1 # Conway's Game of Life
  2 #
  3 # To build:
  4 #   $ ./translate life.mu
  5 # To run:
  6 #   $ qemu-system-i386 disk.img
  7 
  8 fn state _grid: (addr array boolean), x: int, y: int -> _/eax: boolean {
  9   # clip at the edge
 10   compare x, 0
 11   {
 12     break-if->=
 13     return 0/false
 14   }
 15   compare y, 0
 16   {
 17     break-if->=
 18     return 0/false
 19   }
 20   compare x, 0x100/width
 21   {
 22     break-if-<
 23     return 0/false
 24   }
 25   compare y, 0xc0/height
 26   {
 27     break-if-<
 28     return 0/false
 29   }
 30   var idx/eax: int <- copy y
 31   idx <- shift-left 8/log2width
 32   idx <- add x
 33   var grid/esi: (addr array boolean) <- copy _grid
 34   var result/eax: (addr boolean) <- index grid, idx
 35   return *result
 36 }
 37 
 38 fn set-state _grid: (addr array boolean), x: int, y: int, val: boolean {
 39   # don't bother checking bounds
 40   var idx/eax: int <- copy y
 41   idx <- shift-left 8/log2width
 42   idx <- add x
 43   var grid/esi: (addr array boolean) <- copy _grid
 44   var result/eax: (addr boolean) <- index grid, idx
 45   var src/ecx: boolean <- copy val
 46   copy-to *result, src
 47 }
 48 
 49 fn num-live-neighbors grid: (addr array boolean), x: int, y: int -> _/eax: int {
 50   var result/edi: int <- copy 0
 51   # row above: zig
 52   decrement y
 53   decrement x
 54   var s/eax: boolean <- state grid, x, y
 55   {
 56     compare s, 0/false
 57     break-if-=
 58     result <- increment
 59   }
 60   increment x
 61   s <- state grid, x, y
 62   {
 63     compare s, 0/false
 64     break-if-=
 65     result <- increment
 66   }
 67   increment x
 68   s <- state grid, x, y
 69   {
 70     compare s, 0/false
 71     break-if-=
 72     result <- increment
 73   }
 74   # curr row: zag
 75   increment y
 76   s <- state grid, x, y
 77   {
 78     compare s, 0/false
 79     break-if-=
 80     result <- increment
 81   }
 82   subtract-from x, 2
 83   s <- state grid, x, y
 84   {
 85     compare s, 0/false
 86     break-if-=
 87     result <- increment
 88   }
 89   # row below: zig
 90   increment y
 91   s <- state grid, x, y
 92   {
 93     compare s, 0/false
 94     break-if-=
 95     result <- increment
 96   }
 97   increment x
 98   s <- state grid, x, y
 99   {
100     compare s, 0/false
101     break-if-=
102     result <- increment
103   }
104   increment x
105   s <- state grid, x, y
106   {
107     compare s, 0/false
108     break-if-=
109     result <- increment
110   }
111   return result
112 }
113 
114 fn step old-grid: (addr array boolean), new-grid: (addr array boolean) {
115   var y/ecx: int <- copy 0
116   {
117     compare y, 0xc0/height
118     break-if->=
119     var x/edx: int <- copy 0
120     {
121       compare x, 0x100/width
122       break-if->=
123       var n/eax: int <- num-live-neighbors old-grid, x, y
124       # if neighbors < 2, die of loneliness
125       {
126         compare n, 2
127         break-if->=
128         set-state new-grid, x, y, 0/dead
129       }
130       # if neighbors > 3, die of overcrowding
131       {
132         compare n, 3
133         break-if-<=
134         set-state new-grid, x, y, 0/dead
135       }
136       # if neighbors = 2, preserve state
137       {
138         compare n, 2
139         break-if-!=
140         var old-state/eax: boolean <- state old-grid, x, y
141         set-state new-grid, x, y, old-state
142       }
143       # if neighbors = 3, cell quickens to life
144       {
145         compare n, 3
146         break-if-!=
147         set-state new-grid, x, y, 1/live
148       }
149       x <- increment
150       loop
151     }
152     y <- increment
153     loop
154   }
155 }
156 
157 # color a square of size 'side' starting at x*side, y*side
158 fn render-square _x: int, _y: int, color: int {
159   var y/edx: int <- copy _y
160   y <- shift-left 2/log2side
161   var side/ebx: int <- copy 1
162   side <- shift-left 2/log2side
163   var ymax/ecx: int <- copy y
164   ymax <- add side
165   {
166     compare y, ymax
167     break-if->=
168     {
169       var x/eax: int <- copy _x
170       x <- shift-left 2/log2side
171       var xmax/ecx: int <- copy x
172       xmax <- add side
173       {
174         compare x, xmax
175         break-if->=
176         pixel-on-real-screen x, y, color
177         x <- increment
178         loop
179       }
180     }
181     y <- increment
182     loop
183   }
184 }
185 
186 fn render grid: (addr array boolean) {
187   var y/ecx: int <- copy 0
188   {
189     compare y, 0xc0/height
190     break-if->=
191     var x/edx: int <- copy 0
192     {
193       compare x, 0x100/width
194       break-if->=
195       var state/eax: boolean <- state grid, x, y
196       compare state, 0/false
197       {
198         break-if-=
199         render-square x, y, 3/cyan
200       }
201       compare state, 0/false
202       {
203         break-if-!=
204         render-square x, y, 0/black
205       }
206       x <- increment
207       loop
208     }
209     y <- increment
210     loop
211   }
212 }
213 
214 fn main screen: (addr screen), keyboard: (addr keyboard), data-disk: (addr disk) {
215 #?   # allocate on the stack
216 #?   var grid1-storage: (array boolean 0xc000)  # width * height
217 #?   var grid1/esi: (addr array boolean) <- address grid1-storage
218 #?   var grid2-storage: (array boolean 0xc000)  # width * height
219 #?   var grid2/edi: (addr array boolean) <- address grid2-storage
220   # allocate on the heap
221   var grid1-storage: (handle array boolean)
222   var grid1-ah/eax: (addr handle array boolean) <- address grid1-storage
223   populate grid1-ah, 0xc000  # width * height
224   var _grid1/eax: (addr array boolean) <- lookup *grid1-ah
225   var grid1/esi: (addr array boolean) <- copy _grid1
226   var grid2-storage: (handle array boolean)
227   var grid2-ah/eax: (addr handle array boolean) <- address grid2-storage
228   populate grid2-ah, 0xc000  # width * height
229   var _grid2/eax: (addr array boolean) <- lookup *grid2-ah
230   var grid2/edi: (addr array boolean) <- copy _grid2
231   # initialize grid1
232   set-state grid1, 0x80, 0x5f, 1/live
233   set-state grid1, 0x81, 0x5f, 1/live
234   set-state grid1, 0x7f, 0x60, 1/live
235   set-state grid1, 0x80, 0x60, 1/live
236   set-state grid1, 0x80, 0x61, 1/live
237   # render grid1
238   render grid1
239   {
240     var key/eax: byte <- read-key keyboard
241     compare key, 0
242 #?     loop-if-=  # press key to step
243     break-if-!=  # press key to quit  # comment this out to run under bochs; I'm not sure why there's a newline in the keyboard buffer
244     # iter: grid1 -> grid2
245     step grid1, grid2
246     render grid2
247     # iter: grid2 -> grid1
248     step grid2, grid1
249     render grid1
250     loop
251   }
252 }