value combinations for third argument */
 	for (kdone = 0, kidx = 0; k = getargval(kidx, &kdone), !kdone; kidx++) {
 		/* associativity */
-		if (cmp64(mul64(mul64(i, j), k), mul64(i, mul64(j, k))) != 0) ERR;
+		if ((i * j) * k != i * (j * k)) ERR;
 
 		/* left and right distributivity */
-		if (cmp64(mul64(i + j, k), mul64(i, k) + mul64(j, k)) != 0) ERR;
-		if (cmp64(mul64(i, j + k), mul64(i, j) + mul64(i, k)) != 0) ERR;
+		if ((i + j) * k != (i * k) + (j * k)) ERR;
+		if (i * (j + k) != (i * j) + (i * k)) ERR;
 	}
 }
 
 static void testdiv0(void)
 {
 	int funcidx;
+	u64_t res;
 
-	assert(cmp64u(j, 0) == 0);
+	assert(j == 0);
 
 	/* loop through the 5 different division functions */
 	for (funcidx = 0; funcidx < 5; funcidx++) {
@@ -165,11 +179,11 @@ static void testdiv0(void)
 		if (setjmp(jmpbuf_SIGFPE) == 0) {
 			/* divide by zero using various functions */
 			switch (funcidx) {
-				case 0: div64(i, j);		ERR; break;
-				case 1: div64u64(i, ex64lo(j));	ERR; break;
-				case 2: div64u(i, ex64lo(j));	ERR; break;
-				case 3: rem64(i, j);		ERR; break;
-				case 4: rem64u(i, ex64lo(j));	ERR; break;
+				case 0: res = i / j;		ERR; break;
+				case 1: res = i / ex64lo(j);	ERR; break;
+				case 2: res = i / ex64lo(j);	ERR; break;
+				case 3: res = i % j;		ERR; break;
+				case 4: res = i % ex64lo(j);	ERR; break;
 				default: assert(0);		ERR; break;
 			}
 
@@ -200,14 +214,14 @@ static void testdiv(void)
 #endif
 
 	/* division by zero has a separate test */
-	if (cmp64u(j, 0) == 0) {
+	if (j == 0) {
 		testdiv0();
 		return;
 	}
 
 	/* perform division, store q in k to make ERR more informative */
-	q = div64(i, j);
-	r = rem64(i, j);
+	q = i / j;
+	r = i % j;
 	k = q;
 
 #if TIMED
@@ -227,22 +241,22 @@ static void testdiv(void)
 
 	/* compare to 64/32-bit division if possible */
 	if (!ex64hi(j)) {
-		if (cmp64(q, div64u64(i, ex64lo(j))) != 0) ERR;
+		if (q != i / ex64lo(j)) ERR;
 		if (!ex64hi(q)) {
-			if (cmp64u(q, div64u(i, ex64lo(j))) != 0) ERR;
+			if (q != i / ex64lo(j)) ERR;
 		}
-		if (cmp64u(r, rem64u(i, ex64lo(j))) != 0) ERR;
+		if (r != i % ex64lo(j)) ERR;
 
 		/* compare to 32-bit division if possible */
 		if (!ex64hi(i)) {
-			if (cmp64u(q, ex64lo(i) / ex64lo(j)) != 0) ERR;
-			if (cmp64u(r, ex64lo(i) % ex64lo(j)) != 0) ERR;
+			if (q != ex64lo(i) / ex64lo(j)) ERR;
+			if (r != ex64lo(i) % ex64lo(j)) ERR;
 		}
 	}
 
 	/* check results using i = q j + r and r < j */
-	if (cmp64(i, mul64(q, j) + r) != 0) ERR;
-	if (cmp64(r, j) >= 0) ERR;
+	if (i != (q * j) + r) ERR;
+	if (r >= j) ERR;
 }
 
 static void test(void)
diff --git a/usr.sbin/mkfs.mfs/mkfs.c b/usr.sbin/mkfs.mfs/mkfs.c
index 8fd95c3a5..9ceb85dab 100644
--- a/usr.sbin/mkfs.mfs/mkfs.c
+++ b/usr.sbin/mkfs.mfs/mkfs.c
@@ -13,7 +13,6 @@
 #if defined(__minix)
 #include <minix/minlib.h>
 #include <minix/partition.h>
-#include <minix/u64.h>
 #include <sys/ioctl.h>
 #elif defined(__linux__)
 #include <mntent.h>
@@ -50,10 +49,6 @@
 #define BIN                  2
 #define BINGRP               2
 
-#if !defined(__minix)
-#define mul64u(a,b)	((uint64_t)(a) * (b))
-#endif
-
 /* some Minix specific types that do not conflict with Posix */
 #ifndef block_t
 typedef uint32_t block_t;	/* block number */
@@ -389,13 +384,13 @@ main(int argc, char *argv[])
 	testb = alloc_block();
 
 	/* Try writing the last block of partition or diskette. */
-	mkfs_seek(mul64u(blocks - 1, block_size), SEEK_SET);
+	mkfs_seek((uint64_t)(blocks - 1) * block_size, SEEK_SET);
 	testb[0] = 0x3245;
 	testb[1] = 0x11FF;
 	testb[block_size/2-1] = 0x1F2F;
 	w=mkfs_write(testb, block_size);
 	sync();			/* flush write, so if error next read fails */
-	mkfs_seek(mul64u(blocks - 1, block_size), SEEK_SET);
+	mkfs_seek((uint64_t)(blocks - 1) * block_size, SEEK_SET);
 	testb[0] = 0;
 	testb[1] = 0;
 	testb[block_size/2-1] = 0;
@@ -407,7 +402,7 @@ main(int argc, char *argv[])
 		    testb[0], testb[1], testb[block_size-1]);
 		errx(1, "File system is too big for minor device (read)");
 	}
-	mkfs_seek(mul64u(blocks - 1, block_size), SEEK_SET);
+	mkfs_seek((uint64_t)(blocks - 1) * block_size, SEEK_SET);
 	testb[0] = 0;
 	testb[1] = 0;
 	testb[block_size/2-1] = 0;
@@ -543,8 +538,8 @@ sizeup(char * device)
 {
   block_t d;
 #if defined(__minix)
-  u64_t bytes, resize;
-  u32_t rem;
+  uint64_t bytes, resize;
+  uint32_t rem;
 #else
   off_t size;
 #endif
@@ -562,11 +557,11 @@ sizeup(char * device)
        return 0;
   }
 
-  d = div64u(bytes, block_size);
-  rem = rem64u(bytes, block_size);
+  d = (uint32_t)(bytes / block_size);
+  rem = (uint32_t)(bytes % block_size);
 
-  resize = mul64u(d, block_size) + rem;
-  if(cmp64(resize, bytes) != 0) {
+  resize = ((uint64_t)d * block_size) + rem;
+  if(resize != bytes) {
 	/* Assume block_t is unsigned */
 	d = (block_t)(-1ul);
 	fprintf(stderr, "%s: truncating FS at %lu blocks\n",
@@ -1579,7 +1574,7 @@ get_block(block_t n, void *buf)
 	memcpy(buf, zero, block_size);
 	return;
   }
-  mkfs_seek(mul64u(n, block_size), SEEK_SET);
+  mkfs_seek((uint64_t)(n) * block_size, SEEK_SET);
   k = read(fd, buf, block_size);
   if (k != block_size)
 	pexit("get_block couldn't read block #%u", (unsigned)n);
@@ -1604,7 +1599,7 @@ put_block(block_t n, void *buf)
 
   (void) read_and_set(n);
 
-  mkfs_seek(mul64u(n, block_size), SEEK_SET);
+  mkfs_seek((uint64_t)(n) * block_size, SEEK_SET);
   mkfs_write(buf, block_size);
 }