Huwebes, Agosto 15, 2013

 

How about addressing modes?

·      There are 8 addressing modes. The addressing modes determine how the operand byte is selected.

·      The direct and indirect addressing modes are used to distinguished the SPR space and data memory space

·      The relative instructions are based on the value of the program counter.

 
 
 

Instruction Set summary
 
 
 
 
 
 
 
Indexed addressing- the indexed addressing is useful when there is a need to retrieved data from a loop of table.

Immediate addressing- this mode of addressing uses either an 8 or 16 bit constant value a the source operand.

Indirect addressing- this mode uses a pointer to hold the effective address of the operand.

               -only register R0 R1 and DPTR can be used as the pointer register

Long addressing- it is a 3 bytes instructions and last 2 bytes specify a 16 bit destination location where the program branches.

Absolute addressing- two instructions associated with this mode of addressing are ACALL and JMP instructions.

 

 




 

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