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hackVM.py
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hackVM.py
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import sys
import os
def stripCommentsAndEmptyLines(lines):
resultLines = []
for line in lines:
# Processing lines
if (not line.startswith("//")) and line != "":
resultLines.append(line.split("//")[0])
return resultLines
compilationUnitFilename = os.path.basename(sys.argv[0]).split('.')[0]
segmentMappings = {
'local' : 'LCL',
'argument' : 'ARG',
'this' : 'THIS',
'that' : 'THAT',
}
callCount = 0
def getPushCode(line):
result = []
cmdSegments = line.split(' ')
memoryType = cmdSegments[1]
address = cmdSegments[2]
if memoryType == 'constant':
result.extend(["@" + address, "D=A"])
result.extend(["@SP", "A=M", "M=D"])
elif memoryType in ['local', 'argument', 'this','that']:
keyword = segmentMappings[memoryType]
result.extend(['@' + address, 'D=A']) # Load the offset into the d register
result.extend(['@' + keyword, 'M=M+D', 'A=M', 'D=M']) # Move the address by this offset and read the value into D
result.extend(['@SP', 'A=M', 'M=D']) # Setting top of the stack memory to value
result.extend(['@' + address, 'D=A']) # Loading the offset into the d register
result.extend(['@' + keyword, 'M=M-D']) # Subtracting from the given memory register
elif memoryType == 'temp':
result.extend(['@' + str(5 + int(address)), 'D=M'])
result.extend(['@SP', 'A=M', 'M=D'])
elif memoryType == 'pointer':
pointerType = ('THIS' if address == '0' else 'THAT')
result.extend(['@' + pointerType, 'D=M'])
result.extend(['@SP', 'A=M', 'M=D'])
elif memoryType == 'static':
result.extend(['@' + compilationUnitFilename + '.' + address, 'D=M'])
result.extend(['@SP','A=M', 'M=D'])
result.extend(['@SP', 'M=M+1']) # Moving the SP up
return result
def getPopCode(line):
result = []
cmdSegments = line.split(' ')
memoryType = cmdSegments[1]
address = cmdSegments[2]
# If it's in one of those registers it's simply loaded into corresponding address
if memoryType in ['local', 'argument', 'this','that']:
keyword = segmentMappings[memoryType]
result.extend(['@' + address, 'D=A', '@' + keyword, 'M=M+D'])
result.extend(['@SP', 'A=M-1', 'D=M'])
result.extend(['@' + keyword, 'A=M', 'M=D'])
result.extend(['@' + address, 'D=A', '@' + keyword, 'M=M-D'])
# Special handling for temp memory
elif memoryType == 'temp':
result.extend(['@SP', 'A=M-1', 'D=M'])
result.extend(['@' + str(5 + int(address)), 'M=D'])
elif memoryType == 'pointer':
pointerType = ('THIS' if address == '0' else 'THAT')
result.extend(['@SP', 'A=M-1', 'D=M'])
result.extend(['@' + pointerType, 'M=D'])
elif memoryType == 'static':
result.extend(['@SP', 'A=M-1', 'D=M'])
result.extend(['@' + compilationUnitFilename + '.' + address, 'M=D'])
result.extend(['@SP', 'M=M-1']) # Moving the SP down
return result
def getOperationCode(cmd):
result = []
if cmd in ["add","sub"]:
operation = ('+' if cmd == 'add' else '-')
result.extend(['@SP', 'M=M-1', 'A=M', 'D=M'])
result.extend(['@SP', 'A=M-1', 'M=M' + operation + 'D'])
elif cmd in ['eq', 'lt', 'gt']:
mappings = {'eq' : 'JEQ', 'lt' : 'JLT', 'gt' : 'JGT'}
keyword = mappings[cmd]
result.extend(['@SP', 'M=M-1', 'A=M', 'D=M']) # Loading First value from the stack into d
result.extend(['@SP', 'M=M-1', 'A=M', 'D=M-D']) # Subtracting second value from the first
result.extend(['@CondLabel.' + str(currentJumpLabel) + ".True"]) # If true jump to to true label
result.extend(['D;' + keyword])
result.extend(['@SP', 'A=M', 'M=0']) # else set the contents of the SP to 0
result.extend(['@CondLabel.' + str(currentJumpLabel) + ".End", '0;JMP'])
result.extend(['(CondLabel.' + str(currentJumpLabel) + ".True)"])
result.extend(['@SP', 'A=M', 'M=-1']) # set the contents SP to all 1
result.extend(['(CondLabel.' + str(currentJumpLabel) + ".End)"])
result.extend(['@SP', 'M=M+1']) # Increment the stack pointer (because we have decremented it twice)
currentJumpLabel += 1
elif cmd == 'neg':
result.extend(['@SP', 'A=M-1', 'M=-M'])
elif cmd in ['and', 'or']:
operation = ('&' if cmd == 'and' else '|')
result.extend(['@SP', 'M=M-1', 'A=M', 'D=M'])
result.extend(['@SP', 'A=M-1', 'M=M'+ operation +'D'])
elif cmd == 'not':
result.extend(['@SP', 'A=M-1', 'M=!M'])
return result
def getCodeForLines(lines):
global callCount
result = []
currentJumpLabel = 0
for line in lines:
cmdSegments = line.split(' ')
firstSegment = cmdSegments[0]
result.append('// ' + line)
if firstSegment == 'push':
result.extend(getPushCode(line))
elif firstSegment == 'pop':
result.extend(getPopCode(line))
elif firstSegment == 'label':
labelName = cmdSegments[1]
result.extend(['(' + labelName + ')'])
elif firstSegment == 'if-goto':
labelName = cmdSegments[1]
result.extend(['@SP', 'A=M-1', 'D=M', '@SP', 'M=M-1'])
result.extend(['@' + labelName, 'D;JNE'])
elif firstSegment == 'goto':
labelName = cmdSegments[1]
result.extend(['@' + labelName, '0;JMP'])
elif firstSegment == 'function':
functionName = cmdSegments[1]
argCount = int(cmdSegments[2])
vmCommands = ['label ' + functionName]
# Initializing localArgs
for i in range(0, argCount):
vmCommands.extend(['push constant 0', 'pop local ' + str(i)])
result.extend(getCodeForLines(vmCommands))
elif firstSegment == 'return':
result.extend(['@LCL', 'D=M', '@temp1', 'M=D']) # endFrame = LCL
result.extend(['@5', 'D=D-A', 'A=D', 'D=M', '@temp2', 'M=D']) # retAddr = *(endFrame - 5)
result.extend(['@SP', 'A=M-1', 'D=M', '@ARG', 'A=M', 'M=D']) # *ARG=pop() -- Get the correct pointer
result.extend(['@ARG', 'D=M+1', '@SP', 'M=D']) # SP = ARG + 1
result.extend(['@1', 'D=A', '@temp1', 'A=M-D', 'D=M', '@THAT', 'M=D']) # THAT = *(endFrame - 1)
result.extend(['@2', 'D=A', '@temp1', 'A=M-D', 'D=M', '@THIS', 'M=D']) # THIS = *(endFrame - 2)
result.extend(['@3', 'D=A', '@temp1', 'A=M-D', 'D=M', '@ARG', 'M=D']) # ARG = *(endFrame - 3)
result.extend(['@4', 'D=A', '@temp1', 'A=M-D', 'D=M', '@LCL', 'M=D']) # LCL = *(endFrame - 4)
result.extend(['@temp2', 'A=M', '0;JMP'])
elif firstSegment == 'call':
functionName = cmdSegments[1]
nArgs = int(cmdSegments[2])
argDecrement = nArgs + 5
result.extend(['@return.' + str(callCount), 'D=A', '@SP', 'A=M', 'M=D', '@SP', 'M=M+1']) # push returnAddress
result.extend(['@LCL', 'A=M', 'D=M', '@SP', 'A=M', 'M=D', '@SP', 'M=M+1']) # push LCL
result.extend(['@ARG', 'A=M', 'D=M', '@SP', 'A=M', 'M=D', '@SP', 'M=M+1']) # push ARG
result.extend(['@THIS', 'A=M', 'D=M', '@SP', 'A=M', 'M=D', '@SP', 'M=M+1']) # push THIS
result.extend(['@THAT', 'A=M', 'D=M', '@SP', 'A=M', 'M=D', '@SP', 'M=M+1']) # push THAT
result.extend(['@' + str(argDecrement), 'D=A', '@SP', 'A=M', 'D=M-D', '@ARG', 'M=D']) # reposition ARG
result.extend(['@SP', 'A=M', 'D=M', '@LCL', 'M=D']) # reposition LCL
result.extend(getCodeForLines(['goto ' + functionName]))
result.extend(['(return. ' + str(callCount) + ')'])
callCount += 1
# Arithmetic operations
else:
result.extend(getOperationCode(firstSegment))
return result
def getFileContents(filePath):
file = open(filePath, 'r')
fileContents = file.read()
file.close()
return fileContents
result = []
filename = sys.argv[1]
if os.path.isfile(filename):
print filename + " is filename"
destFilename = filename.split('.')[0] + ".asm"
file = open(filename, 'r')
fileContents = file.read()
lines = fileContents.split("\n")
lines = stripCommentsAndEmptyLines(lines)
result = getCodeForLines(lines)
destContents = ('\n').join(result)
# print destContents
file = open(destFilename, 'w')
file.write(destContents)
elif os.path.isdir(filename):
# List files in dir
vmFiles = filter(lambda x: x.endswith(".vm"), os.listdir(filename))
vmFilesPath = map(lambda x: filename + "\\" + x, vmFiles)
for filePath in vmFilesPath:
print "FilePath: " + filePath + " \n"
print getFileContents(filePath)
print vmFilesPath