Echelon Neuron - Manual (Page 139)

XOR_R (Exclusive Or and Return)
The XOR_R instruction performs a logical exclusive OR (XOR) for two numbers
and performs a return-from-call operation. The XOR_R instruction uses the
implicit addressing mode. The XOR_R instruction retrieves both TOS and
NEXT from the data stack and performs a bitwise logical XOR for them. TOS
and NEXT are consumed, and the result is placed in TOS. The operation clears
the Carry flag. The return-from-call operation loads the instruction pointer (IP)
with the return address from the return stack.
The XOR_R instruction applies to Series 3100, 5000, and 6000 devices.
Syntax:
The XOR_R instruction requires no operands:
XOR_R
Table 59 describes the attributes of the XOR_R instruction.
Table 59. XOR_R Instruction
Instruction Hexadecimal
Opcode
Instruction
Size (Bytes)
CPU Cycles
Required
Affect on
Carry Flag
XOR_R 5F 1 7 Cleared
Example:
The following example performs the operation 2 XOR 3 and performs the return-
from-call operation. The example assumes that the return stack contains the
address of the caller to which the XOR_R instruction returns.
pushs #2 ; (2, -, -)
pushs #3 ; (3, 2, -)
xor_r ; (1, -, -)
The value of TOS after this code executes is 3 because 2 XOR 3 = 1. After
completing the logical XOR operation, the XOR_R instruction performs the
return-from-call operation.
Neuron Assembly Language Reference 129