Compiler/virtual machine interpreter: Difference between revisions

<!--<lang Phix>(notonline)-->

-- demo\rosetta\Compiler\vm.exw

-- ============================

--

-- Since we have generated executable machine code, the virtual machine, such as it is, is just

-- the higher level implementations of printc/i/s, see setbuiltins() in cgen.e

-- Otherwise the only difference between this and cgen.exw is call(code_mem) instead of decode().

--

-- A quick test (calculating fib(44) 10^6 times) suggests ~500 times faster than interp.exw -

-- which is to be expected given that a single add instruction (1 clock) here is implemented as

-- at least three (and quite possibly five!) resursive calls to interp() in the other.</span>

<span style="color: #000080;font-style:italic;">--format ELF32

-- Note: cgen generates 32-bit machine code, which cannot be executed directly from a 64-bit interpreter.

-- You can however, via the magic of either the above format directives, use a 64-bit version of

-- Phix to compile this (just add a -c command line option) to a 32-bit executable, which can.

-- It would not be particularly difficult to emit 32 or 64 bit code, but some source code files

-- would, fairly obviously, then be very nearly twice as long, and a fair bit harder to read.</span>