简单的Ruby直接到机器码的生成器(X86) RPGMaker兼容

2016 年 5 月 7 日

毕竟Bellard大牛的OTCC里面就是到处飞机器码，并且，他是一边解析词法符号一边就直接产生了，真是棒棒的不按套路却又无比正经的写法

=begin
Author: 晴兰@66RPG UID=131313
LICENSE: CC-BY-SA 3.0 [url]http://creativecommons.org/licenses/by-sa/3.0/deed.zh[/url]
Purpose: Simple Machine Code Generator. Limited operation supported
=end

CallWindowProc = Win32API.new 'user32', 'CallWindowProcW', 'pLLLL', 'L'

def prolog(num_of_var = nil)
  [0x55, 0x8b, 0xec].pack("C*") + (num_of_var ? [0x83, 0354, num_of_var * 4].pack("C*") : "")
end

def epilog
  [0xc9, 0xc2, 0x10].pack("CCS")
end

def render(list, num_of_var = nil)
 prolog(num_of_var) + render_rec(list) + epilog
end

def check_var(list)
  return -4 * list[1]  if list[0] == :var
  raise "lvalue required for #{list.inspect}"
end

def render_rec(list)  
  case list.first
    when :lit
      [0xb8, list[1]].pack("CL")
    when :arg
      [0x8b, 0105, 4 + list[1] * 4].pack("C*")
    when :do
      list[1..-1].map{|x| render_rec(x)}.join
    when :var
      [0x8b, 0105, -4 * list[1] ].pack("C*")
    when :assign
      id = check_var(list[1])
      render_rec(list[2]) + [0x89, 0105, id].pack("C*")
    when :+, :-, :&, :^, :|
      render_rec(list[2]) + "\x50" + render_rec(list[1]) + 
      [0132, "+|ab&-^".index(list.first.to_s) << 3 | 3, 0302].pack("C*")
    when :<, :>, :'==', :'!=', :>=, :<=
      v = list.first.to_s
      l = v.length
      f = v.ord rescue v[0]
      u = "0000G+000000<HF>".index((f + (l > 1 ? 10 : 0)).chr)
      render_rec(list[2]) + "\x50" + render_rec(list[1]) + 
      [0132, 073, 0302, 0x0f, 0x90 + u, 0300, 0x81, 0340, 0xff, 0x00, 0x00, 0x00].pack("C*")
    when :nil; ""
    when :if
      cond, thenpart, elsepart = list[1..-1].map{|x| render_rec(x)}
      thenpart += [0xe9, elsepart.length].pack("CL")
      cond     += [0x85, 0300, 0x75, 0x05, 0xe9, thenpart.length].pack("CCCCCL")
      cond     + thenpart + elsepart
    when :for
      init, cond, incr, body = list[1..-1].map{|x| render_rec(x)}
      addbyte = [0x85, 0300, 0x75, 0x05, 0xe9, body.size + incr.size + 5].pack("CCCCCL")
      fbody = body + incr + 
              [0xe9, -(body.size + incr.size + cond.size + addbyte.size + 5)].pack("CL")
      init + cond + addbyte + fbody
  end
end

x = render(
 [:do,
   [:assign, [:var, 1], [:lit, 0]], 
   [:for, 
       [:assign, [:var, 2], [:lit, 1]],
       [:<, [:var, 2], [:lit, 101]],
       [:assign, [:var, 2], [:+, [:var, 2], [:lit, 1]]],
       [:assign, [:var, 1], [:+, [:var, 1], [:var, 2]]]
   ],
   [:var, 1]
 ], 2
)

=begin
 int var1 = 0;
 for(int var2 = 1; var2 < 101; var2+=1)
    var1 += var2;
 return var1
=end

p CallWindowProc.call x, 0, 0, 0, 0  #=>5050

=begin

Author: 晴兰@66RPG UID=131313

LICENSE: CC-BY-SA 3.0 [url]http://creativecommons.org/licenses/by-sa/3.0/deed.zh[/url]

Purpose: Simple Machine Code Generator. Limited operation supported

=end

CallWindowProc = Win32API.new 'user32', 'CallWindowProcW', 'pLLLL', 'L'

def prolog(num_of_var = nil)

[0x55, 0x8b, 0xec].pack("C*") + (num_of_var ? [0x83, 0354, num_of_var * 4].pack("C*") : "")

end

def epilog

[0xc9, 0xc2, 0x10].pack("CCS")

end

def render(list, num_of_var = nil)

prolog(num_of_var) + render_rec(list) + epilog

end

def check_var(list)

return -4 * list[1] if list[0] == :var

raise "lvalue required for #{list.inspect}"

end

def render_rec(list)

case list.first

when :lit

[0xb8, list[1]].pack("CL")

when :arg

[0x8b, 0105, 4 + list[1] * 4].pack("C*")

when :do

list[1..-1].map{|x| render_rec(x)}.join

when :var

[0x8b, 0105, -4 * list[1] ].pack("C*")

when :assign

id = check_var(list[1])

render_rec(list[2]) + [0x89, 0105, id].pack("C*")

when :+, :-, :&, :^, :|

render_rec(list[2]) + "\x50" + render_rec(list[1]) +

[0132, "+|ab&-^".index(list.first.to_s) << 3 | 3, 0302].pack("C*")

when :<, :>, :'==', :'!=', :>=, :<=

v = list.first.to_s

l = v.length

f = v.ord rescue v[0]

u = "0000G+000000<HF>".index((f + (l > 1 ? 10 : 0)).chr)

render_rec(list[2]) + "\x50" + render_rec(list[1]) +

[0132, 073, 0302, 0x0f, 0x90 + u, 0300, 0x81, 0340, 0xff, 0x00, 0x00, 0x00].pack("C*")

when :nil; ""

when :if

cond, thenpart, elsepart = list[1..-1].map{|x| render_rec(x)}

thenpart += [0xe9, elsepart.length].pack("CL")

cond += [0x85, 0300, 0x75, 0x05, 0xe9, thenpart.length].pack("CCCCCL")

cond + thenpart + elsepart

when :for

init, cond, incr, body = list[1..-1].map{|x| render_rec(x)}

addbyte = [0x85, 0300, 0x75, 0x05, 0xe9, body.size + incr.size + 5].pack("CCCCCL")

fbody = body + incr +

[0xe9, -(body.size + incr.size + cond.size + addbyte.size + 5)].pack("CL")

init + cond + addbyte + fbody

end

x = render(

[:do,

[:assign, [:var, 1], [:lit, 0]],

[:for,

[:assign, [:var, 2], [:lit, 1]],

[:<, [:var, 2], [:lit, 101]],

[:assign, [:var, 2], [:+, [:var, 2], [:lit, 1]]],

[:assign, [:var, 1], [:+, [:var, 1], [:var, 2]]]

[:var, 1]

], 2

)

=begin

int var1 = 0;

for(int var2 = 1; var2 < 101; var2+=1)

var1 += var2;

return var1

=end

p CallWindowProc.call x, 0, 0, 0, 0 #=>5050