Addressing Modes
129
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
CPUX
4.4.2.4
MSP430X Address Instructions With Indexed Mode
When using an MSP430X address instruction with indexed mode, the operand is located in memory in the
range Rn ±32KB, because the index, X, is a signed 16-bit value.
Length:
2 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:
MOVA 8002h(R5),R6 ; // R5 = 0x100
This instruction loads the 20-bit data contained in the source address into destination
register.
Source:
2 words pointed to by R5 + 8002h and R5 + 8002h + 2h which results in address 00100h
+ F8002h (+2h) = F8102h and F8104h.
Destination:
Register R6