Chapter 9 XGATE (S12XGATEV2)
MC9S12XDP512 Data Sheet, Rev. 2.11
400 Freescale Semiconductor
9.8.1.1 Naming Conventions
RD Destination register, allowed range is R0–R7
RD.L Low byte of the destination register, bits [7:0]
RD.H High byte of the destination register, bits [15:8]
RS, RS1, RS2 Source register, allowed range is R0–R7
RS.L, RS1.L, RS2.L Low byte of the source register, bits [7:0]
RS.H, RS1.H, RS2.H High byte of the source register, bits[15:8]
RB Base register for indexed addressing modes, allowed
range is R0–R7
RI Offset register for indexed addressing modes with
register offset, allowed range is R0–R7
RI+ Offset register for indexed addressing modes with
register offset and post-increment,
Allowed range is R0–R7 (R0+ is equivalent to R0)
–RI Offset register for indexed addressing modes with
register offset and pre-decrement,
Allowed range is R0–R7 (–R0 is equivalent to R0)
NOTE
Even though register R1 is intended to be used as a pointer to the variable
segment, it may be used as a general purpose data register as well.
Selecting R0 as destination register will discard the result of the instruction.
Only the condition code register will be updated
9.8.1.2 Inherent Addressing Mode (INH)
Instructions that use this addressing mode either have no operands or all operands are in internal XGATE
registers:.
Examples
BRK
RTS
9.8.1.3 Immediate 3-Bit Wide (IMM3)
Operands for immediate mode instructions are included in the instruction stream and are fetched into the
instruction queue along with the rest of the 16 Bit instruction. The ’#’ symbol is used to indicate an
immediate addressing mode operand. This address mode is used for semaphore instructions.
Examples:
CSEM #1 ; Unlock semaphore 1
SSEM #3 ; Lock Semaphore 3