Release 1.7.0

BENCHMARK.md

@@ -26,8 +26,8 @@ bundle exec ruby --yjit -Ilib exe/rubyboy-bench \
 
 Each trial starts with a fresh emulator and runs the CPU, timer, PPU and APU
 without input, saves, drawing, audio output or real-time synchronization.
-The command prints each trial's duration and the aggregate FPS (total measured
-frames divided by total measured time).
+The command prints each trial's duration, the aggregate FPS (total measured
+frames divided by total measured time) and a checksum of the final frame.
 
 ## Spinel
 
@@ -49,14 +49,20 @@ runtime. Use a warmup so that YJIT has compiled the hot code before measurement.
 Record the Ruby version (`ruby -v`) or Spinel revision (`spinel --version`) and the
 Rubyboy revision with each result.
 
+The checksum depends only on the ROM and the total of `--warmup-frames` and `--frames`,
+so every runtime must print the same value. A different value means that runtime
+emulated incorrectly. For example, with the bundled ROM, `--frames 600 --count 1`
+prints `Checksum: 661048662`.
+
 ## Results
 
-Measured on 2026-10-10 with Rubyboy `3484036` on a MacBook Air (Apple M4, macOS 15.5)
+Measured on 2026-10-10 with Rubyboy 1.7.0 (`44f834f`) on a MacBook Air (Apple M4, macOS 15.5)
 on AC power with other applications closed, using the commands above
 (`tobu.gb`, `--frames 1500 --warmup-frames 1500 --count 5`).
+All three printed `Checksum: 3889316277`.
 
 | Runtime | Version | FPS |
 | --- | --- | ---: |
-| CRuby | 4.0.7 | 114 |
-| CRuby + YJIT | 4.0.7 | 297 |
-| Spinel (native) | `2810a23` | 603 |
+| CRuby | 4.0.7 | 113 |
+| CRuby + YJIT | 4.0.7 | 294 |
+| Spinel (native) | `7d999f50c` | 799 |

CHANGELOG.md

@@ -1,9 +1,11 @@
-## [Unreleased]
+## [1.7.0] - 2026-10-10
 
 - Require Ruby 4.0 or higher
 - Keep audio output with --unlimited by dropping audio that cannot be played in time
 - Remove the --no-audio player option
 - Remove rubyboy-bench --render and --json, and the SDL 2.0.18 requirement
+- Print a checksum of the final frame from rubyboy-bench to check that a runtime emulated correctly
+- Run rubyboy-bench without loading SDL
 - Run the bundled Tobu Tobu Girl ROM when rubyboy or rubyboy-bench gets no ROM path, from any directory
 - Read ROM files in binary mode, which fixes loading them on Windows
 - Make the APU duty tables shareable between Ractors

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    rubyboy (1.6.0)
+    rubyboy (1.7.0)
       ffi (~> 1.16, >= 1.16.3)
 
 GEM

README.md

@@ -55,8 +55,8 @@ next to the ROM file.
 
 ## Benchmark
 
-On an Apple M4, Rubyboy runs at about 110 FPS on CRuby, 300 FPS with YJIT and
-600 FPS when compiled with Spinel. See [BENCHMARK.md](BENCHMARK.md) for the method and details.
+On an Apple M4, Rubyboy runs at about 110 FPS on CRuby, 290 FPS with YJIT and
+800 FPS when compiled with Spinel. See [BENCHMARK.md](BENCHMARK.md) for the method and details.
 
 ## Other ways to run
 

exe/rubyboy-bench

@@ -1,7 +1,6 @@
 #!/usr/bin/env ruby
 # frozen_string_literal: true
 
-require 'rubyboy'
 require 'bench'
 require 'optparse'
 

lib/bench.rb

@@ -10,6 +10,7 @@ def run(count: 3, frames: 1500, rom_path: Rom::DEFAULT_PATH, warmup_frames: 0)
       validate_integer(:warmup_frames, warmup_frames, 0)
 
       time_sum = 0
+      frame_checksum = 0
       count.times do |i|
         emulator = Rubyboy::EmulatorHeadless.new(rom_path)
         run_frames(emulator, warmup_frames)
@@ -19,9 +20,12 @@ def run(count: 3, frames: 1500, rom_path: Rom::DEFAULT_PATH, warmup_frames: 0)
         puts "#{i + 1}: #{time / 1_000_000_000.0} sec"
 
         time_sum += time
+        frame_checksum = checksum(emulator.framebuffer)
       end
 
       puts "FPS: #{frames * count * 1_000_000_000.0 / time_sum}"
+      # Every trial ends on the same frame. A different value on another runtime means it emulated incorrectly.
+      puts "Checksum: #{frame_checksum}"
     end
 
     private
@@ -33,6 +37,11 @@ def validate_integer(name, value, minimum)
       raise ArgumentError, "#{name} must be #{requirement}"
     end
 
+    # Integer arithmetic only, so CRuby and ahead-of-time compilers such as Spinel produce the same value.
+    def checksum(framebuffer)
+      framebuffer.reduce(0) { |hash, pixel| ((hash * 31) + pixel) & 0xffffffff }
+    end
+
     def run_frames(emulator, frames)
       frame_count = 0
       while frame_count < frames

lib/rubyboy/emulator_headless.rb

@@ -27,6 +27,10 @@ def initialize(rom_path)
       @cpu = Cpu.new(bus, interrupt)
     end
 
+    def framebuffer
+      @ppu.buffer
+    end
+
     def step
       loop do
         cycles = @cpu.exec

lib/rubyboy/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Rubyboy
-  VERSION = '1.6.0'
+  VERSION = '1.7.0'
 end

spec/bench_spec.rb

@@ -5,20 +5,20 @@
 require 'rbconfig'
 
 RSpec.describe Rubyboy::Bench do
-  let(:emulator) { instance_double(Rubyboy::EmulatorHeadless, step: nil) }
+  let(:emulator) { instance_double(Rubyboy::EmulatorHeadless, step: nil, framebuffer: [1, 2]) }
 
   before do
     allow(Rubyboy::EmulatorHeadless).to receive(:new).and_return(emulator)
   end
 
   it 'starts each trial from a fresh emulator, warms up identically, and aggregates measured durations' do
-    second_emulator = instance_double(Rubyboy::EmulatorHeadless, step: nil)
+    second_emulator = instance_double(Rubyboy::EmulatorHeadless, step: nil, framebuffer: [1, 2])
     allow(Rubyboy::EmulatorHeadless).to receive(:new).with('test.gb').and_return(emulator, second_emulator)
     allow(Process).to receive(:clock_gettime).with(Process::CLOCK_MONOTONIC, :nanosecond).and_return(1_000_000_000, 2_000_000_000, 3_000_000_000, 5_000_000_000)
 
     expect do
       described_class.new.run(count: 2, frames: 3, warmup_frames: 2, rom_path: 'test.gb')
-    end.to output("1: 1.0 sec\n2: 2.0 sec\nFPS: 2.0\n").to_stdout
+    end.to output("1: 1.0 sec\n2: 2.0 sec\nFPS: 2.0\nChecksum: 33\n").to_stdout
 
     expect(Rubyboy::EmulatorHeadless).to have_received(:new).with('test.gb').twice
     expect(emulator).to have_received(:step).exactly(5).times
@@ -59,6 +59,13 @@
     expect(stdout).to match(/^FPS: /)
   end
 
+  it 'prints the same checksum of the final frame on every run' do
+    stdout, stderr, status = Open3.capture3(RbConfig.ruby, '-Ilib', 'exe/rubyboy-bench', '--count', '2', '--frames', '60', chdir: repository_root)
+
+    expect(status.success?).to be(true), stderr
+    expect(stdout).to end_with("Checksum: 4059938609\n")
+  end
+
   it 'rejects an invalid count with a failing exit status' do
     _stdout, stderr, status = Open3.capture3(RbConfig.ruby, '-Ilib', 'exe/rubyboy-bench', '--count', '0', chdir: repository_root)