FFFFF
0000C
Lower 64KB
0FFFF
10000
Rn.19:0
Rn.19:0
Rn.19:0
±32KB
Rn.19:0
±32KB
Addressing Modes
126
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
CPUX
Figure 4-17. Overflow and Underflow for Indexed Mode
Length:
2 or 3 words
Operation:
The sign-extended 16-bit index in the next word after the instruction is added to the
20 bits of the CPU register Rn. This delivers a 20-bit address, which points to an
address in the range 0 to FFFFFh. The operand is the content of the addressed
memory location.
Comment:
Valid for source and destination. The assembler calculates the register index and
inserts it.
Example:
ADD.W 8346h(R5),2100h(R6) ;
This instruction adds the 16-bit data contained in the source and the destination
addresses and places the 16-bit result into the destination. Source and destination
operand can be located in the entire address range.
Source:
The word pointed to by R5 + 8346h. The negative index 8346h is sign extended,
which results in address F8346h = 1B79Ch.
Destination:
The word pointed to by R6 + 2100h results in address 2100h = 17778h.