diff options
Diffstat (limited to 'atk16_emu')
| -rw-r--r-- | atk16_emu/emu.py | 43 | ||||
| -rw-r--r-- | atk16_emu/memory.py | 27 |
2 files changed, 60 insertions, 10 deletions
diff --git a/atk16_emu/emu.py b/atk16_emu/emu.py index 0b4e675..d519e5f 100644 --- a/atk16_emu/emu.py +++ b/atk16_emu/emu.py @@ -129,7 +129,10 @@ class Machine: self.steps_taken = 0 self.running = False - self.is_in_irq = False + + self.interrupts = Interrupts(4) + self.is_critical_section: bool = False + self.active_interrupt_line = None self.peripherals_enabled = peripherals_enabled if peripherals_enabled: @@ -190,6 +193,13 @@ class Machine: new_machine.running = self.running + new_machine.interrupts = Interrupts(self.interrupts.n) + for i in range(self.interrupts.n): + new_machine.interrupts.interrupt_lines[i] = self.interrupts.interrupt_lines[i] + + new_machine.is_critical_section = self.is_critical_section + new_machine.active_interrupt_line = self.active_interrupt_line + return new_machine def mem_read(self, addr: int): @@ -211,6 +221,9 @@ class Machine: self.peripherals.graphics.activate_tpu() elif addr == 0xE7F2 and value == 0b10: self.peripherals.graphics.activate_ppu() + elif addr == 0xE7F3: + state = value & 1 + self.is_critical_section = state == 1 elif 0xF800 <= addr <= 0xFFFF: self.peripherals.graphics.write(addr, value) elif addr == 0xE7F0: @@ -268,18 +281,26 @@ class Machine: raise ValueError(f"Invalid flag number: {n}") def set_irq_line(self, line: int): - if not self.is_in_irq: - self.ipc.value = self.pc.value - isr_addr_pointer = 0x10 + line # see bootstrap.atk16 vector table - isr_addr = self.mem_read(isr_addr_pointer) - self.pc.value = isr_addr - self.is_in_irq = True + self.interrupts.set_interrupt(line) def step(self): if not self.running: raise RuntimeError("Machine is not running") self.steps_taken += 1 + + priority_interrupt_line = self.interrupts.get_priority_interrupt() + if priority_interrupt_line is not None and not self.is_critical_section: + # TODO: instead of handling interrupts in Python like this, maybe emulate + # ISRP0 and ISRP1 instructions properly? Should be the same effect, + # ISRP0-1 are kind of magical instructions. + self.active_interrupt_line = priority_interrupt_line + self.ipc.value = self.pc.value + isr_addr_pointer = 0x10 + priority_interrupt_line # see bootstrap.atk16 vector table + isr_addr = self.mem_read(isr_addr_pointer) + self.pc.value = isr_addr + self.is_critical_section = True + pc_addr = self.pc.value self.pc.step() @@ -358,7 +379,6 @@ class Machine: case ISRP0(): # interrupt service routine, read store PC in IPC register, set PC to ISRA value - raise NotImplementedError() case ISRP1(): @@ -368,7 +388,12 @@ class Machine: case RTI(): # return from interrupt routine, read PC from IPC register self.pc.value = self.ipc.value - self.is_in_irq = False + self.is_critical_section = False + if self.active_interrupt_line is None: + raise RuntimeError("RTI without active interrupt line") + + self.interrupts.clear_interrupt(self.active_interrupt_line) + self.active_interrupt_line = None case HLT(): self.running = False diff --git a/atk16_emu/memory.py b/atk16_emu/memory.py index 2ce9c85..a27344d 100644 --- a/atk16_emu/memory.py +++ b/atk16_emu/memory.py @@ -53,4 +53,29 @@ class RAM: if value < 0 or value >= 2 ** self.data_bits: raise ValueError(f"Value {value} is out of range for {self.data_bits}-bit RAM") - self.memory[addr] = value
\ No newline at end of file + self.memory[addr] = value + + +class Interrupts: + def __init__(self, n: int): + self.n = n + self.interrupt_lines = [False] * n + + def set_interrupt(self, i: int): + if i < 0 or i >= self.n: + raise ValueError(f"Interrupt {i} is out of range for {self.n}-interrupt system") + + self.interrupt_lines[i] = True + + def clear_interrupt(self, i: int): + if i < 0 or i >= self.n: + raise ValueError(f"Interrupt {i} is out of range for {self.n}-interrupt system") + + self.interrupt_lines[i] = False + + def get_priority_interrupt(self) -> int | None: + for i in range(self.n): + if self.interrupt_lines[i]: + return i + + return None |