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STORE DOUBLE-BYTE INDIRECT:
STD @Rn [ 7n ]
The low-order ACC byte is stored into memory location
whose address resides in Rn, and Rn is the incremented
by 1. The high-order ACC byte is stored into the memory
location whose address resides in the incremented Rn, and Rn
is again incremented by 1. Branch conditions reflect the ACC
contents which are not disturbed. The carry is cleared.
EXAMPLE:
15 34 A0 SET R5 $A034 ;Load pointers R5, R6
16 22 90 SET R6 $9022 ;with $A034 and $9022
65 LDD @R5 ;Move double byte from
76 STD @R6 ;$A034-35 to $9022-23.
;Both pointers incremented by 2.
POP INDIRECT:
POP @Rn [ 8n ]
The low-order ACC byte is loaded from the memory location
whose address resides in Rn after Rn is decremented by 1,
and the high order ACC byte is cleared. Branch conditions
reflect the final 2-byte ACC contents which will always be
positive and never minus one. The carry is cleared. Because
Rn is decremented prior to loading the ACC, single byte
stacks may be implemented with the ST @Rn and POP @Rn ops
(Rn is the stack pointer).
EXAMPLE:
15 34 A0 SET R5 $A034 ;Init stack pointer
10 04 00 SET R0 4 ;Load 4 into ACC
55 ST @R5 ;Push 4 onto stack
10 05 00 SET R0 5 ;Load 5 into ACC
55 ST @R5 ;Push 5 onto stack
10 06 00 SET R0 6 ;Load 6 into ACC
55 ST @R5 ;Push 6 onto stack
85 POP @R5 ;Pop 6 off stack into ACC
85 POP @R5 ;Pop 5 off stack
85 POP @R5 ;Pop 4 off stack
STORE POP INDIRECT:
STP @Rn [ 9n ]
The low-order ACC byte is stored into the memory location
whose address resides in Rn after Rn is decremented by 1.
Branch conditions will reflect the 2-byte ACC contents which
are not modified. STP @Rn and POP @Rn are used together to
move data blocks beginning at the greatest address and
working down. Additionally, single-byte stacks may be
implemented with the STP @Rn ops.