From Intellivision Wiki
|Instruction Name||Branch on External|
|CP1610 Clock Cycles||7 or 9|
|Opcode Range||$0210-$21F, $0230-$23F|
The Branch on External opcode (BEXT) is a two-decle opcode that is a part of the Branch family of opcodes. This instruction causes the CP1610 to branch if the external pins EBCA0-EBCA3 match the specified value. If this condition is true, the CP1610 branches to the address specified by the following parameters.
Format - Decle #1 Format - Word #2 (All 16 bits are significant) 0000:0010:00d1:cccc aaaa:aaaa:aaaa:aaaa
d indicates the direction of the branch such that: d == 0 indicates to branch in the forward direction d == 1 indicates to branch in the reverse direction
cccc The value to assert on external pins EBCA0-EBCA3. The input EBCI determines whether the branch gets taken.
aaaaaaaaaaaaaaaa indicates the amount of offset
See the Branch opcode family documentation for more information.