1 files changed, 55 insertions, 0 deletions
diff --git a/docs/src/wiki-deprecated/interval-type.md b/docs/src/wiki-deprecated/interval-type.md
new file mode 100644
index 00000000..7f33461e
--- /dev/null
+++ b/docs/src/wiki-deprecated/interval-type.md
@@ -0,0 +1,55 @@
+# Intervals
+**Intervals** are a new experimental numeric type that comprises UInt, SInt and FixedPoint numbers.
+It augments these types with range information, i.e. upper and lower numeric bounds.
+This information can be used to exercise tighter programmatic control over the ultimate widths of
+signals in the final circuit.  The **Firrtl** compiler can infer this range information based on 
+operations and earlier values in the circuit. Intervals support all the ordinary bit and arithmetic operations
+associated with UInt, SInt, and FixedPoint and adds the following methods for manipulating the range of
+a **source** Interval with the IntervalRange of **target** Interval 
+
+### Clip -- Fit the value **source** into the IntervalRange of **target**, saturate if out of bounds
+The clip method applied to an interval creates a new interval based on the argument to clip,
+and constructs the necessary hardware so that the source Interval's value will be mapped into the new Interval.
+Values that are outside the result range will be pegged to either maximum or minimum of result range as appropriate.
+
+> Generates necessary hardware to clip values, values greater than range are set to range.high, values lower than range are set to range min.
+
+### Wrap -- Fit the value **source** into the IntervalRange of **target**, wrapping around if out of bounds
+The wrap method applied to an interval creates a new interval based on the argument to wrap,
+and constructs the necessary
+hardware so that the source Interval's value will be mapped into the new Interval.
+Values that are outside the result range will be wrapped until they fall within the result range.
+
+> Generates necessary hardware to wrap values, values greater than range are set to range.high, values lower than range are set to range min.
+
+> Does not handle out of range values that are less than half the minimum or greater than twice maximum
+
+### Squeeze -- Fit the value **source** into the smallest IntervalRange based on source and target.
+The squeeze method applied to an interval creates a new interval based on the argument to clip, the two ranges must overlap
+behavior of squeeze with inputs outside of the produced range is undefined.
+
+> Generates no hardware, strictly a sizing operation
+
+#### Range combinations
+
+| Condition | A.clip(B) | A.wrap(B) | A.squeeze(B) |
+| --------- | --------------- | --------------- | --------------- |
+| A === B   | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  |
+| A contains B   | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  |
+| B contains A   | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  |
+| A min < B min, A max in B  | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  |
+| A min in B, A max > B max  | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  | max(Alo, Blo), min(Ahi, Bhi)  |
+| A strictly less than B   | error               | error               | error               |
+| A strictly greater than B   | error               | error               | error               |
+
+
+### Applying binary point operators to an Interval
+
+Consider a Interval with a binary point of 3: aaa.bbb 
+
+| operation | after operation | binary point | lower | upper | meaning | 
+| --------- | --------------- | ------------ | ----- | ----- | ------- |
+| setBinaryPoint(2) | aaa.bb |  2 | X | X  | set the precision |
+| shiftLeftBinaryPoint(2) | a.aabbb |  5 | X | X  | increase the precision |
+| shiftRighBinaryPoint(2) | aaaa.b |  1 | X | X  | reduce the precision |
+