why:
on 32bit windows 7, there seems to be a 64k memory ceiling for the gcc
compiler which was exceeded on some test platform.
details:
compiling VM2 for low memory C compiler can be triggered with
"make ENABLE_VM2LOWMEM". this comes with a ~24% longer execution time
of the test suite against old VM and optimised VM2.
why:
the new implementation lost more then 25% execution time on the test
suite when compared to the original VM. so the handler call and the
surrounding statements have been wrapped in a big case statement similar
to the original VM implementation. on Linux/x64, the execution time of
the new VM2 seems to be on par with the old VM.
details:
on Linux/x64, computed goto works and is activated with the -d:release
flag. here the execution time of the new VM2 was tested short of 0.02%
better than the old VM. without the computed goto, it is short of
0.4% slower than the old VM.
why:
using function stubs made it possible to check the syntax of an op
handler source file by compiling this very file. this was previously
impossible due cyclic import/include mechanism.
details:
only oph_call.nim, oph_create.nim and subsequently op_handlers.nim
still need the -d:kludge:1 flag for syntax check compiling. this flag
also works with interpreter_dispatch.nim which imports op_handlers.nim.
why:
step towards breaking circular dependency
details:
some functions from v2computation.nim have been extracted into
compu_helper.nim which does not explicitly back-import
v2computation.nim. all non recursive op handlers now import this source
file rather than v2computation.nim.
recursive call/create op handler still need to import v2computation.nim.
the executeOpcodes() function from interpreter_dispatch.nim has been
moved to v2computation.nim which allows for <import> rather than
<include> the interpreter_dispatch.nim source.
why:
this allows for passing back information which can eventually be
used for reducing use of exceptions
caveat:
call/create currently needs to un-capture the call-by-reference
(wrapper) argument using the Computation reference inside
why:
these files provide part of the externally accessible interface
provided by vm_message.nim, vm_precompile.nim, vm_gas_cost.nim. so the
new filename indicates that the source code belongs to vm2 (rather
than vm).
why:
these files provide part of the externally accessible interface
provided by vm_types*.nim. so the new filename indicates that the
source code belongs to vm2 (rather than vm).
why:
vm2 enabled by ENABLE_VM2=1 behaves as vm without ENABLE_EVMC=1 until
it doesn't in some future fatch set. this leaves some wiggle room
to work on a vm copy without degrading the original implementation.
details:
+ additional make flag ENABLE_VM2=1 (or ENABLE_VM2=0 to explicitely disable)
+ when both flags ENABLE_EVMC=1 and ENABLE_VM2=1 are present, the former
flag ENABLE_EVMC=1 takes precedence, this is implemented at the NIM
compiler level for -d:evmc_enabled and -d:vm2_enabled
Jordan Hrycaj