6F3B0253
6. Programming Information
6.2 Index modification
When registers are used as operands of 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 register (I, J, or K) as shown in Example 2) below is called ‘indirect addressing’. In particular, in this case, since the address is modified using an index register, this is called ‘index modification’.
Example 1)
[ RW10 MOV D1000 ]
Data transfer instruction
Transfer data of RW10 to D1000
Example 2)
IJ
[ RW10 MOV D0000 ]
Data transfer instruction (with index modification) Transfer data of RW(10 + I) to D(0000 + J)
(If I = 3 and J = 200, the data of RW13 is transferred to D0200)
There are 3 types of index register, I, J and K. Each type processes
There is no special instruction for substituting values in these index registers. These are designated as destination of data transfer instructions, etc.
| [ 00064 | MOV | I ] | (substitutes 64 in index register I) |
| [ D0035 | MOV | J ] | (substitutes the data of D0035 in index register J) |
| [ RW20 | + 00030 → | K ] (substitutes the result of addition in index register K) | |
NOTE
(1)The index modification is available for RW, T, C and D registers.
(2)If index registers are used as a
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