gem5/src/arch/x86/isa/microasm.isa

// -*- mode:c++ -*-

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// Authors: Gabe Black

////////////////////////////////////////////////////////////////////
//
//  Code to "assemble" microcode sequences
//

let {{
    class MicroOpStatement:
        def __init__(self):
            self.className = ''
            self.label = ''
            self.args = []

        def getAllocator(self, labelDict = {}):
            args = ''
            for arg in self.args:
                if arg.has_key("operandConst"):
                    args += ", %s" % arg["operandConst"]
                elif arg.has_key("operandCode"):
                    args += ", %s" % arg["operandCode"]
                elif arg.has_key("operandLabel"):
                    if not labelDict.has_key(arg["operandLabel"]):
                        print "Unrecognized label %s!" % arg["operandLabel"]
                    args += ", %s" % labelDict[arg["operandLabel"]]
                else:
                    print "Unrecognized operand type!"
            return 'new %s(machInst %s)' % (self.className, args)


    def assembleMicro(code):
        # This function takes in a block of microcode assembly and returns
        # a python list of objects which describe it.

        # Keep this around in case we need it later
        orig_code = code
        # A list of the statements we've found thus far
        statements = []

        # Regular expressions to pull each piece of the statement out at a
        # time. Each expression expects the thing it's looking for to be at
        # the beginning of the line, so the previous component is stripped
        # before continuing.
        labelRe = re.compile(r'^[ \t]*(?P<label>[a-zA-Z_]\w*)[ \t]:')
        lineRe = re.compile(r'^(?P<line>[^\n][^\n]*)$')
        classRe = re.compile(r'^[ \t]*(?P<className>[a-zA-Z_]\w*)')
        # This recognizes three different flavors of operands:
        # 1. Raw decimal numbers composed of digits between 0 and 9
        # 2. Code beginning with "{" and continuing until the first "}"
        #         ^ This one might need revising
        # 3. A label, which starts with a capital or small letter, or
        #    underscore, which is optionally followed by a sequence of
        #    capital or small letters, underscores, or digts between 0 and 9
        opRe = re.compile( \
            r'^[ \t]*((?P<operandLabel>[a-zA-Z_]\w*)|(?P<operandConst>[0-9][0-9]*)|(\{(?P<operandCode>[^}]*)\}))')
        lineMatch = lineRe.search(code)
        while lineMatch != None:
            statement = MicroOpStatement()
            # Get a line and seperate it from the rest of the code
            line = lineMatch.group("line")
            print "Parsing line %s" % line
            code = lineRe.sub('', code, 1)

            # Find the label, if any
            labelMatch = labelRe.search(line)
            if labelMatch != None:
                statement.label = labelMatch.group("label")
                print "Found label %s." % statement.label
            # Clear the label from the statement
            line = labelRe.sub('', line, 1)

            # Find the class name which is roughly equivalent to the op name
            classMatch = classRe.search(line)
            if classMatch == None:
                print "Oh no! I can't find what instruction you want!"
                print "I should really bail out here, but I don't know how!"
            else:
                statement.className = classMatch.group("className")
                print "Found class name %s." % statement.className

            # Clear the class name from the statement
            line = classRe.sub('', line, 1)

            #Find as many arguments as you can
            statement.args = []
            opMatch = opRe.search(line)
            while opMatch is not None:
                statement.args.append({})
                # args is a list of dicts which collect different
                # representations of operand values. Different forms might be
                # needed in different places, for instance to replace a label
                # with an offset.
                for opType in ("operandLabel", "operandConst", "operandCode"):
                    if opMatch.group(opType):
                        statement.args[-1][opType] = opMatch.group(opType)
                if len(statement.args[-1]) == 0:
                    print "I had a problem parsing an operand!"
                line = opRe.sub('', line, 1)
                print "Found operand %s." % statement.args[-1]
                opMatch = opRe.search(line)
            print "Found operands", statement.args

            # Add this statement to our collection
            statements.append(statement)

            # Get the next line
            lineMatch = lineRe.search(code)
        return statements

    def buildLabelDict(ops):
        labels = {}
        count = 0
        for op in ops:
            if op.label:
                labels[op.label] = count
            count += 1
}};