Shorten comparison/type check code

scm/inc/compiler.scm

(define (primcall-operand1 x)
  (cadr x))
(define (emit-compare)
  (emit "movl $0,  %eax")                ; zero %eax to put the result of the comparison into
  (emit "sete %al")                      ; set low byte of %eax to 1 if cmp succeeded
  (emit "sall $~a,  %eax" boolean-shift) ; construct correctly tagged boolean value
  (emit "xorl $31, %eax"))
(define (emit-expr x)
  (cond
    ((immediate? x)
        (emit "shrl $6, %eax"))
       ((zero?)
        (emit-expr (primcall-operand1 x))
        (emit "cmpl $0,  %eax")                ; x == 0
        (emit "movl $0,  %eax")                ; zero %eax to put the result of the comparison into
        (emit "sete %al")                      ; set low byte of %eax to 1 if cmp succeeded
        (emit "sall $~a,  %eax" boolean-shift) ; construct correctly tagged boolean value
        (emit "xorl $31, %eax"))
        (emit "cmpl $0,  %eax") ; x == 0
        (emit-compare))
       ((integer?)
        (emit-expr (primcall-operand1 x))
        (emit "andl $~a, %eax" #b11)
        (emit "movl $0,  %eax")
        (emit "sete %al")
        (emit "sall $~a,  %eax" boolean-shift)
        (emit "xorl $31, %eax"))
        (emit-compare))
       ((boolean?)
        (emit-expr (primcall-operand1 x))
        (emit "andl $~a, %eax" #b0011111)
        (emit "cmpl $~a,  %eax" #b0011111)
        (emit "movl $0,  %eax")
        (emit "sete %al")
        (emit "sall $~a,  %eax" boolean-shift)
        (emit "xorl $31, %eax"))
        (emit-compare))
       ))))
(define (compile-program x)