Class: PSX::RAM

Inherits:
Object
  • Object
show all
Defined in:
lib/psx/ram.rb

Constant Summary collapse

SIZE =

2 MB

2 * 1024 * 1024
MASK = 
SIZE - 1

Instance Method Summary collapse

Constructor Details

#initialize ⇒ RAM

Returns a new instance of RAM.



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# File 'lib/psx/ram.rb', line 8

def initialize
  @data = ("\x00" * SIZE).b  # Force binary encoding
end

Instance Method Details

#read16(offset) ⇒ Object 



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# File 'lib/psx/ram.rb', line 16

def read16(offset)
  offset &= MASK
  @data.getbyte(offset) | (@data.getbyte(offset + 1) << 8)
end

#read32(offset) ⇒ Object 



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# File 'lib/psx/ram.rb', line 21

def read32(offset)
  offset &= MASK
  @data.getbyte(offset) |
    (@data.getbyte(offset + 1) << 8) |
    (@data.getbyte(offset + 2) << 16) |
    (@data.getbyte(offset + 3) << 24)
end

#read8(offset) ⇒ Object 



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# File 'lib/psx/ram.rb', line 12

def read8(offset)
  @data.getbyte(offset & MASK)
end

#write16(offset, value) ⇒ Object 



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# File 'lib/psx/ram.rb', line 33

def write16(offset, value)
  offset &= MASK
  @data.setbyte(offset, value & 0xFF)
  @data.setbyte(offset + 1, (value >> 8) & 0xFF)
end

#write32(offset, value) ⇒ Object 



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# File 'lib/psx/ram.rb', line 39

def write32(offset, value)
  offset &= MASK
  @data.setbyte(offset, value & 0xFF)
  @data.setbyte(offset + 1, (value >> 8) & 0xFF)
  @data.setbyte(offset + 2, (value >> 16) & 0xFF)
  @data.setbyte(offset + 3, (value >> 24) & 0xFF)
end

#write8(offset, value) ⇒ Object 



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# File 'lib/psx/ram.rb', line 29

def write8(offset, value)
  @data.setbyte(offset & MASK, value & 0xFF)
end