The CallASWI module is not a patch required for RISC OS 3.7. Rather,
it provides support under RISC OS 3.1, 3.5 and 3.6 for the following
SWIs, that are introduced in RISC OS 3.7:

              OS_CallASWI               (SWI &6F)
              OS_CallASWIR12            (SWI &71)
              OS_PlatformFeatures       (SWI &6D)
              OS_SynchroniseCodeAreas   (SWI &6E)

This will enable application programmers and library writers to use the
new calls freely without any worries about backwards compatibility. There
is no performance penalty for the use of these SWIs via the CallASWI
module. One slight caveat is that older machines will not know the
_names_ of these SWIs; they will have to be called by number from BASIC.

In using the CallASWI module, an application !Run file should ensure the
module with a line of the form:

RMEnsure UtilityModule 3.70 RMEnsure CallASWI 0.01 RMLoad System:Modules.CallASWI

This module may be freely distributed with any applications designed
for use with any version of RISC OS between 3.10 and 3.60 running on
Acorn RISC OS computers, subject to _all_ of the conditions below.

After installation of the application, this module must not reside
within that application; it must reside in !System.

This module is provided "as is"; Acorn Computers Limited ("Acorn")
makes no warranty, express or implied, of the merchantability of this
software or its fitness for any particular purpose. In no circumstances
shall Acorn be liable for any damage, loss of profits, or any indirect or
consequential loss arising out of the use of this software or inability to
use this software, even if Acorn has been advised of the possibility of
such loss.