1989_MELPS_7700_Software_Manual

Stack Pointer Relative
Mode
Function
Stack pointer relative addressing mode
The contents of a bank-O memory location specified by the value resulting from addition
of the instruction's second byte and the contents of the stack pointer become
the actual data. If, however, the value obtained by adding the contents of the instruction's
second byte and the stack pointer's contents exceeds the bank-O range, the
specified location will be in bank-1.
Instruction: ADC, AND, CMP, DIV, EaR, LOA, MPY, ORA, SBC, STA
ex.
: Mnemonic
ADC A, 02H, S
(m=1)
Machine Code
63 '6 02 '6 -
ex.
: Mnemonic
ADC A, 02H, S
(m=O)
Machine Code
63,6 02 '6
Memory
Memory
DATA
1236'6
Bank-O
A-A+C+
I DATA" i DATAL I ~ {
DATAL
DATAH
1236'6
Bank-O
1--------
-------
f-------
-------
Op Code (63 16 )
Operand (02 16 )
Stack POinter
+1 1234lJ=1236,6
Op Code (63,6)
Operand (02 16 )
Stack POinter
+ @;J=1236'6
f-------
-
1--------
.....
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