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Chapter 10 XGATE (S12XGATEV3)
MC9S12XE-Family Reference Manual , Rev. 1.07
390
Freescale Semiconductor
10.8.1.8
Dyadic Addressing (DYA)
In this mode the result of an operation between two registers is stored in one of the registers used as
operands.
RD = RD
RS is the general register to register format, with register RD being the first operand and RS
the second. RD and RS can be any of the 8 general purpose registers R0 … R7. If R0 is used as the
destination register, only the condition code flags are updated. This addressing mode is used only for shift
operations with a variable shift value
Examples:
LSL
LSR
R4,R5
R4,R5
; R4 = R4 << R5
; R4 = R4 >> R5
10.8.1.9
Triadic Addressing (TRI)
In this mode the result of an operation between two or three registers is stored into a third one.
RD = RS1
RS2 is the general format used in the order RD, RS1, RS1. RD, RS1, RS2 can be any of the
8 general purpose registers R0 … R7. If R0 is used as the destination register RD, only the condition code
flags are updated. This addressing mode is used for all arithmetic and logical operations.
Examples:
ADC
SUB
R5,R6,R7
R5,R6,R7
; R5 = R6 + R7 + Carry
; R5 = R6 - R7
10.8.1.10 Relative Addressing 9-Bit Wide (REL9)
A 9-bit signed word address offset is included in the instruction word. This addressing mode is used for
conditional branch instructions.
Examples:
BCC
BEQ
REL9
REL9
; PC = PC + 2 + (REL9 << 1)
; PC = PC + 2 + (REL9 << 1)
10.8.1.11 Relative Addressing 10-Bit Wide (REL10)
An 10-bit signed word address offset is included in the instruction word. This addressing mode is used for
the unconditional branch instruction.
Examples:
BRA
REL10
; PC = PC + 2 + (REL10 << 1)
10.8.1.12 Index Register plus Immediate Offset (IDO5)
(RS, #OFFS5) provides an unsigned offset from the base register.
Examples:
LDB
STW
R4,(R1,#OFFS5)
R4,(R1,#OFFS5)
; loads a byte from (R1+OFFS5) into R4
; stores R4 as a word to (R1+OFFS5)