1989_MELPS_7700_Software_Manual

Direct Indexed Y
Mode
Function
Direct indexed V addressing mode
The contents of the bank-O memory location specified by the result of adding the second
byte of the instruction, the contents of the direct page register and the contents
of the index register V become the actual data. If, however, addition of the instruc- I
tion's second byte, the direct page register's contents and the index register V's
contents results in a value that exceeds the bank-O or bank-1 range, the specified'
location will be in bank-1 or bank-2.
Instruction: LOX, STX
ex.
: Mnemonic
LOX 02H,Y
(x = 1)
Machine Code
86 16 02 16
Memory
DATA
0000,.
Bank-O
131C,. ~-------,
-------
F
......
Op Code (B6,.)
Operand (02,.)
FFFF,.
Drrect Page Index
Register Register Y
+1 1234,. I+~ = 131C,.
ex.
: Mnemonic
LOX 02H,Y
(x=O)
Machine Code
86 16 02 16
x ..... 1 DATAH ! DATAL 1- {
Memory
DATAL
DATAH
DODO,.
Bank-O
131C, •."...------,
------- FFFF,.
Drrect Page Index
Op Code (B6,.) Register Register Y
Operand (02,.)
,. -
+ 11234,. 1 + 1 00E6,.I= 131C,.
16