about summary refs log tree commit diff stats
path: root/apps/rpn.mu
blob: bd0d721f4556a5f7ec0fb82ad4a93741ef999b1f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
# Integer arithmetic using postfix notation
#
# Limitations:
#   No division yet.
#
# To build:
#   $ ./translate_mu apps/rpn.mu
#
# Example session:
#   $ ./a.elf
#   press ctrl-c or ctrl-d to exit
#   > 1
#   1
#   > 1 1 +
#   2
#   > 1 2 3 + +
#   6
#   > 1 2 3 * +
#   7
#   > 1 2 + 3 *
#   9
#   > 1 3 4 * +
#   13
#   > ^D
#   $
#
# Error handling is non-existent. This is just a prototype.

fn main -> exit-status/ebx: int {
  var in-storage: (stream byte 0x100)
  var in/esi: (addr stream byte) <- address in-storage
  print-string 0, "press ctrl-c or ctrl-d to exit\n"
  # read-eval-print loop
  {
    # print prompt
    print-string 0, "> "
    # read line
    clear-stream in
    read-line-from-real-keyboard in
    var done?/eax: boolean <- stream-empty? in
    compare done?, 0
    break-if-!=
    # parse and eval
    var out/eax: int <- simplify in
    # print
    print-int32-decimal 0, out
    print-string 0, "\n"
    #
    loop
  }
  exit-status <- copy 0
}

type int-stack {
  data: (handle array int)
  top: int
}

fn simplify in: (addr stream byte) -> result/eax: int {
  var word-storage: slice
  var word/ecx: (addr slice) <- address word-storage
  var stack-storage: int-stack
  var stack/esi: (addr int-stack) <- address stack-storage
  initialize-int-stack stack, 0x10
  $simplify:word-loop: {
    next-word in, word
    var done?/eax: boolean <- slice-empty? word
    compare done?, 0
    break-if-!=
    # if word is an operator, perform it
    {
      var is-add?/eax: boolean <- slice-equal? word, "+"
      compare is-add?, 0
      break-if-=
      var _b/eax: int <- pop-int-stack stack
      var b/edx: int <- copy _b
      var a/eax: int <- pop-int-stack stack
      a <- add b
      push-int-stack stack, a
      loop $simplify:word-loop
    }
    {
      var is-sub?/eax: boolean <- slice-equal? word, "-"
      compare is-sub?, 0
      break-if-=
      var _b/eax: int <- pop-int-stack stack
      var b/edx: int <- copy _b
      var a/eax: int <- pop-int-stack stack
      a <- subtract b
      push-int-stack stack, a
      loop $simplify:word-loop
    }
    {
      var is-mul?/eax: boolean <- slice-equal? word, "*"
      compare is-mul?, 0
      break-if-=
      var _b/eax: int <- pop-int-stack stack
      var b/edx: int <- copy _b
      var a/eax: int <- pop-int-stack stack
      a <- multiply b
      push-int-stack stack, a
      loop $simplify:word-loop
    }
    # otherwise it's an int
    var n/eax: int <- parse-decimal-int-from-slice word
    push-int-stack stack, n
    loop
  }
  result <- pop-int-stack stack
}

fn initialize-int-stack _self: (addr int-stack), n: int {
  var self/esi: (addr int-stack) <- copy _self
  var d/edi: (addr handle array int) <- get self, data
  populate d, n
  var top/eax: (addr int) <- get self, top
  copy-to *top, 0
}

fn push-int-stack _self: (addr int-stack), _val: int {
  var self/esi: (addr int-stack) <- copy _self
  var top-addr/ecx: (addr int) <- get self, top
  var data-ah/edx: (addr handle array int) <- get self, data
  var data/eax: (addr array int) <- lookup *data-ah
  var top/edx: int <- copy *top-addr
  var dest-addr/edx: (addr int) <- index data, top
  var val/eax: int <- copy _val
  copy-to *dest-addr, val
  add-to *top-addr, 1
}

fn pop-int-stack _self: (addr int-stack) -> val/eax: int {
$pop-int-stack:body: {
  var self/esi: (addr int-stack) <- copy _self
  var top-addr/ecx: (addr int) <- get self, top
  {
    compare *top-addr, 0
    break-if->
    val <- copy 0
    break $pop-int-stack:body
  }
  subtract-from *top-addr, 1
  var data-ah/edx: (addr handle array int) <- get self, data
  var data/eax: (addr array int) <- lookup *data-ah
  var top/edx: int <- copy *top-addr
  var result-addr/eax: (addr int) <- index data, top
  val <- copy *result-addr
}
}