Assembly Code Generation - part#2

This is 2nd post in the series of assembly code generation.

Part - I

In this post, I am writing the possible assembly code generated from a typical if expression.

cgen(if e1 == e2 then e3 else e4)

  #generate code for e1 that will put
  #e1 evaluation in $a0
  cgen(e1)
  sw $a0 0($sp) #push the result to stack
  addiu $sp $sp 4

  #generate code for e2 evaluation, this will
  #will put result of e2 evaluation in $a0
  cgen(e2)

  #load the result of e1 evaluation
  #from stack in temp register $t1
  lw $t1 4($sp)
  addiu $sp $sp 4

  #check if $a0 and $t1 are equal, jump to
  #label true_branch if they are equal or else
  #continue
  beq $a0 $t1 true_branch

  #we come to this this point only if value of
  #e1 and e2 evaluation were different, here
  #we generate code for else case
  cgen(e4)

  #after code for else branch, unconditionally jump  to label
  #endif which is the label generated in the
  #end
  jumpto endif

  #true_branch label, we come here if e1 and e2 evaluated
  #to same value
  true_branch:
  cgen(e3)

  #the label endif
  endif:

  #code beyond the if expression follows...