Question

The following SPARC program finds the product of an integer raised to a passed in power. There are errors; fix them so that the code correctly runs.

.global exponent
exponent: save %fp, -96, %fp
   ! %i0 = the base number
     ! %i1 = holds the power
     cmp $i0, %g0
     ble expoDone
     mov 1, %l0
loopExpo:
     cmp %i1, %g0
     bge expone
     mov %i0, %o0
     call .mul
     mov %l0, %o1

     mov %g0, %l0
     ba loopExpo
     inc %i1
expoDone:
     mov %l0, %o0
     ret
     return

Answer 1

The issue is with the branch instruction used in the code. We are branching to some branch which does no exist.

bge expone (there is no branch named expone)

It should branch to expDone

The code should be modified as :

.global exponent
exponent: save %fp, -96, %fp
   ! %i0 = the base number
     ! %i1 = holds the power
     cmp $i0, %g0
     ble expoDone
     mov 1, %l0
loopExpo:
     cmp %i1, %g0
     bge expoDone
     mov %i0, %o0
     call .mul
     mov %l0, %o1

     mov %g0, %l0
     ba loopExpo
     inc %i1
expoDone:
     mov %l0, %o0
     ret
     return