[From Nand to Tetris] 第8章 虚拟机项目 python 实现
为防闲逛至此的看官不知所云： From Nand to Tetris 是一个在线课程，目标是指导学生从 Nand 逻辑门开始从头到尾完成一整套计算机系统。
好像撸串一样的爽快：------芯片--硬件---编译原理---操作系统---应用程序------>
这里提供的是第八章的作业，以供半路摔进坑里的同学们扶一下。。。
人家老师确实是不希望扩散答案，不过我做的过程中遇到很多坑，搞半天后发现全是些脑残原因，实在是浪费时间，希望卡壳的同学们能以增进效率为目的适当参考答案。毕竟学习这种东西，有没有学到手只有自己知道。。。
注释不多，因为代码相当 self-explanatory ，就是书上那些，没自由发挥什么。
如果你是闲逛进来，而且对这块内容有兴趣的话，强烈建议点开上面的课程链接试试，我是真心非常喜欢这门课，请收下我的安利。。。
另外还有第六章的作业答案：第6章 汇编器项目 python 实现
# _*_ coding: utf-8 _*_
import sys
import os
import glob
class C_TYPE:
'''Command Type'''
C_ARITHMETIC, C_PUSH, C_POP, C_LABEL, C_GOTO, C_IF, C_FUNCTION, C_RETURN, C_CALL = range(9)
class Parser:
def __init__(self, fname):
self.finput = open(fname, 'rU')
self.current = None
self.commandPart = []
self.cType = -1
def __exit__(self, exc_type, exc_val, exc_tb):
self.finput.close()
def has_more_commands(self):
self.current = self.finput.readline()
while self.current == '\n' or self.current[:2] == '//':
self.current = self.finput.readline()
return self.current != ''
def advance(self):
self.commandPart = self.current.strip().split(' ')[:3]
if self.commandPart[0] == 'add' or\
self.commandPart[0] == 'sub' or\
self.commandPart[0] == 'neg' or\
self.commandPart[0] == 'eq' or\
self.commandPart[0] == 'gt' or\
self.commandPart[0] == 'lt' or\
self.commandPart[0] == 'and' or\
self.commandPart[0] == 'or' or\
self.commandPart[0] == 'not':
self.cType = C_TYPE.C_ARITHMETIC
elif self.commandPart[0] == 'push':
self.cType = C_TYPE.C_PUSH
elif self.commandPart[0] == 'pop':
self.cType = C_TYPE.C_POP
elif self.commandPart[0] == 'label':
self.cType = C_TYPE.C_LABEL
elif self.commandPart[0] == 'goto':
self.cType = C_TYPE.C_GOTO
elif self.commandPart[0] == 'if-goto':
self.cType = C_TYPE.C_IF
elif self.commandPart[0] == 'function':
self.cType = C_TYPE.C_FUNCTION
elif self.commandPart[0] == 'call':
self.cType = C_TYPE.C_CALL
elif self.commandPart[0] == 'return':
self.cType = C_TYPE.C_RETURN
def command_type(self):
return self.cType
def arg1(self):
if self.command_type() == C_TYPE.C_ARITHMETIC:
return self.commandPart[0]
return self.commandPart[1]
def arg2(self):
return self.commandPart[2]
class CodeWriter:
def __init__(self, fname):
self.foutput = open(fname, 'w')
self.uniqueFlag = 0 # 用于构造唯一的标签，每次使用后加1
self.currentFile = '' # 当前处理的文件的名字
self.currentFunc = '' # 当前处理的函数的名字
def set_file_name(self, fname):
self.currentFile = fname
def write_arithmetic(self, command):
if command == 'add':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@SP\nM=M-1\nA=M\nM=M+D\n@SP\nM=M+1\n')
elif command == 'sub':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@SP\nM=M-1\nA=M\nM=M-D\n@SP\nM=M+1\n')
elif command == 'neg':
self.foutput.write('@SP\nM=M-1\nA=M\nM=-M\n@SP\nM=M+1\n')
elif command == 'eq':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@SP\nM=M-1\nA=M\nD=M-D\n@RET_TRUE'+str(self.uniqueFlag)+'\n'
'D;JEQ\nD=0\n@END'+str(self.uniqueFlag)+'\n0;JMP\n(RET_TRUE'+str(self.uniqueFlag)+')\n'
'D=-1\n(END'+str(self.uniqueFlag)+')\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
self.uniqueFlag += 1
elif command == 'gt':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@SP\nM=M-1\nA=M\nD=M-D\n@RET_TRUE'+str(self.uniqueFlag)+'\n'
'D;JGT\nD=0\n@END'+str(self.uniqueFlag)+'\n0;JMP\n(RET_TRUE'+str(self.uniqueFlag)+')\n'
'D=-1\n(END'+str(self.uniqueFlag)+')\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
self.uniqueFlag += 1
elif command == 'lt':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@SP\nM=M-1\nA=M\nD=M-D\n@RET_TRUE'+str(self.uniqueFlag)+'\n'
'D;JLT\nD=0\n@END'+str(self.uniqueFlag)+'\n0;JMP\n(RET_TRUE'+str(self.uniqueFlag)+')\n'
'D=-1\n(END'+str(self.uniqueFlag)+')\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
self.uniqueFlag += 1
elif command == 'and':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@SP\nM=M-1\nA=M\nM=M&D\n@SP\nM=M+1\n')
elif command == 'or':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@SP\nM=M-1\nA=M\nM=M|D\n@SP\nM=M+1\n')
elif command == 'not':
self.foutput.write('@SP\nM=M-1\nA=M\nM=!M\n@SP\nM=M+1\n')
def write_push_pop(self, command, segment, index):
if command == C_TYPE.C_PUSH:
if segment == 'constant':
self.foutput.write('@'+index+'\nD=A\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif segment == 'local':
self.foutput.write('@LCL\nD=M\n@'+index+'\nA=A+D\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif segment == 'argument':
self.foutput.write('@ARG\nD=M\n@'+index+'\nA=A+D\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif segment == 'this':
self.foutput.write('@THIS\nD=M\n@'+index+'\nA=A+D\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif segment == 'that':
self.foutput.write('@THAT\nD=M\n@'+index+'\nA=A+D\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif segment == 'pointer':
self.foutput.write('@'+str(int(index)+3)+'\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif segment == 'temp':
self.foutput.write('@'+str(int(index)+5)+'\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif segment == 'static':
self.foutput.write('@'+self.currentFile+'.'+index+'\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n')
elif command == C_TYPE.C_POP:
if segment == 'local':
self.foutput.write('@LCL\nD=M\n@'+index+'\nD=A+D\n@R13\nM=D\n@SP\nM=M-1\nA=M\nD=M\n@R13\nA=M\nM=D\n')
elif segment == 'argument':
self.foutput.write('@ARG\nD=M\n@'+index+'\nD=A+D\n@R13\nM=D\n@SP\nM=M-1\nA=M\nD=M\n@R13\nA=M\nM=D\n')
elif segment == 'this':
self.foutput.write('@THIS\nD=M\n@'+index+'\nD=A+D\n@R13\nM=D\n@SP\nM=M-1\nA=M\nD=M\n@R13\nA=M\nM=D\n')
elif segment == 'that':
self.foutput.write('@THAT\nD=M\n@'+index+'\nD=A+D\n@R13\nM=D\n@SP\nM=M-1\nA=M\nD=M\n@R13\nA=M\nM=D\n')
elif segment == 'pointer':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@'+str(int(index)+3)+'\nM=D\n')
elif segment == 'temp':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@'+str(int(index)+5)+'\nM=D\n')
elif segment == 'static':
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@'+self.currentFile+'.'+index+'\nM=D\n')
def write_label(self, label):
self.foutput.write('('+self.currentFunc+'$'+label+')\n') # 构造 (funcName$label) 格式的标记，网站上没提，但书里有
def write_init(self):
self.foutput.write('@256\nD=A\n@SP\nM=D\n')
self.write_call('Sys.init', 0)
def write_goto(self, label):
self.foutput.write('@'+self.currentFunc+'$'+label+'\n0;JMP\n')
def write_if(self, label):
self.foutput.write('@SP\nM=M-1\nA=M\nD=M\n@'+self.currentFunc+'$'+label+'\nD;JNE\n')
def write_call(self, function_name, num_args):
self.foutput.write('@RETURN_ADDRESS'+str(self.uniqueFlag)+'\nD=A\n@SP\nA=M\nM=D\n@SP\nM=M+1\n'
'@LCL\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n'
'@ARG\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n'
'@THIS\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n'
'@THAT\nD=M\n@SP\nA=M\nM=D\n@SP\nM=M+1\n'
'@SP\nD=M\n@'+str(int(num_args)+5)+'\nD=D-A\n@ARG\nM=D\n'
'@SP\nD=M\n@LCL\nM=D\n'
'@'+function_name+'\n0;JMP\n'
'(RETURN_ADDRESS'+str(self.uniqueFlag)+')\n')
self.uniqueFlag += 1
def write_return(self):
self.foutput.write('@LCL\nD=M\n@R13\nM=D\n'
'@5\nA=D-A\nD=M\n@R14\nM=D\n'
'@SP\nM=M-1\nA=M\nD=M\n@ARG\nA=M\nM=D\n'
'@ARG\nD=M+1\n@SP\nM=D\n'
'@R13\nA=M-1\nD=M\n@THAT\nM=D\n'
'@R13\nA=M-1\nA=A-1\nD=M\n@THIS\nM=D\n' # 蠢萌蠢萌的减n次1，比下一句还省一条指令。。。
'@R13\nD=M\n@3\nA=D-A\nD=M\n@ARG\nM=D\n'
'@R13\nD=M\n@4\nA=D-A\nD=M\n@LCL\nM=D\n'
'@R14\nA=M\n0;JMP\n')
def write_function(self, function_name, num_locals):
self.currentFunc = function_name
commandsInitLocals = ''
for i in range(int(num_locals)):
commandsInitLocals += '@LCL\nD=M\n@'+str(i)+'\nA=A+D\nM=0\n'
self.foutput.write('('+function_name+')\n'+commandsInitLocals)
def close(self):
self.foutput.close()
def process_vm_file(fpath):
'''
处理一个 .vm 文件
fpath: 待处理 .vm 文件的绝对路径
'''
parser = Parser(fpath)
writer.set_file_name(os.path.basename(fpath.strip('.vm')))
while parser.has_more_commands():
parser.advance()
if parser.command_type() == C_TYPE.C_PUSH or parser.command_type() == C_TYPE.C_POP:
writer.write_push_pop(parser.command_type(), parser.arg1(), parser.arg2())
elif parser.command_type() == C_TYPE.C_ARITHMETIC:
writer.write_arithmetic(parser.arg1())
elif parser.command_type() == C_TYPE.C_LABEL:
writer.write_label(parser.arg1())
elif parser.command_type() == C_TYPE.C_GOTO:
writer.write_goto(parser.arg1())
elif parser.command_type() == C_TYPE.C_IF:
writer.write_if(parser.arg1())
elif parser.command_type() == C_TYPE.C_CALL:
writer.write_call(parser.arg1(), parser.arg2())
elif parser.command_type() == C_TYPE.C_FUNCTION:
writer.write_function(parser.arg1(), parser.arg2())
elif parser.command_type() == C_TYPE.C_RETURN:
writer.write_return()
# main program
if os.path.isfile(sys.argv[1]) and sys.argv[1].endswith('.vm'): # 参数为 .vm 文件，只翻译一个文件
writer = CodeWriter(os.path.splitext(sys.argv[1])[0]+'.asm')
writer.write_init()
process_vm_file(sys.argv[1])
elif os.path.isdir(sys.argv[1]): # 参数为文件夹，将文件夹中所有文件翻译为 hack 汇编
writer = CodeWriter(sys.argv[1]+'/'+os.path.basename(sys.argv[1])+'.asm')
writer.write_init()
for f in glob.glob(sys.argv[1] + '/*.vm'):
process_vm_file(f)
python
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