Hi, I happened to look at some C# code today disassembled into .NET IL “byte code” – which reminded me that SWI-Prolog also has its byte code and (WAM) VM. I am curious – how do these compare in practice in terms of performance. Question is also applicable to Java byte code and VM. I guess all th…

[image] grossdan: SWI-Prolog also has its byte code and (WAM) VM. AFAIK SWI-Prolog is implemented with C, there is no IL, it does not use WAM.

Thanks. I mean, swi-prolog programs are translated into byte code and executed through a WAM VM Dan

I started searching the source at GitHub and found pl-wam.c so now I have to question my own reply.

There is also the command: vm_list(Predicate_name)

The keyword I use to search the SWI-Prolog source code for where the Prolog predicates are implemented in C is PRED_IMPL The way I think of the code is that what can be done with Prolog is done in Prolog, the low level actions such as unification are done in C. Then if a predicate needs to be faste…

What confuses me is that if I use vm_list/1 on unification (=) ?- vm_list(=). ======================================================================== =/2 ======================================================================== 0 i_fopen 1 i_fcalldetva(4611685623215523968) 3 i_fexitdet tru…

[image] EricGT: The way I think of the code is that what can be done with Prolog is done in Prolog, the low level actions such as unification are done in C. Then if a predicate needs to be faster it is done with calls straight into C. Sometimes, as Jan notes, the code is so tricky that it is be…

[image] EricGT: So what is the relationship between vm_list/1 , the source files pl-wam.c pl-vmi.c and the implementation of the predicates using PRED_IMPL ? When I look at the instructions for the WAM, e.g. unify_value I would expect to see them in the result from vm_list(=) . So what is vm_lis…

Hi, Thank you for the information. So, it seems that Prolog would, for an equivalent task be quite slower – speed is mostly gained by those predicates that executed in compiled C. And my assumption that VMs are inherently slower than native code is not really true … once just in time compiled the…

[image] grossdan: So, it seems that Prolog would, for an equivalent task be quite slower – speed is mostly gained by those predicates that executed in compiled C. The granularity of most of the Prolog VM instructions is a lot higher, meaning a single instruction does far more work than it wou…

Curious: How does Prolog "Byte code" compare to .NET IL (and some thoughts about enterprise ready systems)

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Curious: How does Prolog "Byte code" compare to .NET IL (and some thoughts about enterprise ready systems)

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