|Alto_II_Microcode_Aug75.pdf||Inter-Office l\'Temorand urn
To Alto Users Date 19 August 1975
From C. Thacker location Palo Alto
Subject Alto II Microcode Organization CSL
This memo is a description of the changes which have been made in the standard
Alto microcode for the second build. These changes will not affect the operation of
the present software (except to make it work better in some cases), but they will
make it possible to run Lisp, and make certain const.ructs simpler for those who wish
to wri te special purpose microcode.
The changes are:
1) A bug which sometimes caused a 1\1:44 disk to get spurious da ta late errors when
the processor executed the BLT or BLKS instruction has been fixed.
2) The constant memory has been expanded.
3) Unused opcodes 61022-61037, which if executed would produce bizarre results, now
4) A bug which caused unused parameterless opcodes in|