;;; factorial.asm: A program that generates the factorials of each
;;;  number from 1 to 22 (22!~=UINT64_MAX).  Using the registers to
;;;  store `n` and `n!`.

  ;; Constants
  %const(limit) 22 %end

  ;; Setup entrypoint
  global main
main:
  ;; $I -> W[0] = 1, $J -> W[1] = 1
  push.word 1
  mov.word 0
  push.word 1
  mov.word 1

  ;; Print `$I: $J`
loopback:
  push.byte '\t'
  print.char
  push.reg.word 0
  print.word
  push.byte ':'
  print.char
  push.byte ' '
  print.char
  push.reg.word 1
  print.word
  push.byte '\n'
  print.char

  ;;  $I += 1
  push.reg.word 0
  push.word 1
  plus.word
  mov.word 0

  ;;  $J *= $I
  push.reg.word 0
  push.reg.word 1
  mult.word
  mov.word 1

  ;; IF $I >= $LIMIT ...
  push.word $limit
  push.reg.word 0
  gte.word
  ;; THEN jump to `loopback`
  jump.if.byte loopback
  ;; ELSE halt
  halt