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doc(emu): properly document + simply constants

This commit is contained in:
Rekai Nyangadzayi Musuka 2022-10-28 21:57:30 -03:00
parent 14b24787ab
commit 4eb715a138
1 changed files with 14 additions and 10 deletions
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24
src/core/emu.zig
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@ -9,18 +9,22 @@ const FpsTracker = @import("../util.zig").FpsTracker;
const Timer = std.time.Timer;
const Atomic = std.atomic.Atomic;
// 228 Lines which consist of 308 dots (which are 4 cycles long)
const cycles_per_frame: u64 = 228 * (308 * 4); //280896
const clock_rate: u64 = 1 << 24; // 16.78MHz
/// 4 Cycles in 1 dot
const cycles_per_dot = 4;
// TODO: Don't truncate this, be more accurate w/ timing
// 59.6046447754ns (truncated to just 59ns)
const clock_period: u64 = std.time.ns_per_s / clock_rate;
const frame_period = (clock_period * cycles_per_frame);
/// The GBA draws 228 Horizontal which each consist 308 dots
/// (note: not all lines are visible)
const cycles_per_frame = 228 * (308 * cycles_per_dot); //280896
// 59.7275005696Hz
pub const frame_rate = @intToFloat(f64, std.time.ns_per_s) /
((@intToFloat(f64, std.time.ns_per_s) / @intToFloat(f64, clock_rate)) * @intToFloat(f64, cycles_per_frame));
/// The GBA ARM7TDMI runs at 2^24 Hz
const clock_rate = 1 << 24; // 16.78MHz
/// The # of nanoseconds a frame should take
const frame_period = (std.time.ns_per_s * cycles_per_frame) / clock_rate;
/// Exact Value: 59.7275005696Hz
/// The inverse of the frame period
pub const frame_rate: f64 = @intToFloat(f64, clock_rate) / cycles_per_frame;
const log = std.log.scoped(.Emulation);