Editing Orthogonal instruction set (section)

===The MC68000 and similar===
Motorola's designers attempted to make the assembly language orthogonal while the underlying machine language was somewhat less so. Unlike PDP-11, the MC68000 (68k) used separate registers to store data and the addresses of data in memory. The ISA was orthogonal to the extent that addresses could only be used in those registers, but there was no restriction on ''which'' of the registers could be used by different instructions. Likewise, the data registers were also orthogonal across instructions. Unlike the PDP-11, the 68000 only supported one general addressing mode for two-parameter instructions. The other parameter was always a register, with the exception of MOV. The MOV instructions supported all addressing modes for both parameters.<ref name=68k>{{cite book |title= The 68000 Microprocessor |first= Andrew |last=Veronis |page=54 |url=https://books.google.com/books?id=O2DTBwAAQBAJ&pg=PA54|isbn= 9781468466478 |date= 2012-12-06 |publisher= Springer }}</ref>

In contrast, the [[NS320xx]] series were originally designed as single-chip implementations of the VAX-11 ISA. Although this had to change due to legal issues, the resulting system retained much of the VAX-11's overall design philosophy and remained completely orthogonal.<ref name="tilson198310">{{cite news | url=https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n267/mode/2up | title=Moving Unix to New Machines | work=BYTE | date=October 1983 | access-date=31 January 2015 | author=Tilson, Michael | pages=266}}</ref> This included the elimination of the separate data and address registers found in the 68k.<ref>{{cite web |url=http://www.datormuseum.se/home/chips/ns32532 |title= NS32532 |website=Datormuseum}}</ref>