JAR: JAM Axiomatic Reference

10.2. Host Calls (§12.4)🔗

All 27 host-call handlers (indices 0–26) are dispatched by handleHostCall. Each host call costs a base gas of 10. Operations include reading/writing service storage, transferring balance, managing preimages, and creating or upgrading services.

🔗def
Jar.Accumulation.handleHostCall [Jar.JamConfig] (callId : Jar.PVM.Reg)
  (gas : Jar.Gas) (regs : Jar.PVM.Registers) (mem : Jar.PVM.Memory)
  (ctx : AccContext) : Jar.PVM.InvocationResult × AccContext
Jar.Accumulation.handleHostCall
  [Jar.JamConfig] (callId : Jar.PVM.Reg)
  (gas : Jar.Gas)
  (regs : Jar.PVM.Registers)
  (mem : Jar.PVM.Memory)
  (ctx : AccContext) :
  Jar.PVM.InvocationResult × AccContext

Dispatch a host call during accumulation. GP §12, Appendix B. Returns updated invocation result and context.