cachegen.hs

深入理解计算机系统（computer system：a programmer s perpective)是一本非常经典的教材

{------------------------------------------------------------------------}
{--- Generates C code to simulate various kinds of caches.            ---}
{---                                                      CacheGen.hs ---}
{------------------------------------------------------------------------}

{- 
   This file is part of Cacheprof, a profiling tool for finding
   sources of cache misses in programs.

   Copyright (C) 1999 Julian Seward ([e-mail])
   Home page: http://www.cacheprof.org

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307, USA.

   The GNU General Public License is contained in the file LICENSE.
-}

module Main where
import IO
import System

valid_sizes, valid_linesizes, valid_ways :: [Int]
valid_sizes 
   = [1024,2048,4096,8192,16384,32768,65536,131072,
      262144,524288,1048576,2097152,4194304,8388608,16777216]
valid_ways
   = [1,2,4,8]
valid_linesizes
   = [8,16,32,64,128]

powers_of_two_table :: [(Int,Int)]
powers_of_two_table
   = [(0,1),(1,2),(2,4),(3,8),(4,16),(5,32),(6,64),(7,128),(8,256),
      (9,512),(10,1024),(11,2048),(12,4096),(13,8192),
      (14,16384),(15,32768),(16,65536),(17,131072),(18,262144),
      (19,524288),(20,1048576),(21,2097152),(22,4194304),
      (23,8388608),(24,16777216),(25,33554432),(26,67108864),
      (27,134217728),(28,268435456),(29,536870912),(30,1073741824)]

log2 :: Int -> Int
log2 x
   = case [n | (n, two_to_the_n) <- powers_of_two_table, 
               two_to_the_n == x] of
        [log2_x] -> log2_x
        other    -> error "cachegen: log2"

validConfig [sz, linesz, ways]
   = sz `elem` (map show valid_sizes)
     && linesz `elem` (map show valid_linesizes)
     && ways `elem` (map show valid_ways)

main 
   = getArgs >>= \as ->
     if   length as /= 3 || not (validConfig as)
     then usage as >> exitWith (ExitFailure 1)
     else mkCache (map read as) >> exitWith ExitSuccess

usage as
   = hPutStr stderr (unlines [
        "usage: cachegen size line_size number_of_ways",
        "  where",
        "  size is one of " ++ unwords (map show (take 9 valid_sizes)),
        "                 " ++ unwords (map show (drop 9 valid_sizes)),
        "  line_size is one of " ++ unwords (map show valid_linesizes),
        "  number_of_ways is one of " ++ unwords (map show valid_ways),
        ""   
     ])
        

mkCache :: [Int] -> IO ()
mkCache [sz, linesz, ways]
   = let num_lines = sz `div` linesz
         num_sets  = num_lines `div` ways
         line_bits = log2 linesz
         set_bits  = log2 num_sets
         text      = unlines (the_text num_sets ways 
                                      line_bits set_bits sz linesz)
     in
         putStr text


the_text num_sets ways line_bits set_bits sz linesz
   = [ "",
       "/*  A cache simulator, generated by cachegen.",
       " *     total size    = " ++ show sz ++ " bytes",
       " *     line size     = "  ++ show linesz ++ " bytes",
       " *     associativity = " ++ show ways
                  ++ (if ways == 1 then " (direct-mapped)" else ""),
       " *  This file should be #include-d into cachesim.c.",
       " */",
       "",
       "static UInt32 tags[" ++ show num_sets 
          ++ "][" ++ show ways ++ "];",
       "",
       "static void cachesim_initcache ( void ) ",
       "{",
       "   Int32 set, way;",
       "   for (set = 0; set < " ++ show num_sets ++ "; set++)",
       "      for (way = 0; way < " ++ show ways ++ "; way++)",
       "         tags[set][way] = 0;",
       "}",
       "",
       "__inline__ static UInt32 cachesim_doref ( void* ap )",
       "{",
       "   register UInt32 a   = (UInt32)ap;",
       "   register UInt32 set = (a >> " 
             ++ show line_bits ++ ") & " 
             ++ show (num_sets-1) ++ ";",
       "   register UInt32 tag = (a >> " 
             ++ show (line_bits + set_bits) ++ ");",
       "   register UInt32 tmp;",
       ""
     ]
     ++ concatMap trySet [0 .. ways-1] 
     ++
     [  
       "   {"
     ]
     ++ shiftSequence (ways-1) 
     ++
     [
       "      tags[set][0] = tag;",
       "      return 1;",
       "   }",
       "}",
       ""
     ]

trySet :: Int -> [String]
trySet k
   = [
        "   if (tag == tags[set][" ++ show k ++ "]) {"
     ]
     ++ (if k == 0 then [] 
                   else [ "      tmp = tags[set][" ++ show k ++ "];"])
     ++ shiftSequence k
     ++ (if k == 0 then [] else [  "      tags[set][0] = tmp;"])
     ++
     [
        "      return 0;",
        "   }"
     ]

shiftSequence :: Int -> [String]
shiftSequence k
   = map f [k, k-1 .. 1]
     where
        f i = "      tags[set][" ++ show i 
              ++ "] = tags[set][" ++ show (i-1)
              ++ "];"

{------------------------------------------------------------------------}
{--- end                                                  CacheGen.hs ---}
{------------------------------------------------------------------------}