Byte order

The byte order within a longword or word according to the transputer is opposite to the order defined by VME. This means that reading byte 0, byte 1, byte 2 and byte 3 by the transputer from VME delivers respectively byte 3, byte 2, byte 1 and byte 0 according to VME; the same is true for the word order within a longword :

• VME 32-bits transfer :
  

  

• VME 8-bits/16-bits transfer :
  

  

Example: if a byte value has to be written to VME-address $1001 in OCCAM it can be declared and 'PLACE'd as follows :

  [4]BYTE bytes :
  PLACE bytes AT ((#1000 >< MOSTNEG INT) >> 2) :
  -- To access byte 1 in VME access byte 2 on the transputer
  byte.address.1001 IS bytes[2] :