indirect indexed addressing

is_razi · May 31, 2009

hi everybody,i have a problem as follow,
there is an array of data with a specific start address in a DB block,i want to read a byte from this array which the index of this byte is a byte in the same DB block and is variable.
for example consider the following DB:

address symbol type
0 index byte
1 A1 byte "base address"
2 A2 byte
3 A3 byte
4 A4 byte
5 A5 byte
6 A6 byte

now let index to be 3 ,i want to read the byte 1+3=4 which 3 is the variable index stored in the DB block and 1 is the address of the first variable in the array.
please guide me about this problem.

manmeetvirdi · May 31, 2009

Hi there
See if this helps:

Code:

OPN   DB    15            //your array DB No.
      LAR1  P#DBX 0.0     // pointing to index byte

      L     B [AR1,P#0.0] //load data of index byte
      INC   1             //increment the value by 1
      SLD   3             //shift left for byte reference
      +AR1                //increment the AR1 by index byte value+1
      L     B [AR1,P#0.0] //load data of the referred byte  
      T     MB     7      //throw it to wherever u want

indirect indexed addressing

is_razi

Member

manmeetvirdi

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