Motorola HC12 - Manual (Page 142)

User’s Manual MCUez HC12 Assembler
142 Assembler Syntax MOTOROLA
Assembler Syntax
7.4.3.14 Indexed, Accumulator Offset
This addressing mode adds the value in the specified accumulator to the base
index register to form the address, which is referenced in the instruction. The
base index register may be X, Y, SP, or PC. The accumulator may be A, B, or D.
Example:
main:
LDAB #$20
LDX #$600
LDAA B,X
LDY #$1000
STAA $140, Y
The value stored in B ($20) is added to the value of X ($600) to form a memory
address ($620). The value stored at $620 is loaded in accumulator A.