Class: PSX::Interrupts

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

Overview

Interrupt Controller Manages hardware interrupts via I_STAT and I_MASK registers

Constant Summary collapse

IRQ_VBLANK =

Interrupt bits

0x001
IRQ_GPU =

Vertical blank

0x002
IRQ_CDROM =

GPU ready

0x004
IRQ_DMA =

CD-ROM

0x008
IRQ_TIMER0 =

DMA transfer complete

0x010
IRQ_TIMER1 =

Timer 0

0x020
IRQ_TIMER2 =

Timer 1

0x040
IRQ_CONTROLLER =

Timer 2

0x080
IRQ_SIO =

Controller/memory card

0x100
IRQ_SPU =

Serial I/O

0x200
IRQ_LIGHTPEN =

Sound

0x400

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Interrupts

Returns a new instance of Interrupts.



22
23
24
25
 
# File 'lib/psx/interrupts.rb', line 22

def initialize
  @stat = 0  # I_STAT - interrupt status (active interrupts)
  @mask = 0  # I_MASK - interrupt mask (enabled interrupts)
end

Instance Attribute Details

#mask ⇒ Object (readonly)

Lightpen (directly active)



20
21
22
 
# File 'lib/psx/interrupts.rb', line 20

def mask
  @mask
end

#stat ⇒ Object (readonly)

Lightpen (directly active)



20
21
22
 
# File 'lib/psx/interrupts.rb', line 20

def stat
  @stat
end

Instance Method Details

#dma! ⇒ Object

Trigger DMA interrupt



66
67
68
 
# File 'lib/psx/interrupts.rb', line 66

def dma!
  request(IRQ_DMA)
end

#gpu! ⇒ Object

Trigger GPU interrupt



61
62
63
 
# File 'lib/psx/interrupts.rb', line 61

def gpu!
  request(IRQ_GPU)
end

#pending? ⇒ Boolean

Check if any unmasked interrupt is pending

Returns:

  • (Boolean) 


51
52
53
 
# File 'lib/psx/interrupts.rb', line 51

def pending?
  (@stat & @mask) != 0
end

#read_mask ⇒ Object 



31
32
33
 
# File 'lib/psx/interrupts.rb', line 31

def read_mask
  @mask
end

#read_stat ⇒ Object 



27
28
29
 
# File 'lib/psx/interrupts.rb', line 27

def read_stat
  @stat
end

#request(irq) ⇒ Object

Request an interrupt



46
47
48
 
# File 'lib/psx/interrupts.rb', line 46

def request(irq)
  @stat |= irq
end

#timer!(n) ⇒ Object

Trigger timer interrupt



71
72
73
74
75
76
77
 
# File 'lib/psx/interrupts.rb', line 71

def timer!(n)
  case n
  when 0 then request(IRQ_TIMER0)
  when 1 then request(IRQ_TIMER1)
  when 2 then request(IRQ_TIMER2)
  end
end

#vblank! ⇒ Object

Trigger VBlank interrupt



56
57
58
 
# File 'lib/psx/interrupts.rb', line 56

def vblank!
  request(IRQ_VBLANK)
end

#write_mask(value) ⇒ Object 



41
42
43
 
# File 'lib/psx/interrupts.rb', line 41

def write_mask(value)
  @mask = value & 0x7FF
end

#write_stat(value) ⇒ Object 



35
36
37
38
39
 
# File 'lib/psx/interrupts.rb', line 35

def write_stat(value)
  # Writing to I_STAT acknowledges (clears) interrupts.
  # On PSX: write 0 to a bit clears it (ack), write 1 leaves it unchanged.
  @stat &= value
end