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assemblypdp-11

swap on assembly

I wrote swap on assembly, but I'm not sure that my code is right, this is the code 

swap:  mov r1, -(sp)   

   mov (sp) r1
   mov 2(sp) (sp)
   mov r1 2(sp)

   mov (sp)+, r1
   rts pc

swap receives pointer from stack

Solution

  • is sp a stackpointer? There is usually the command ldw rA, 0(rB) (0 is the offset and rB is the address you will load from, the actual data is now in rA). ldw loads a whole word into the memory, ldb loads a byte, stw rA, 0(rB) stores a word. mov usually copies one register to another.