Class: N65::INESHeader

Inherits:
InstructionBase show all
Defined in:
lib/n65/directives/ines_header.rb

Constant Summary collapse

DEFAULTS = 
{
  prog: 1,
  char: 0,
  mapper: 0,
  mirror: 0,
  battery_backed: 0,
  fourscreen_vram: 0,
  prog_ram: 0,
  tv: 0
}.freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from InstructionBase

#unresolved_symbols?

Constructor Details

#initialize(prog, char, mapper, mirror, battery_backed, fourscreen_vram, prog_ram, tv) ⇒ INESHeader

Construct a header



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# File 'lib/n65/directives/ines_header.rb', line 45

def initialize(prog, char, mapper, mirror, battery_backed, fourscreen_vram, prog_ram, tv)
  @prog = prog
  @char = char
  @mapper = mapper
  @mirror = mirror
  @battery_backed = battery_backed
  @fourscreen_vram = fourscreen_vram
  @prog_ram = prog_ram
  @tv = tv
end

Instance Attribute Details

#battery_backed ⇒ Object (readonly)

Returns the value of attribute battery_backed.



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# File 'lib/n65/directives/ines_header.rb', line 8

def battery_backed
  @battery_backed
end

#char ⇒ Object (readonly)

Returns the value of attribute char.



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# File 'lib/n65/directives/ines_header.rb', line 8

def char
  @char
end

#fourscreen_vram ⇒ Object (readonly)

Returns the value of attribute fourscreen_vram.



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# File 'lib/n65/directives/ines_header.rb', line 8

def fourscreen_vram
  @fourscreen_vram
end

#mapper ⇒ Object (readonly)

Returns the value of attribute mapper.



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# File 'lib/n65/directives/ines_header.rb', line 8

def mapper
  @mapper
end

#mirror ⇒ Object (readonly)

Returns the value of attribute mirror.



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# File 'lib/n65/directives/ines_header.rb', line 8

def mirror
  @mirror
end

#prog ⇒ Object (readonly)

Returns the value of attribute prog.



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# File 'lib/n65/directives/ines_header.rb', line 8

def prog
  @prog
end

#prog_ram ⇒ Object (readonly)

Returns the value of attribute prog_ram.



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# File 'lib/n65/directives/ines_header.rb', line 8

def prog_ram
  @prog_ram
end

#tv ⇒ Object (readonly)

Returns the value of attribute tv.



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# File 'lib/n65/directives/ines_header.rb', line 8

def tv
  @tv
end

Class Method Details

.parse(line) ⇒ Object 



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# File 'lib/n65/directives/ines_header.rb', line 21

def self.parse(line)
  match_data = line.match(/^\.ines (.+)$/)
  return nil if match_data.nil?

  header = JSON.parse(match_data[1])
  header = header.each_with_object({}) do |(key, val), hash|
    hash[key.to_sym] = val
  end

  header = DEFAULTS.merge(header)

  INESHeader.new(
    header[:prog],
    header[:char],
    header[:mapper],
    header[:mirror],
    header[:battery_backed],
    header[:fourscreen_vram],
    header[:prog_ram],
    header[:tv]
  )
end

Instance Method Details

#emit_bytes ⇒ Object

Emit the header bytes



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# File 'lib/n65/directives/ines_header.rb', line 62

def emit_bytes
  mapper_lo_nybble = (@mapper & 0x0f)
  mapper_hi_nybble = (@mapper & 0xf0) >> 4

  flag6 = 0
  flag6 |= 0x1 if @mirror == 1
  flag6 |= 0x2 if @battery_backed == 1
  flag6 |= 0x8 if @fourscreen_vram == 1
  flag6 |= (mapper_lo_nybble << 4)

  flag7 = 0
  flag7 |= (mapper_hi_nybble << 4)

  [0x4E, 0x45, 0x53, 0x1a,
   @prog & 0xff,
   @char & 0xff,
   flag6 & 0xff,
   flag7 & 0xff,
   @prog_ram & 0xff,
   0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0]
end

#exec(assembler) ⇒ Object

Exec function the assembler will call



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# File 'lib/n65/directives/ines_header.rb', line 57

def exec(assembler)
  assembler.set_ines_header(self)
end

#to_s ⇒ Object

Display



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# File 'lib/n65/directives/ines_header.rb', line 85

def to_s
  [".ines {\"prog\": #{@prog}, \"char\": #{@char}, \"mapper\": #{@mapper}, ",
   "\"mirror\": #{@mirror}}, \"battery_backed\": #{@battery_backed}, ",
   "\"fourscreen_vram\": #{@fourscreen_vram}, \"prog_ram\": #{@prog_ram}, ",
   "\"tv\": #{@tv}"].join
end