w65c816s Western Design Center, Inc., w65c816s Datasheet - Page 21

• Manufacturer Part Number: w65c816s
• Description: W65c816s 8/16?bit Microprocessor
• Manufacturer: Western Design Center, Inc.

3.5.11 Direct Indexed with X-d,x
With Direct Indexed with X (d,x) addressing 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.
3.5.12 Direct Indexed with Y-d,y
With Direct Indexed with Y (d,y) addressing 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.
3.5.13 Direct Indirect Indexed-(d),y
Direct Indirect Indexed ((d),y) addressing is often referred to as Indirect Y addressing. The second byte
of the instruction is added to the Direct Register (D). The 16-bit content of this memory location is then
combined with the Data Bank register to form a 24-bit base address. The Y Index Register is added to
the base address to form the effective address.
then:
Instruction:
Operand
Address:
+
+
Instruction:
Instruction:
Operand
Address:
Operand
Address:
Opcode
DBR
00
+
effective address
base address
offset
Opcode
Opcode
(direct address)
Direct Register
00
00
+
+
+
+
Y Reg
offset
offset
offset
effective address
effective address
Direct Register
Direct Register
direct address
direct address
X Reg
Y Reg
offset
offset
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