201 lines
7.4 KiB
Zig
201 lines
7.4 KiB
Zig
const std = @import("std");
|
|
const util = @import("../util.zig");
|
|
|
|
const TimerControl = @import("io.zig").TimerControl;
|
|
const Io = @import("io.zig").Io;
|
|
const Scheduler = @import("../scheduler.zig").Scheduler;
|
|
const Event = @import("../scheduler.zig").Event;
|
|
const Arm7tdmi = @import("../cpu.zig").Arm7tdmi;
|
|
|
|
pub const TimerTuple = std.meta.Tuple(&[_]type{ Timer(0), Timer(1), Timer(2), Timer(3) });
|
|
const log = std.log.scoped(.Timer);
|
|
|
|
pub fn create(sched: *Scheduler) TimerTuple {
|
|
return .{ Timer(0).init(sched), Timer(1).init(sched), Timer(2).init(sched), Timer(3).init(sched) };
|
|
}
|
|
|
|
pub fn read(comptime T: type, tim: *const TimerTuple, addr: u32) ?T {
|
|
const nybble = @truncate(u4, addr);
|
|
|
|
return switch (T) {
|
|
u32 => switch (nybble) {
|
|
0x0 => @as(T, tim.*[0].cnt.raw) << 16 | tim.*[0].getCntL(),
|
|
0x4 => @as(T, tim.*[1].cnt.raw) << 16 | tim.*[1].getCntL(),
|
|
0x8 => @as(T, tim.*[2].cnt.raw) << 16 | tim.*[2].getCntL(),
|
|
0xC => @as(T, tim.*[3].cnt.raw) << 16 | tim.*[3].getCntL(),
|
|
else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, addr }),
|
|
},
|
|
u16 => switch (nybble) {
|
|
0x0 => tim.*[0].getCntL(),
|
|
0x2 => tim.*[0].cnt.raw,
|
|
0x4 => tim.*[1].getCntL(),
|
|
0x6 => tim.*[1].cnt.raw,
|
|
0x8 => tim.*[2].getCntL(),
|
|
0xA => tim.*[2].cnt.raw,
|
|
0xC => tim.*[3].getCntL(),
|
|
0xE => tim.*[3].cnt.raw,
|
|
else => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, addr }),
|
|
},
|
|
u8 => util.io.read.undef(T, log, "Tried to perform a {} read to 0x{X:0>8}", .{ T, addr }),
|
|
else => @compileError("TIM: Unsupported read width"),
|
|
};
|
|
}
|
|
|
|
pub fn write(comptime T: type, tim: *TimerTuple, addr: u32, value: T) void {
|
|
const nybble = @truncate(u4, addr);
|
|
|
|
return switch (T) {
|
|
u32 => switch (nybble) {
|
|
0x0 => tim.*[0].setCnt(value),
|
|
0x4 => tim.*[1].setCnt(value),
|
|
0x8 => tim.*[2].setCnt(value),
|
|
0xC => tim.*[3].setCnt(value),
|
|
else => util.io.write.undef(log, "Tried to write 0x{X:0>8}{} to 0x{X:0>8}", .{ value, T, addr }),
|
|
},
|
|
u16 => switch (nybble) {
|
|
0x0 => tim.*[0].setCntL(value),
|
|
0x2 => tim.*[0].setCntH(value),
|
|
0x4 => tim.*[1].setCntL(value),
|
|
0x6 => tim.*[1].setCntH(value),
|
|
0x8 => tim.*[2].setCntL(value),
|
|
0xA => tim.*[2].setCntH(value),
|
|
0xC => tim.*[3].setCntL(value),
|
|
0xE => tim.*[3].setCntH(value),
|
|
else => util.io.write.undef(log, "Tried to write 0x{X:0>4}{} to 0x{X:0>8}", .{ value, T, addr }),
|
|
},
|
|
u8 => util.io.write.undef(log, "Tried to write 0x{X:0>2}{} to 0x{X:0>8}", .{ value, T, addr }),
|
|
else => @compileError("TIM: Unsupported write width"),
|
|
};
|
|
}
|
|
|
|
fn Timer(comptime id: u2) type {
|
|
return struct {
|
|
const Self = @This();
|
|
|
|
/// Read Only, Internal. Please use self.getCntL()
|
|
_counter: u16,
|
|
|
|
/// Write Only, Internal. Please use self.setCntL()
|
|
_reload: u16,
|
|
|
|
/// Write Only, Internal. Please use self.setCntH()
|
|
cnt: TimerControl,
|
|
|
|
/// Internal.
|
|
sched: *Scheduler,
|
|
|
|
/// Internal
|
|
_start_timestamp: u64,
|
|
|
|
pub fn init(sched: *Scheduler) Self {
|
|
return .{
|
|
._reload = 0,
|
|
._counter = 0,
|
|
.cnt = .{ .raw = 0x0000 },
|
|
.sched = sched,
|
|
._start_timestamp = 0,
|
|
};
|
|
}
|
|
|
|
/// TIMCNT_L
|
|
pub fn getCntL(self: *const Self) u16 {
|
|
if (self.cnt.cascade.read() or !self.cnt.enabled.read()) return self._counter;
|
|
|
|
return self._counter +% @truncate(u16, (self.sched.now() - self._start_timestamp) / self.frequency());
|
|
}
|
|
|
|
/// TIMCNT_L
|
|
pub fn setCntL(self: *Self, halfword: u16) void {
|
|
self._reload = halfword;
|
|
}
|
|
|
|
/// TIMCNT_L & TIMCNT_H
|
|
pub fn setCnt(self: *Self, word: u32) void {
|
|
self.setCntL(@truncate(u16, word));
|
|
self.setCntH(@truncate(u16, word >> 16));
|
|
}
|
|
|
|
/// TIMCNT_H
|
|
pub fn setCntH(self: *Self, halfword: u16) void {
|
|
const new = TimerControl{ .raw = halfword };
|
|
|
|
// If Timer happens to be enabled, It will either be resheduled or disabled
|
|
self.sched.removeScheduledEvent(.{ .TimerOverflow = id });
|
|
|
|
if (self.cnt.enabled.read() and (new.cascade.read() or !new.enabled.read())) {
|
|
// Either through the cascade bit or the enable bit, the timer has effectively been disabled
|
|
// The Counter should hold whatever value it should have been at when it was disabled
|
|
self._counter +%= @truncate(u16, (self.sched.now() - self._start_timestamp) / self.frequency());
|
|
}
|
|
|
|
// The counter is only reloaded on the rising edge of the enable bit
|
|
if (!self.cnt.enabled.read() and new.enabled.read()) self._counter = self._reload;
|
|
|
|
// If Timer is enabled and we're not cascading, we need to schedule an overflow event
|
|
if (new.enabled.read() and !new.cascade.read()) self.scheduleOverflow(0);
|
|
|
|
self.cnt.raw = halfword;
|
|
}
|
|
|
|
pub fn handleOverflow(self: *Self, cpu: *Arm7tdmi, late: u64) void {
|
|
// Fire IRQ if enabled
|
|
const io = &cpu.bus.io;
|
|
|
|
if (self.cnt.irq.read()) {
|
|
switch (id) {
|
|
0 => io.irq.tim0.set(),
|
|
1 => io.irq.tim1.set(),
|
|
2 => io.irq.tim2.set(),
|
|
3 => io.irq.tim3.set(),
|
|
}
|
|
|
|
cpu.handleInterrupt();
|
|
}
|
|
|
|
// DMA Sound Things
|
|
if (id == 0 or id == 1) {
|
|
cpu.bus.apu.handleTimerOverflow(cpu, id);
|
|
}
|
|
|
|
// Perform Cascade Behaviour
|
|
switch (id) {
|
|
0 => if (cpu.bus.tim[1].cnt.cascade.read()) {
|
|
cpu.bus.tim[1]._counter +%= 1;
|
|
if (cpu.bus.tim[1]._counter == 0) cpu.bus.tim[1].handleOverflow(cpu, late);
|
|
},
|
|
1 => if (cpu.bus.tim[2].cnt.cascade.read()) {
|
|
cpu.bus.tim[2]._counter +%= 1;
|
|
if (cpu.bus.tim[2]._counter == 0) cpu.bus.tim[2].handleOverflow(cpu, late);
|
|
},
|
|
2 => if (cpu.bus.tim[3].cnt.cascade.read()) {
|
|
cpu.bus.tim[3]._counter +%= 1;
|
|
if (cpu.bus.tim[3]._counter == 0) cpu.bus.tim[3].handleOverflow(cpu, late);
|
|
},
|
|
3 => {}, // There is no Timer for TIM3 to "cascade" to,
|
|
}
|
|
|
|
// Reschedule Timer if we're not cascading
|
|
if (!self.cnt.cascade.read()) {
|
|
self._counter = self._reload;
|
|
self.scheduleOverflow(late);
|
|
}
|
|
}
|
|
|
|
fn scheduleOverflow(self: *Self, late: u64) void {
|
|
const when = (@as(u64, 0x10000) - self._counter) * self.frequency();
|
|
|
|
self._start_timestamp = self.sched.now();
|
|
self.sched.push(.{ .TimerOverflow = id }, when -| late);
|
|
}
|
|
|
|
fn frequency(self: *const Self) u16 {
|
|
return switch (self.cnt.frequency.read()) {
|
|
0 => 1,
|
|
1 => 64,
|
|
2 => 256,
|
|
3 => 1024,
|
|
};
|
|
}
|
|
};
|
|
}
|