doc: buffers: section on arithmetic conventions.

* txr.1: Add Arithmetic Conventions of Buffer section.

1 files changed, 22 insertions, 0 deletions

diff --git a/txr.1 b/txr.1
index 48c37097..10d77642 100644
--- a/txr.1
+++ b/txr.1
@@ -28943,6 +28943,28 @@ The
 function returns a value of type
 .codn cptr .
 
+.NP Arithmetic Conventions of Buffers
+
+Buffers support a limited number of functions for dealing
+with buffers as if they were integers. Buffers may be
+converted to and from integer values using the functions
+.codn buf-int ,
+.codn buf-uint ,
+.code int-buf
+and
+.codn uint-buf .
+A number of bitwise manipulation functions are provided
+such as
+.codn buf-ash ,
+.codn buf-and ,
+.code buf-or
+and others.
+
+Under arithmetic, buffers are regarded as binary numbers in big-endian
+representation, whereby the last byte of a buffer
+represents the least significant eight bits of the integer.
+An empty buffer is taken to be zero.
+
 .NP* Fill Pattern Argument Conventions
 
 Several buffer functions accept a fill pattern argument,