Added rationale for choice of divide overflow results.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/m.tex b/src/m.tex
index cc289e8..347d85d 100644
--- a/src/m.tex
+++ b/src/m.tex
@@ -136,4 +136,12 @@ branch instruction needs to be added to each divide operation, and
 this branch instruction can be inserted after the divide and should
 normally be very predictably not taken, adding little runtime
 overhead.
+
+The value of all bits set is returned for both unsigned and signed
+divide by zero to simplify the divider circuitry.  The value of all 1s
+is both the natural value to return for unsigned divide, representing
+the largest unsigned number, and also the natural result for simple
+unsigned divider implementations.  Signed division is often
+implemented using an unsigned division circuit and specifying the same
+overflow result simplifies the hardware.
 \end{commentary}