diff --git a/runtime/src/jet/ByteRange.java b/runtime/src/jet/ByteRange.java
index 6d260a78484..3c391baba41 100644
--- a/runtime/src/jet/ByteRange.java
+++ b/runtime/src/jet/ByteRange.java
@@ -81,9 +81,9 @@ public final class ByteRange implements Range<Byte>, ByteIterable {
 
     public ByteIterator step(int step) {
         if (step < 0)
-            return new ByteIteratorImpl(getEnd(), -count, -step);
+            return new ByteIteratorImpl(getEnd(), getStart(), step);
         else
-            return new ByteIteratorImpl(start, count, step);
+            return new ByteIteratorImpl(getStart(), getEnd(), step);
     }
 
     public byte getStart() {
@@ -100,46 +100,30 @@ public final class ByteRange implements Range<Byte>, ByteIterable {
 
     @Override
     public ByteIterator iterator() {
-        return new ByteIteratorImpl(start, count, 1);
+        return new ByteIteratorImpl(getStart(), getEnd(), 1);
     }
 
     private static class ByteIteratorImpl extends ByteIterator {
-        private final int step;
-        private byte cur;
-        private int count;
+        private byte next;
+        private final byte end;
+        private final int increment;
 
-        private final boolean reversed;
-
-        public ByteIteratorImpl(byte startValue, int count, int step) {
-            cur = startValue;
-            this.step = step;
-            if (count < 0) {
-                reversed = true;
-                count = -count;
-                startValue += count;
-            }
-            else {
-                reversed = false;
-            }
-            this.count = count;
+        public ByteIteratorImpl(byte start, byte end, int increment) {
+            this.next = start;
+            this.end = end;
+            this.increment = increment;
         }
 
         @Override
         public boolean hasNext() {
-            return count > 0;
+            return increment > 0 ? next <= end : next >= end;
         }
 
         @Override
         public byte nextByte() {
-            count -= step;
-            if (reversed) {
-                cur -= step;
-                return (byte) (cur + step);
-            }
-            else {
-                cur += step;
-                return (byte) (cur - step);
-            }
+            byte value = next;
+            next += increment;
+            return value;
         }
     }
 }
diff --git a/runtime/src/jet/CharRange.java b/runtime/src/jet/CharRange.java
index 5f375bb52e0..bae494ca70e 100644
--- a/runtime/src/jet/CharRange.java
+++ b/runtime/src/jet/CharRange.java
@@ -81,9 +81,9 @@ public final class CharRange implements Range<Character>, CharIterable {
 
     public CharIterator step(int step) {
         if (step < 0)
-            return new CharIteratorImpl(getEnd(), -count, -step);
+            return new CharIteratorImpl(getEnd(), getStart(), step);
         else
-            return new CharIteratorImpl(start, count, step);
+            return new CharIteratorImpl(getStart(), getEnd(), step);
     }
 
     public char getStart() {
@@ -100,46 +100,30 @@ public final class CharRange implements Range<Character>, CharIterable {
 
     @Override
     public CharIterator iterator() {
-        return new CharIteratorImpl(start, count, 1);
+        return new CharIteratorImpl(getStart(), getEnd(), 1);
     }
 
     private static class CharIteratorImpl extends CharIterator {
-        private final int step;
-        private char cur;
-        private int count;
+        private char next;
+        private final char end;
+        private final int increment;
 
-        private final boolean reversed;
-
-        public CharIteratorImpl(char startValue, int count, int step) {
-            cur = startValue;
-            this.step = step;
-            if (count < 0) {
-                reversed = true;
-                count = -count;
-                startValue += count;
-            }
-            else {
-                reversed = false;
-            }
-            this.count = count;
+        public CharIteratorImpl(char start, char end, int increment) {
+            this.next = start;
+            this.end = end;
+            this.increment = increment;
         }
 
         @Override
         public boolean hasNext() {
-            return count > 0;
+            return increment > 0 ? next <= end : next >= end;
         }
 
         @Override
         public char nextChar() {
-            count -= step;
-            if (reversed) {
-                cur -= step;
-                return (char) (cur + step);
-            }
-            else {
-                cur += step;
-                return (char) (cur - step);
-            }
+            char value = next;
+            next += increment;
+            return value;
         }
     }
 }
diff --git a/runtime/src/jet/DoubleRange.java b/runtime/src/jet/DoubleRange.java
index d56b774ce89..08f14c5c7b8 100644
--- a/runtime/src/jet/DoubleRange.java
+++ b/runtime/src/jet/DoubleRange.java
@@ -79,9 +79,9 @@ public final class DoubleRange implements Range<Double> {
 
     public DoubleIterator step(double step) {
         if (step < 0)
-            return new DoubleIteratorImpl(getEnd(), -size, -step);
+            return new DoubleIteratorImpl(getEnd(), getStart(), step);
         else
-            return new DoubleIteratorImpl(start, size, step);
+            return new DoubleIteratorImpl(getStart(), getEnd(), step);
     }
 
     public double  getStart() {
@@ -97,44 +97,26 @@ public final class DoubleRange implements Range<Double> {
     }
 
     private static class DoubleIteratorImpl extends DoubleIterator {
-        private final double step;
+        private double next;
         private final double end;
-        private double cur;
+        private final double increment;
 
-        private final boolean reversed;
-
-        public DoubleIteratorImpl(double startValue, double size, double step) {
-            cur = startValue;
-            this.step = step;
-            if (size < 0) {
-                reversed = true;
-                end = startValue-size;
-                startValue -= size;
-            }
-            else {
-                reversed = false;
-                this.end = startValue + size;
-            }
+        public DoubleIteratorImpl(double start, double end, double increment) {
+            this.next = start;
+            this.end = end;
+            this.increment = increment;
         }
 
         @Override
         public boolean hasNext() {
-            if (reversed)
-                return cur >= end;
-            else
-                return cur <= end;
+            return increment > 0 ? next <= end : next >= end;
         }
 
         @Override
         public double nextDouble() {
-            if (reversed) {
-                cur -= step;
-                return cur + step;
-            }
-            else {
-                cur += step;
-                return cur - step;
-            }
+            double value = next;
+            next += increment;
+            return value;
         }
     }
 }
diff --git a/runtime/src/jet/FloatRange.java b/runtime/src/jet/FloatRange.java
index 03603d87471..20ffd722c33 100644
--- a/runtime/src/jet/FloatRange.java
+++ b/runtime/src/jet/FloatRange.java
@@ -75,9 +75,9 @@ public final class FloatRange implements Range<Float> {
 
     public FloatIterator step(float step) {
         if (step < 0)
-            return new FloatIteratorImpl(getEnd(), -size, -step);
+            return new FloatIteratorImpl(getEnd(), getStart(), step);
         else
-            return new FloatIteratorImpl(start, size, step);
+            return new FloatIteratorImpl(getStart(), getEnd(), step);
     }
 
     public float  getStart() {
@@ -93,44 +93,26 @@ public final class FloatRange implements Range<Float> {
     }
 
     private static class FloatIteratorImpl extends FloatIterator {
-        private final float step;
+        private float next;
         private final float end;
-        private float cur;
+        private final float increment;
 
-        private final boolean reversed;
-
-        public FloatIteratorImpl(float startValue, float size, float step) {
-            cur = startValue;
-            this.step = step;
-            if (size < 0) {
-                reversed = true;
-                end = startValue-size;
-                startValue -= size;
-            }
-            else {
-                reversed = false;
-                this.end = startValue + size;
-            }
+        public FloatIteratorImpl(float start, float end, float increment) {
+            this.next = start;
+            this.end = end;
+            this.increment = increment;
         }
 
         @Override
         public boolean hasNext() {
-            if (reversed)
-                return cur >= end;
-            else
-                return cur <= end;
+            return increment > 0 ? next <= end : next >= end;
         }
 
         @Override
         public float nextFloat() {
-            if (reversed) {
-                cur -= step;
-                return cur + step;
-            }
-            else {
-                cur += step;
-                return cur - step;
-            }
+            float value = next;
+            next += increment;
+            return value;
         }
     }
 }
diff --git a/runtime/src/jet/IntRange.java b/runtime/src/jet/IntRange.java
index 5e187542490..d426faac162 100644
--- a/runtime/src/jet/IntRange.java
+++ b/runtime/src/jet/IntRange.java
@@ -81,9 +81,9 @@ public final class IntRange implements Range<Integer>, IntIterable {
 
     public IntIterator step(int step) {
         if (step < 0)
-            return new IntIteratorImpl(getEnd(), -count, -step);
+            return new IntIteratorImpl(getEnd(), getStart(), step);
         else
-            return new IntIteratorImpl(start, count, step);
+            return new IntIteratorImpl(getStart(), getEnd(), step);
     }
 
     public int getStart() {
@@ -100,46 +100,30 @@ public final class IntRange implements Range<Integer>, IntIterable {
 
     @Override
     public IntIterator iterator() {
-        return new IntIteratorImpl(start, count, 1);
+        return new IntIteratorImpl(getStart(), getEnd(), 1);
     }
 
     private static class IntIteratorImpl extends IntIterator {
-        private int cur;
-        private int step;
-        private int count;
+        private int next;
+        private final int end;
+        private final int increment;
 
-        private final boolean reversed;
-
-        public IntIteratorImpl(int startValue, int count, int step) {
-            cur = startValue;
-            this.step = step;
-            if (count < 0) {
-                reversed = true;
-                count = -count;
-                startValue += count;
-            }
-            else {
-                reversed = false;
-            }
-            this.count = count;
+        public IntIteratorImpl(int start, int end, int increment) {
+            this.next = start;
+            this.end = end;
+            this.increment = increment;
         }
 
         @Override
         public boolean hasNext() {
-            return count > 0;
+            return increment > 0 ? next <= end : next >= end;
         }
 
         @Override
         public int nextInt() {
-            count -= step;
-            if (reversed) {
-                cur -= step;
-                return cur + step;
-            }
-            else {
-                cur += step;
-                return cur - step;
-            }
+            int value = next;
+            next += increment;
+            return value;
         }
     }
 }
diff --git a/runtime/src/jet/LongRange.java b/runtime/src/jet/LongRange.java
index 368d5a94874..fa100fa3e84 100644
--- a/runtime/src/jet/LongRange.java
+++ b/runtime/src/jet/LongRange.java
@@ -82,9 +82,9 @@ public final class LongRange implements Range<Long>, LongIterable {
 
     public LongIterator step(long step) {
         if (step < 0)
-            return new LongIteratorImpl(getEnd(), -count, -step);
+            return new LongIteratorImpl(getEnd(), getStart(), step);
         else
-            return new LongIteratorImpl(start, count, step);
+            return new LongIteratorImpl(getStart(), getEnd(), step);
     }
 
     public long getStart() {
@@ -101,46 +101,30 @@ public final class LongRange implements Range<Long>, LongIterable {
 
     @Override
     public LongIterator iterator() {
-        return new LongIteratorImpl(start, count, 1);
+        return new LongIteratorImpl(getStart(), getEnd(), 1);
     }
 
     private static class LongIteratorImpl extends LongIterator {
-        private final long step;
-        private long cur;
-        private long count;
+        private long next;
+        private final long end;
+        private final long increment;
 
-        private final boolean reversed;
-
-        public LongIteratorImpl(long startValue, long count, long step) {
-            cur = startValue;
-            this.step = step;
-            if (count < 0) {
-                reversed = true;
-                count = -count;
-                startValue += count;
-            }
-            else {
-                reversed = false;
-            }
-            this.count = count;
+        public LongIteratorImpl(long start, long end, long increment) {
+            this.next = start;
+            this.end = end;
+            this.increment = increment;
         }
 
         @Override
         public boolean hasNext() {
-            return count > 0;
+            return increment > 0 ? next <= end : next >= end;
         }
 
         @Override
         public long nextLong() {
-            count -= step;
-            if (reversed) {
-                cur -= step;
-                return (cur + step);
-            }
-            else {
-                cur += step;
-                return (cur - step);
-            }
+            long value = next;
+            next += increment;
+            return value;
         }
     }
 }
diff --git a/runtime/src/jet/ShortRange.java b/runtime/src/jet/ShortRange.java
index ac5650f854e..8153fd3e655 100644
--- a/runtime/src/jet/ShortRange.java
+++ b/runtime/src/jet/ShortRange.java
@@ -81,9 +81,9 @@ public final class ShortRange implements Range<Short>, ShortIterable {
 
     public ShortIterator step(int step) {
         if (step < 0)
-            return new ShortIteratorImpl(getEnd(), -count, -step);
+            return new ShortIteratorImpl(getEnd(), getStart(), step);
         else
-            return new ShortIteratorImpl(start, count, step);
+            return new ShortIteratorImpl(getStart(), getEnd(), step);
     }
 
     public short getStart() {
@@ -100,46 +100,30 @@ public final class ShortRange implements Range<Short>, ShortIterable {
 
     @Override
     public ShortIterator iterator() {
-        return new ShortIteratorImpl(start, count, 1);
+        return new ShortIteratorImpl(getStart(), getEnd(), 1);
     }
 
     private static class ShortIteratorImpl extends ShortIterator {
-        private final int step;
-        private short cur;
-        private int count;
+        private short next;
+        private final short end;
+        private final int increment;
 
-        private final boolean reversed;
-
-        public ShortIteratorImpl(short startValue, int count, int step) {
-            cur = startValue;
-            this.step = step;
-            if (count < 0) {
-                reversed = true;
-                count = -count;
-                startValue += count;
-            }
-            else {
-                reversed = false;
-            }
-            this.count = count;
+        public ShortIteratorImpl(short start, short end, int increment) {
+            this.next = start;
+            this.end = end;
+            this.increment = increment;
         }
 
         @Override
         public boolean hasNext() {
-            return count > 0;
+            return increment > 0 ? next <= end : next >= end;
         }
 
         @Override
         public short nextShort() {
-            count -= step;
-            if (reversed) {
-                cur -= step;
-                return (short) (cur + step);
-            }
-            else {
-                cur += step;
-                return (short) (cur - step);
-            }
+            short value = next;
+            next += increment;
+            return value;
         }
     }
 }