W65C832_1 Datasheet, PDF (28/64 Pages) –

WDC
THE WESTERN DESIGN CENTER, INC.
W65C832
3.5.20 Absolute Indexed Indirect-(a,x)
The second and third bytes of the instruction are added to the X Index
Register to form a 16-::bit pointer in Bank O. The contents of this
pointer are loaded in the Program Counter. The Program Bank Register is
not changed.
Instruction: opcode addrl I addrh
addrh I addrl
I X Reg
PBR
address
then:
PC = (address)
3.5.21 Stack-s
Stack addressing refers to all instructions that push or pull data from
the stack, such as Push, Pull, Jump to Subroutine, Return from
Subroutine, Interrupts, and Return from Interrupt. The bank address is
always O. Interrupt Vectors are always fetched from Bank O.
3.5.22 Stack Relative-d,s
The low-order 16 bits of the effective address is formed from the sum of
the second byte of the instruction and the stack pointer. The
high-order 8 bits of the effective address is always zero. The relative
offset is an unsigned 8-bit quantity in the range of 0 to 255.
Instruction: opcode I offset I
I Stack Pointer
Operand
+
I offset I
Address:
I 00 leffective address I
* 3.5.23 Stack Relative Indirect Indexed-(d,s),y
The second byte of the instruction is added to the Stack Pointer to form
a pointer to the low-order 16-bit base address in Bank O. The Data Bank
Register contains the high-order 8 bits of the base address. The
effective address is the sum of the 24-bit base address and the Y Index
Register. In the native mode this creates 32-bit effective addresses.
Instruction: opcode I offset I
1 Stack Pointer
+
I offset
00 I S + offset
then:
I S + offset
+1 DBR I
I
base address
Operand
+
I
I Y Reg
Address:
I effective address
MARCH 1990
20