Home » Instructions » SJMP. It's a special label indicating the current line. 8051 / 8052 Microcontroller Instruction Set SJMP - Short Jump. For this reason there is also an SJMP (short jump) instruction, which is a 2-byte instruction as opposed to the 3-byte LJMP instruction. SJMP and LJMP are the branching instructions that are used to transfering control from one place to another place. 8051 SJMP, AJMP, LJMP Short Absolute and Long Jumps Preview.