Toshiba T2N - Manual (Page 196)

3.User Data
User's manual 183
When registers are used by instructions, the method of directly
designating the register address as shown in Example 1) below is called
‘direct addressing’.
As opposed to this, the method of indirectly designating the register by
combination with the contents of the index registers (I, J, K) as shown in
Example 2) below is called the ‘indirect addressing’. In particular, in this
case, since the address is modified using an index register, this is called
‘index modification’.
Example 1)
–[ RW100 MOV D3500 ]–
Data transfer instruction
Transfer content of RW100 to D3500
Example 2)
I J
–[ RW100 MVO D3500 ]–
Data transfer instruction (index modification attached)
Transfer content of RW(100 + I) to D(3500 + J)
(If I =3 and J = 200, the content of RW103 is transferred to D3700)
There are 3 types of index register - I, J and K. Each type processes 16-
bit integers (-32768 to 32767). There are no particular differences in
function between these 3 types of index register.
There is no special instruction for substituting values in these index
registers. These are designated as normal transfer instructions or as
destination for operation instructions.
Example 1) Substituting a constant in an index register
–[ 64 MOV I ]– (Substitute 64 in index register I)
–[ - 2 MOV J ]]– (Substitute -2 in index register J)
Example 2) Substituting register data in an index register
–[ D0035 MOV K ]– (Substitute the value of D0035 in index register K)
–[ RW078 MOV I ]– (Substitute the value of RW078 in index
register I)
3.4
Index Modification