(define-module (backend emitter traverse)
  #:export (prog-ir
            subrout-ir
            instr-ir
            allocate-ir
            mov-ir
            ret-ir
            neg-ir
            not-ir
            allocate-ir
            reg-ir
            stack-ir
            imm-ir))


(define (prog-ir srout)
  (string-append/shared srout ".section .note.GNU-stack,\"\",@progbits\n"))

(define (srout-ir label instrs)
  (format #f "    .globl ~a
~a:
\tpushq\t%rbp
\tmovq\t%rsp, %rbp
~a" label label (apply string-append/shared instrs)))

(define (mov-ir src dst)
  (format #f "\tmovl\t~a, ~a\n" src dst))

(define (ret-ir)
  "\tmovq\t%rbp, %rsp
\tpopq\t%rbp
\tret\n")

(define (neg-ir dst)
  (emit-unary "negl" dst))

(define (not-ir dst)
  (emit-unary "notl" dst))

(define (plus-ir src dst)
  (emit-binary "addl" src dst))

(define (minus-ir src dst)
  (emit-binary "subl" src dst))

(define (mult-ir src dst)
  (emit-binary "imull" src dst))

(define (div-ir src)
  (emit-unary "idivl" src))

(define (cdq-ir)
  (format #f "\tcdq\n"))

(define (alloc-ir size)
  (format #f "\tsubq\t$~a, %rsp\n" size))

(define (reg-ir r)
  (format #f "%~a" r))

(define (stack-ir loc)
  (format #f "~a(%rbp)" loc))

(define (imm-ir int)
  (format #f "$~a" int))

(define (emit-unary instr dst)
  (format #f "\t~a\t~a\n" instr dst))

(define (emit-binary instr src dst)
  (format #f "\t~a\t~a, ~a\n" instr src dst))