#! /usr/bin/env ruby
`rake`
require "./parser.rb"
$indx_map=-8
$var_map={}
$tab_level=-1
def generate_expr(expression)
  $tab_level+=1
  $tab_level.times do
    print "-"
  end
  code=""
  p expression
  case expression[:type]
  when :number
    code+="mov rax,#{expression[:value]}\n"
  when :neg
    code+=generate_expr(expression[:expr])
    code+="neg rax\n"
  when :comp
    code+=generate_expr(expression[:expr])
    code+="not rax\n"
  when :lneg
    code+=generate_expr(expression[:expr])
    code+="cmp rax,0\n"
    code+="mov rax,0\n"
    code+="sete al\n"
  when :var
    code+="mov rax,[rbp#{$var_map[expression[:name]][1]}]\n"
  when :assign
    code+=generate_expr(expression[:expr])
    code+="mov [rbp#{$var_map[expression[:name]][1]}],rax\n"
  when :comma
    code+=generate_expr(expression[:expr1])
    code+=generate_expr(expression[:expr2])
  when :seteq
    expression[:type]=expression[:op]
    name=expression[:name]
    expression.delete :op
    expression.delete :name
    code+=generate_expr({:type=>:assign,:name=>name,:expr=>expression})
  else
    code+=generate_expr(expression[:expr1])
    code+="push rax\n"
    code+=generate_expr(expression[:expr2])
    code+="pop rcx\n"
    case expression[:type]
    when :plus
      code+="add rax,rcx\n"
    when :minus
      code+="push rax\n"
      code+="push rcx\n"
      code+="pop rax\n"
      code+="pop rcx\n"
      code+="sub rax,rcx\n"
    when :mul
      code+="imul rax,rcx\n"
    when :div
      code+="push rax\n"
      code+="push rcx\n"
      code+="pop rax\n"
      code+="pop rcx\n"
      code+="mov edx,0\n"
      code+="idiv ecx\n"
    when :mod
      code+="push rax\n"
      code+="push rcx\n"
      code+="pop rax\n"
      code+="pop rcx\n"
      code+="mov edx,0\n"
      code+="idiv ecx\n"
      code+="mov eax,edx\n"
    when :eq
      code+="cmp rax,rcx\n"
      code+="mov rax,0\n"
      code+="sete al\n"
    when :ne
      code+="cmp rax,rcx\n"
      code+="mov rax,0\n"
      code+="setne al\n"
    when :ge
      code+="cmp rax,rcx\n"
      code+="mov rax,0\n"
      code+="setge al\n"
    when :le
      code+="cmp rax,rcx\n"
      code+="mov rax,0\n"
      code+="setle al\n"
    when :gt
      code+="cmp rax,rcx\n"
      code+="mov rax,0\n"
      code+="setgt al\n"
    when :lt
      code+="cmp rax,rcx\n"
      code+="mov rax,0\n"
      code+="setlt al\n"
    when :lor
      code+="or eax,ecx\n"
      code+="mov eax,0\n"
      code+="setne al\n"
    when :land
      code+="cmp ecx,0\n"
      code+="setne cl\n"
      code+="cmp eax,0\n"
      code+="mov eax,0\n"
      code+="setne al\n"
      code+="and al,cl\n"
    when :shl
      code+="push rax\n"
      code+="push rcx\n"
      code+="pop rax\n"
      code+="pop rcx\n"
      code+="shl rax,cl\n"
    when :shr
      code+="push rax\n"
      code+="push rcx\n"
      code+="pop rax\n"
      code+="pop rcx\n"
      code+="shr rax,cl\n"
    when :and
      code+="and rax,rcx\n"
    when :or
      code+="or rax,rcx\n"
    when :xor
      code+="xor rax,rcx\n"
    end
  end
  $tab_level-=1
  return code
end
def generate_statement(statement)
  $tab_level+=1
  $tab_level.times do
    print "-"
  end
  p statement
  code=""
  case statement[:type]
  when :return
    code+=generate_expr(statement[:expr])
    code+="mov rsp,rbp\n"
    code+="pop rbp\n"
    code+="ret\n"
  when :vardecl
    code+="push 0\n"
    $var_map[statement[:varname]]=[statement[:vartype],$indx]
    $indx-=8
  when :vardeclinit
    code+=generate_expr(statement[:init])
    code+="push rax\n"
    $var_map[statement[:varname]]=[statement[:vartype],$indx]
    $indx-=8
  when :expr
    code+=generate_expr(statement[:expr])
  end
  $tab_level-=1;
  return code
end
def generate_block(block)
  code=""
  for statement in block
    code+=generate_statement(statement)
  end
  return code
end
def generate_func(func)
  code=""
  $indx=-8
  $var_map={}
  code+=".globl _#{func[:name]}\n"
  code+="_#{func[:name]}:\n"
  code+="push rbp\n"
  code+="mov rbp,rsp\n"
  code+=generate_block(func[:code])
  code+="mov rax,0\n"
  code+="mov rsp,rbp\n"
  code+="pop rbp\n"
  code+="ret\n"
  return code
end
def generate(ast)
  code=""
  for func in ast
    code+=generate_func(func)
  end
  return code
end
program=File.read("main.c")
p CX86.new.tokenize(program)
ast=CX86.new.parse(program)
code=generate(ast)
#puts code
f=File.open("out.asm","w")
f.puts code
f.close
puts `gcc -masm=intel -o out out.asm;./out;echo $?`