Echelon Neuron - Manual (Page 110)

POPD (Pop Pointer Direct)
The POPD instruction pops the two bytes from TOS and NEXT on the data stack
into the specified pointer register. The POPD instruction uses the pointer direct
addressing mode. The pointer-register expression must be in the range 0 to 3.
Because the data stack grows towards higher addresses, NEXT holds the most-
significant byte (MSB) and TOS holds the least-significant byte (LSB) of the 16-
bit value to be popped.
The POPD instruction applies to Series 3100, 5000, and 6000 devices.
Syntax:
The POPD instruction requires one operand to specify the pointer register:
POPD [0]
POPD [1]
POPD [2]
POPD [3]
Table 39 describes the attributes of the POPD instruction.
Table 39. POPD Instruction
Instruction Hexadecimal
Opcode
Instruction
Size (Bytes)
CPU Cycles
Required
Affect on
Carry Flag
POPD [0] F0 1 6 None
POPD [1] F1 1 6 None
POPD [2] F2 1 6 None
POPD [3] F3 1 6 None
Example:
The following example preserves the P1 and P2 pointer registers by pushing
them onto the stack before performing operations that could affect these
registers, then popping them from the stack.
P1 EQU 1
P2 EQU 2
; Preserve P1, P2.
pushd [P1]
pushd [P2]
...
popd [P1]
popd [P2]
ret ; return to caller
100 Neuron Assembly Language Instruction Statements