Here is a solution that works if we know we can access up to three bytes of memory after the last length field. That is, if we can always use Load to get the length field from memory:
L R1,(,R14) R1 = Integer plus trailing junk LHI R15,4 S R15,0(,Rn) R15 = 4-length SLL R15,3 R15 = (4-length)*8 * Length 0 => 32 * Length 1 => 24 * Length 2 => 16 * Length 3 => 8 * Length 4 => 0 SRL R1,(,R15) R1 = Integer ST R1,Local_integer Task 2) is also taken care of: a zero-length length fields results in a zero integer (but not -1). Task 3) is easily implemented: replace the SRL by an SRA. Taks 4) wouldn't be that hard either: use Grande instructions. Fred!
