3Com CoreBuilder 3500, Implementation Manual

Page: 231 / 592

The Packet Filtering Language 231
le (less than or equal
to) 1 byte Pops two values from the stack and performs an
unsigned comparison. If the first is less than or equal to
the second, a byte containing the non-zero value is
pushed onto the stack; otherwise, a byte containing 0
is pushed. The contents of the stack determine the size
of the operands.
gt (greater than) 1 byte Pops two values from the stack and performs an
unsigned comparison. If the first is greater than the
second, a byte containing the non-zero value is pushed
onto the stack; otherwise, a byte containing 0 is
pushed. The contents of the stack determine size of
the operands.
ge (greater than or
equal to) 1 byte Pops two values from the stack and performs an
unsigned comparison. If the first is greater than or
equal to the second, a byte containing the non-zero
value is pushed onto the stack; otherwise, a byte
containing 0 is pushed. The contents of the stack
determine the size of the operands.
and (bit-wise AND) 1 byte Pops two values from the stack and pushes the bit-wise
AND of these values back onto the stack. The contents
of the stack determine the size of the operands and the
result.
This is a bit-wise operator. Each bit of the operands is
logically compared to produce the resulting bit
or (bit-wise OR) 1 byte Pops two values from the stack and pushes the bit-wise
OR of these values back onto the stack. The contents
of the stack determine the operand size and the result.
This is a bit-wise operator. Each bit of the operands is
logically compared to produce the resulting bit
xor (bit-wise
exclusive-OR) 1 byte Pops two values from the stack and pushes the bit-wise
exclusive
- OR of these values back onto the stack. The
contents of the stack determines the operand size and
the result.
This is a bit-wise operator. Each bit of the operands is
logically compared to produce the resulting bit
not 1 byte Pops a byte from the stack; if its value is non-zero, a
byte containing 0 is pushed back onto the stack.
Otherwise, a byte containing the value is pushed back
onto the stack.
Table 33
Packet Filtering Opcodes (continued)
Opcode
Memory
Requirements
Description