[ANN] VM Version 10.0.0 Release

We have released a new version of the Pharo VM for Pharo 11. This VM is accessible right now from Zero-Conf, updating it in the Pharo Launcher or using the usual downloads (as described in pharo.org/download). OBS packages are still in work and will come later.

This is the new VM that will be stable for Pharo 11 release, it is also compatible with Pharo 10 images but it is not the default for Pharo 10.

It has a lot of changes and improvements, as it is the result of more than a year and a half of improvements, clean-ups, and bug fixes.

Changelog v10.0.0:

Slang (Smalltalk to C Translator)

  • Introducing a C AST to ease the generation of C Code
  • Having a Pretty Printer for C AST
  • Translation Tests
  • Fixing Translation Issues
  • Clear separation between Slang and VM code
  • Improving Cast generation

Clean Up:

  • Remove Old Bytecode Set
  • Remove Old Block Implementation
  • Simplification of the Primitives
  • Removing Unused / Old Code / Dead Code
  • Cleanup / Removal of Old Unused primitives
  • Removing Old FFI Implementation
  • Removing MT Experiment from the code base (Kept in own branch)
  • Fixing Compilation Warnings
  • Improving Type annotations to fix bugs in the translation / compilation
  • Removing Conditional Code on Old Configurations / Features
  • Renaming Concepts to be inline with Common terminology
  • Remove Newspeak, Multiple Bytecode and Old Memory Managers
  • Removing Unused Plugins


  • GNUification Tests
  • Tests for Math primitives including overflow and conversion testing.
  • Tests for comparison primitives (Equals / Not Equals / Less than / Less or Equals / Greater Than / Greater or Equals)
  • Testing Primitives for objects Pinned in Memory
  • Testing Math Primitives for Immediate Classes (SmallFloats / SmallIntegers)
  • Improving Simulation Infrastructure
  • Using Sista Bytecode in all Tests
  • Updating Unicorn version
  • Improving Machine Code emulation
  • Testing Image Read / Image Write
  • Using the same memory map in Tests and Execution
  • Testing Ephemerons
  • Become Primitives


  • Fix for large amounts
  • Make it available
  • Testing Signal Finalizations

Single-Instruction Multiple-Data (SIMD) initial Support:

  • Initialization of new objects using SIMD (ARM64)
  • Adding Bytecode Extensions to support SIMD instructions
  • Adding Vector Registers
  • Vector Register bytecodes


  • Fixing Become Errors.
  • Fixing XRay Primitive
  • Auto Localization of Interpreter loop variables and edge detection simplifying development and minimizing code
  • ImageReader / ImageWriter reification needed for Permanent Space.
  • Improving Memory Map of the VM (Using constant positions)
  • Dependencies Improvements
3 March 2023