6740h
Address Space
4766h
50D0h
PC
21038h
21036h
21034h
21038h
+56740h
77778h
Before:
Address Space
After:
PC
xxxxh
xx45h
7777Ah
77778h
xxxxh
xx77h
7777Ah
77778h
32h
+45h
77h
src
dst
Sum
xxxxh
xx32h
3579Eh
3579Ch
xxxxh
xx32h
3579Eh
3579Ch
18C5h
21032h
xxxxh
2103Ah
6740h
4766h
50D0h
21038h
21036h
21034h
18C5h
21032h
xxxxh
2103Ah
21036h
+14766h
3579Ch
Addressing Modes
134
SLAU367P – October 2012 – Revised April 2020
Copyright © 2012–2020, Texas Instruments Incorporated
CPUX
4.4.3.3
MSP430X Instruction With Symbolic Mode
When using an MSP430X instruction with symbolic mode, the operand can be located anywhere in the
range of PC + 19 bits.
Length:
3 or 4 words
Operation:
The operand address is the sum of the 20-bit PC and the 20-bit index. The 4 MSBs
of the index are contained in the extension word; the 16 LSBs are contained in the
word following the instruction.
Comment:
Valid for source and destination. The assembler calculates the register index and
inserts it.
Example:
ADDX.B EDE,TONI ;
This instruction adds the 8-bit data contained in source byte EDE and destination
byte TONI and places the result into the destination byte TONI.
Source:
Byte EDE located at address 3579Ch, pointed to by PC + 14766h, is the 20-bit
result of 3579Ch – 21036h = 14766h. Address 21036h is the address of the index
in this example.
Destination:
Byte TONI located at address 77778h, pointed to by PC + 56740h, is the 20-bit
result of 77778h – 21038h = 56740h. Address 21038h is the address of the index in
this example.