If the source register's LSB (in SRC1/dest) is cleared (the value is even), the location where the core will execute the next instruction is pointed to by the destination register (in SRC2). Prepare it in advance !
The Imm16 field is not used because the negation field already provides with a XOR.
This instruction is also aliased from JE.
See also the other instructions of the JMP group : JMP, JNZ, JO/JNE, JS/JNS