removed unused code and more documentation cleanup

lib/waterfoul.rb

@@ -6,7 +6,6 @@ require "waterfoul/interrupt"
 require "waterfoul/mmu"
 require "Waterfoul/timer"
 require "waterfoul/cpu"
-require "waterfoul/sound"
 require "waterfoul/errors"
 require "waterfoul/sdl"
 require "waterfoul/screen"

lib/waterfoul/libc.rb

@@ -1,6 +0,0 @@
-module LibC
-  extend FFI::Library
-  ffi_lib FFI::Library::LIBC
-
-  attach_function :memcpy, [:pointer, :pointer, :size_t], :pointer
-end

lib/waterfoul/mmu.rb

@@ -1,10 +1,12 @@
 require 'waterfoul/boot_rom'
 
 module Waterfoul
-  # The MMU (Memory Management Unit) in a chip in the device that acts a switch.
-  # It allows programs to interact with subsytems like the GPU and IO depending
-  # on the location in memory when reading from or writing to seeing the CPU
-  # does not implement any IO instructions.
+  # The MMU (Memory Management Unit) in a chip in the device that is the
+  # interface to hardware for reading and writing to memory.
+  #
+  # The MMU also provides the program a way to interact with hardware
+  # like the PPU and IO using memory registers. This is due to the CPU
+  # not having any IO instructions.
   class MMU
     MEMORY_SIZE = 65536 # bytes
     # unmap boot rom register address

lib/waterfoul/render/background.rb

@@ -1,65 +0,0 @@
-module Waterfoul
-  module Render
-    class Background
-      class << self
-        def render
-          line = current_line
-          line_width = line * SCREEN_WIDTH
-
-          if IO::LCDControl.bg_display
-            # tile and map select
-            tiles_select = IO::LCDControl.bg_tile_select
-            map_select = IO::LCDControl.bg_map_select
-            # x pixel offset
-            scx = $mmu.read_byte 0xFF43
-            # y pixel offset
-            scy = $mmu.read_byte 0xFF42
-            # adjusted line with y offset
-            line_adjusted = line + scy
-            # get position of tile row to read
-            y_offset = (line_adjusted / 8) * 32
-            # relative line number in tile
-            tile_line = line_adjusted % 8
-            # relative line number offset
-            tile_line_offset = tile_line * 2
-
-            0.upto(31) do |x|
-              tile = 0
-              if tiles_select == 0x8800
-                tile = signed_value $mmu.read_byte(map_select + y_offset + x)
-                tile += 128
-              else
-                tile = $mmu.read_byte map_select + y_offset + x
-              end
-
-              line_pixel_offset = x * 8
-              tile_select_offset = tile * 16
-              tile_address = tiles_select + tile_select_offset + tile_line_offset
-
-              byte_1 = $mmu.read_byte tile_address
-              byte_2 = $mmu.read_byte (tile_address + 1)
-
-              0.upto(7) do |pixelx|
-                buffer_addr = (line_pixel_offset + pixelx - scx)
-
-                next if (buffer_addr >= SCREEN_WIDTH)
-
-                pixel = (byte_1 & (0x1 << (7 - pixelx)) > 0) ? 1 : 0
-                pixel |= (byte_2 & (0x1 << (7 - pixelx)) > 0) ? 2 : 0
-                position = line_width + buffer_addr
-                palette = $mmu.read_byte 0xFF47
-                color = (palette >> (pixel * 2)) & 0x3
-
-                @framebuffer[position] = color
-              end
-            end
-          else
-            0.upto(SCREEN_WIDTH) do |i|
-              @framebuffer[line_width + i] = 0
-            end
-          end
-        end
-      end
-    end
-  end
-end

lib/waterfoul/screen.rb

@@ -1,6 +1,5 @@
 module Waterfoul
   class Screen
-
     WINDOW_WIDTH = 480
     WINDOW_HEIGHT = 432
 

lib/waterfoul/skip_boot.rb

@@ -1,20 +1,17 @@
 module Waterfoul
-  # Set the state of the emulator as defined to the same state as it typically
-  # is after it has finished running the bootloader and ready to execute the
-  # game program.
-
-  # This lets us run the game without needing to execute the boot rom
-  # every time the emulator is started.
+  # set the state of the CPU and memory to the same state when the boot
+  # program has finished executing. This lets us run the game without
+  # needing to execute the boot rom every time the emulator is started.
   class SkipBoot
     def self.set_state(cpu)
-      # CPU registers
+      # set cpu register state
       cpu.set_register :pc, 0x100
       cpu.set_register :af, 0x1B0
       cpu.set_register :bc, 0x13
       cpu.set_register :de, 0xD8
       cpu.set_register :hl, 0x14D
       cpu.set_register :sp, 0xFFFE
-      # IO registers
+      # set IO reigster state
       $mmu.write_byte 0xFF10, 0x80
       $mmu.write_byte 0xFF11, 0xBF
       $mmu.write_byte 0xFF12, 0xF3
@@ -37,6 +34,7 @@ module Waterfoul
       $mmu.write_byte 0xFF49, 0xFF
       # unmap the boot rom
       $mmu.write_byte 0xFF50, 0x1
+
       cpu
     end
   end

lib/waterfoul/sound.rb

@@ -1,11 +0,0 @@
-module Waterfoul
-  class Sound
-    def initialize
-      @clock = 0
-    end
-
-    def step(cpu_time)
-      @clock += cpu_time
-    end
-  end
-end