raze-gles/polymer/eduke32/source/lunatic/bittest.lua

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#!/usr/bin/env luajit
-- Usage: luajit bittest.lua <number or "x"> [-ffi] [-bchk]
local string = require "string"
local bit = require("bit")
local bitar = require "bitar"
local print = print
local tonumber = tonumber
local getticks
if (string.dump) then
-- stand-alone
local os = require "os"
function getticks()
return os.clock()*1000
end
else
-- embedded
getticks = gv.gethitickms
module(...)
end
-- based on example from http://bitop.luajit.org/api.html
local m = string.dump and tonumber(arg[1]) or 1e7
local ffiar_p, boundchk_p = false, false
if (string.dump) then
if (arg[2]=="-ffi" or arg[3]=="-ffi") then
ffiar_p = true
end
if (arg[2]=="-bchk" or arg[3]=="-bchk") then
boundchk_p = true
end
end
function sieve()
local count = 0
local p = {}
if (ffiar_p) then
-- stand-alone using unchecked int32_t array instead of table:
-- on x86_64 approx. 100 vs. 160 ms for m = 1e7
-- (enabling bound checking makes it be around 170 ms)
local ffi = require "ffi"
local pp = ffi.new("int32_t [?]", (m+31)/32 + 1)
p = pp
if (boundchk_p) then
local mt = {
__index = function(tab,idx)
if (idx >= 0 and idx <= (m+31)/32) then
return pp[idx]
end
end,
__newindex = function(tab,idx,val)
if (idx >= 0 and idx <= (m+31)/32) then
pp[idx] = val
end
end,
}
p = setmetatable({}, mt)
end
for i=0,(m+31)/32 do p[i] = -1; end
else
p = bitar.new(m, 1)
end
local t = getticks()
for i=2,m do
if (p:isset(i)) then
count = count + 1
for j=i+i,m,i do p:set0(j); end
end
end
print(string.format("[%s] Found %d primes up to %d (%.02f ms)",
ffiar_p and "ffi-ar"..(boundchk_p and ", bchk" or "") or "tab-ar",
count, m, getticks()-t))
return p
end
if (string.dump) then
local p = sieve()
local t = getticks()
-- test serialization
local p2 = bitar.new(string.match(tostring(p), "'(.*)'"))
print(getticks()-t)
for i=0,#p do
assert(p[i]==p2[i])
end
for i = 3,#p do
p[i] = nil
end
print(p)
print(p-p) -- test set difference
end