Class: Zemu::Config::Memory

Inherits:
BusDevice show all
Defined in:
lib/zemu/config.rb

Overview

Memory object.

This is an abstract class from which all other memory objects inherit.

Direct Known Subclasses

RAM, ROM

Instance Method Summary collapse

Methods inherited from BusDevice

#clock, #functions, #interrupt, #interrupt?, #io_read, #io_write, #nmi, #nmi?, #when_setup

Methods inherited from Zemu::ConfigObject

#method_missing

Constructor Details

#initialize ⇒ Memory

Constructor.

Do not use, as this is an abstract class. Use one of the subclasses instead.



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# File 'lib/zemu/config.rb', line 200

def initialize
    if self.class == Zemu::Config::Memory
        raise NotImplementedError, "Cannot construct an instance of the abstract class Zemu::Config::Memory."
    end

    @contents = []

    super

    # Pad contents with 0x00 bytes.
    (@size - @contents.size).times do
        @contents << 0x00
    end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class Zemu::ConfigObject

Instance Method Details

#contents(*args) ⇒ Object

Gets or sets an array of bytes representing the initial state of this memory block.



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# File 'lib/zemu/config.rb', line 217

def contents(*args)
    if args.size.zero?
        return @contents
    else
        @contents = args[0]
    end
end

#from_binary(file) ⇒ Object

Reads the contents of a file in binary format and returns them as an array.



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# File 'lib/zemu/config.rb', line 285

def from_binary(file)
    return File.open(file, "rb") do |f|
        bin = []

        f.each_byte { |b| bin << b }

        bin
    end
end

#mem_read(addr) ⇒ Object

Memory bus read handler.

Handles read access via the memory bus to this device.

Returns the value read, or nil if no value (e.g. if address falls outside range for this device).

Parameters:

  • addr —

    The address being accessed.



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# File 'lib/zemu/config.rb', line 264

def mem_read(addr)
    nil
end

#mem_write(addr, value) ⇒ Object

Memory bus write handler.

Handles write access via the memory bus to this device.

Parameters:

  • addr —

    The address being accessed.

  • value —

    The value being written.



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# File 'lib/zemu/config.rb', line 274

def mem_write(addr, value)
end

#memory ⇒ Object

Parameters used for generating C code to implement this memory block.



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# File 'lib/zemu/config.rb', line 232

def memory
    contents_initializer = ""
    @contents.each_slice(32) do |c|
        contents_initializer += c.map { |b| b.to_s }.join(", ")
        contents_initializer += ",\n"
    end

    m = OpenStruct.new

    m.setup = "zuint8 memory_\#{name}[\#{size}] =\n{\n    \#{contents_initializer}\n};\n"

    m.address = address
    m.size = size
    m.access_read = "memory_#{name}"
    m.access_write = "memory_#{name}"

    m
end

#params ⇒ Object

Valid parameters for this object. Should be extended by subclasses but NOT REPLACED.



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# File 'lib/zemu/config.rb', line 279

def params
    super + %w(address size)
end

#readonly? ⇒ Boolean

Is this memory read-only?

Returns:

  • (Boolean) 


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# File 'lib/zemu/config.rb', line 226

def readonly?
    false
end