mu/shell/global.mu

type global {
  name: (handle array byte)
  value: (handle cell)
}

type global-table {
  data: (handle array global)
  final-index: int
}

fn initialize-globals _self: (addr global-table) {
  var self/esi: (addr global-table) <- copy _self
  var data-ah/eax: (addr handle array global) <- get self, data
  populate data-ah, 0x10
  append-primitive self, "+"
  append-primitive self, "-"
  append-primitive self, "*"
  append-primitive self, "/"
}

fn append-primitive _self: (addr global-table), name: (addr array byte) {
  var self/esi: (addr global-table) <- copy _self
  var final-index-addr/ecx: (addr int) <- get self, final-index
  increment *final-index-addr
  var curr-index/ecx: int <- copy *final-index-addr
  var data-ah/eax: (addr handle array global) <- get self, data
  var data/eax: (addr array global) <- lookup *data-ah
  var curr-offset/esi: (offset global) <- compute-offset data, curr-index
  var curr/esi: (addr global) <- index data, curr-offset
  var curr-name-ah/eax: (addr handle array byte) <- get curr, name
  copy-array-object name, curr-name-ah
  var curr-value-ah/eax: (addr handle cell) <- get curr, value
  new-primitive-function curr-value-ah, curr-index
}

fn lookup-symbol-in-globals _sym: (addr cell), out: (addr handle cell), _globals: (addr global-table), trace: (addr trace) {
  var sym/eax: (addr cell) <- copy _sym
  var sym-data-ah/eax: (addr handle stream byte) <- get sym, text-data
  var _sym-data/eax: (addr stream byte) <- lookup *sym-data-ah
  var sym-data/edx: (addr stream byte) <- copy _sym-data
  var globals/esi: (addr global-table) <- copy _globals
  {
    compare globals, 0
    break-if-=
    var global-data-ah/eax: (addr handle array global) <- get globals, data
    var global-data/eax: (addr array global) <- lookup *global-data-ah
    var final-index/ecx: (addr int) <- get globals, final-index
    var curr-index/ecx: int <- copy *final-index
    {
      compare curr-index, 0
      break-if-<
      var curr-offset/ebx: (offset global) <- compute-offset global-data, curr-index
      var curr/ebx: (addr global) <- index global-data, curr-offset
      var curr-name-ah/eax: (addr handle array byte) <- get curr, name
      var curr-name/eax: (addr array byte) <- lookup *curr-name-ah
      var found?/eax: boolean <- stream-data-equal? sym-data, curr-name
      {
        compare found?, 0/false
        break-if-=
        var curr-value/eax: (addr handle cell) <- get curr, value
        copy-object curr-value, out
        return
      }
      curr-index <- decrement
      loop
    }
  }
  # otherwise error "unbound symbol: ", sym
  var stream-storage: (stream byte 0x40)
  var stream/ecx: (addr stream byte) <- address stream-storage
  write stream, "unbound symbol: "
  rewind-stream sym-data
  write-stream stream, sym-data
  trace trace, "error", stream
}

# a little strange; goes from value to name and selects primitive based on name
fn apply-primitive _f: (addr cell), args-ah: (addr handle cell), out: (addr handle cell), env-h: (handle cell), _globals: (addr global-table), trace: (addr trace) {
  var f/esi: (addr cell) <- copy _f
  var f-index-a/ecx: (addr int) <- get f, index-data
  var f-index/ecx: int <- copy *f-index-a
  var globals/eax: (addr global-table) <- copy _globals
  var global-data-ah/eax: (addr handle array global) <- get globals, data
  var global-data/eax: (addr array global) <- lookup *global-data-ah
  var f-offset/ecx: (offset global) <- compute-offset global-data, f-index
  var f-value/ecx: (addr global) <- index global-data, f-offset
  var f-name-ah/ecx: (addr handle array byte) <- get f-value, name
  var f-name/eax: (addr array byte) <- lookup *f-name-ah
  {
    var is-add?/eax: boolean <- string-equal? f-name, "+"
    compare is-add?, 0/false
    break-if-=
    apply-add args-ah, out, env-h, trace
    return
  }
  abort "unknown primitive function"
}

fn apply-add _args-ah: (addr handle cell), out: (addr handle cell), env-h: (handle cell), trace: (addr trace) {
  trace-text trace, "eval", "apply +"
  var args-ah/eax: (addr handle cell) <- copy _args-ah
  var _args/eax: (addr cell) <- lookup *args-ah
  var args/esi: (addr cell) <- copy _args
  var _env/eax: (addr cell) <- lookup env-h
  var env/edi: (addr cell) <- copy _env
  # TODO: check that args is a pair
  var empty-args?/eax: boolean <- nil? args
  compare empty-args?, 0/false
  {
    break-if-=
    error trace, "+ needs 2 args but got 0"
    return
  }
  # args->left->value
  var first-ah/eax: (addr handle cell) <- get args, left
  var first/eax: (addr cell) <- lookup *first-ah
  var first-type/ecx: (addr int) <- get first, type
  compare *first-type, 1/number
  {
    break-if-=
    error trace, "first arg for + is not a number"
    return
  }
  var first-value/ecx: (addr float) <- get first, number-data
  # args->right->left->value
  var right-ah/eax: (addr handle cell) <- get args, right
#?   dump-cell right-ah
#?   abort "aaa"
  var right/eax: (addr cell) <- lookup *right-ah
  # TODO: check that right is a pair
  var second-ah/eax: (addr handle cell) <- get right, left
  var second/eax: (addr cell) <- lookup *second-ah
  var second-type/edx: (addr int) <- get second, type
  compare *second-type, 1/number
  {
    break-if-=
    error trace, "second arg for + is not a number"
    return
  }
  var second-value/edx: (addr float) <- get second, number-data
  # add
  var result/xmm0: float <- copy *first-value
  result <- add *second-value
  new-float out, result
}