Motorola HC12 사용자 설명서

다운로드
페이지 328
User’s Manual
MCUez HC12 Assembler
134
Assembler Syntax
MOTOROLA
Assembler Syntax
7.4.3.6  Indexed, 5-Bit Offset
This addressing mode adds a 5-bit signed offset to the base index register to
form the memory address, which is referenced in the instruction. The valid
range for a 5-bit signed offset is [–16...15]. The base index register may be X,
Y, SP, PC, or PCR.
For information about indexed PC and indexed PC relative addressing modes,
see
This addressing mode may be used to access elements in an n-element table,
whose size is smaller than 16 bytes.
Example:
           ORG $1000
CST_TBL:    DC.B $5, $10, $18, $20, $28, $30
            ORG $800
DATA_TBL:   DS.B 10
main:
            LDX #$CST_TBL
            LDAA 3,X
            LDY #DATA_TBL
            STAA 8, Y
Accumulator A is loaded with the byte value stored in memory location $1003
($1000 +3).
Then the value of accumulator A is stored at address $808 ($800 +8).