samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/benchmark_fannkuchredux.t

@@ -0,0 +1,148 @@
+--[[
+  The Computer Language Benchmarks Game
+  http://shootout.alioth.debian.org/
+ 
+  contributed by Ledrug Katz
+ 
+ ]]
+
+
+local C = {
+    printf = terralib.externfunction("printf", terralib.types.funcpointer(rawstring,int,true)),
+    exit = terralib.externfunction("exit", int -> {}),
+    atoi = terralib.externfunction("atoi", rawstring -> int)
+}
+
+-- this depends highly on the platform.  It might be faster to use
+-- char type on 32-bit systems; it might be faster to use unsigned.
+
+elem = int
+
+s = global(elem[16])
+t = global(elem[16])
+
+maxflips = global(int)
+max_n = global(int)
+odd = global(bool)
+checksum = global(int)
+
+terra flip()
+    var i = max_n
+    var x : &elem = t
+    var y : &elem = s
+    var c : elem
+    
+    while i > 0 do
+        i = i - 1
+        @x = @y
+        x = x + 1
+        y = y + 1
+    end
+    
+    i = 1
+    
+    repeat
+        x = t
+        y = t + t[0]
+        while x < y do
+            c = @x
+            @x = @y
+            x = x + 1
+            @y = c
+            y = y - 1
+        end
+        i = i + 1
+    until t[t[0]] == 0
+    --C.printf("flip %d\n",i);
+    return i
+end
+
+
+terra rotate(n : int)
+    var c = s[0]
+    for i = 0,n do
+        s[i] = s[i+1] 
+    end
+    s[n] = c
+    --C.printf("rotate(%d) %d\n",n,c);
+end
+
+
+terra tk(n : int)
+    var i = 0
+    var f : int
+    var c : elem[16]
+    
+    for i = 0,16 do
+        c[i] = 0
+    end
+    
+    while i < n do
+        rotate(i)
+        if c[i] >= i then
+            c[i] = 0
+            i = i + 1
+            goto continue
+        end
+        
+        c[i] = c[i] + 1
+        i = 1
+        odd = not odd
+        if s[0] ~= 0 then
+            if s[s[0]] ~= 0 then
+                f = flip()
+            else
+                f = 1
+            end
+            if f > maxflips then
+                maxflips = f
+            end
+            --C.printf("f = %d\n",f)
+            if odd then
+                checksum = checksum - f
+            else
+                checksum = checksum + f
+            end
+        end
+        ::continue::
+    end
+   
+end
+
+
+terra doit(N : int)
+    maxflips = 0
+    odd = false
+    checksum = 0
+    max_n = N
+    if max_n < 3 or max_n > 15 then
+      C.printf("range: must be 3 <= n <= 12\n")
+      C.exit(1)
+    end
+    
+    for i = 0,max_n do
+        s[i] = i
+    end
+    tk(max_n)
+    C.printf("%d\nPfannkuchen(%d) = %d\n", checksum, max_n, maxflips)
+    return checksum
+end
+
+terra main(argc : int, v : &&int8)
+    if argc < 2 then
+      C.printf("usage: %s number\n", v[0])
+      C.exit(1);
+    end
+    
+    doit(C.atoi(v[1]))
+    return 0
+end
+
+local test = require("test")
+
+doit:compile()
+print(test.time(function()
+    test.eq(doit(10),73196)
+end))
+
+terralib.saveobj("benchmark_fannkuchredux", { main = main } )