
WESTERN DESIGN CENTER
W65C816S
March 1, 2000
21
3.5.8
With this addressing mode, the 24-bit base address is pointed to by the sum of the second byte of the instruction and the
Direct Register. The effective address is this 24-bit base address plus the Y Index Register.
Direct Indirect Long Indexed-[d],y
Instruction:
OpCode
offset
Direct Register
+
offset
00
direct address
base address
then +
Operand Address:
Y Reg
effective address
3.5.9
This address mode is often referred to as Indirect,X. The second byte of the instruction is added to the sum of the
Direct Register and the X Index Register. The result points to the X low-order 16 bits of the effective address. The
Data Bank Register contains the high-order 8 bits of the effective address.
Direct Indexed Indirect-(d,x)
Instruction:
OpCode
offset
Direct Register
+
offset
direct address
+
X Reg
00
(address)
then: +
Operand Address:
DBR
effective address
3.5.10
The second byte of the instruction is added to the sum of the Direct Register and the X Index Register to form the 16-bit
effective address. The operand is always in Bank 0.
Direct Indexed With X-d,x
Instruction:
OpCode
offset
Direct Register
+
offset
direct address
+
X Reg
Operand Address:
00
effective address
3.5.11
The second byte of the instruction is added to the sum of the Direct Register and the Y Index Register to form the 16-bit
effective address. The operand is always in Bank 0.
Direct Indexed With Y-d,y
Instruction:
OpCode
offset
Direct Register
+
offset
direct address
+
Y Reg
Operand Address:
00
effective address