Lisp Sucks In Assembly

[Brought here from LispSucks, since that page already had more clutter than it needed...]

Don't you mean "at assembly"? And isn't an editorial comment to that effect called for? We may have a variety of reactions to the asm below; it doesn't entirely speak for itself.

Negative. This page was abstracted from the original LispSucks page and brought here just to keep the yards of assembly listings out of the main stream of ThreadMode conversation (read, bickering). Therefore, "Lisp sucks, in assembly."

This still isn't clear English, even given your explanation. This amounts to something like "Lisp sucks: assembly examined" or some such?

Not really. It could have been, "Lisp sucks, in Swedish" or "Lisp sucks, in Klingon" but it's in assembly. Eh?

Isn't blazing fast? I guess you aren't talking about CommonLisp then.

I agree that Lisp is faster than most of the popular languages today - JavaLanguage and PythonLanguage. I was really only talking about CeeLanguage and CeePlusPlus, which are still the dominant languages for programming things like servers and large GUI based applications. It's worth pointing out that in both of those cases it has been found useful to embed Lisp in the program.

For my own code, which tends to be highly numeric and nothing like business apps, I usually find Lisp to range around +- 20% of c++ (yes, sometimes it is faster). Sometimes, however I findit is a factor of 2-5 slower on the same code where c++ had a particularly clever optimization I can't get my lisp compiler to make. On the other hand, sometimes my lisp is a factor of 2-5 faster, if I implement an algorithmic improvement which is simply too much trouble in c++. Of course, YourMileageMayVary, but I would expect that raw execution speed is almost never a compelling argument for c++ over CL, for 'normal' applications. I myself touch on some applications (large-scale simulations) where raw execution speed is crucial, but in that case you run on special hardware and expect to jump through many hoops to get that speed, including things like re-implementing in fortran or c++ with compiler-specific extensions etc. Large server apps may have similar constraints, but we are hardly talking about mainstream development now.

ComputerLanguageBenchmarksGame

Without exception, every proprietary Lisp implementation on the market has a native compiler that puts out good machine code and respects optimizing declarations. And some free ones do also.

Some Lisps, like Conan Lisp, do not even contain an interpreter! Every expression processed by Conan Lisp is converted into 80x86 machine code and then executed as such.

And many Lisps are not afraid to get you close to the metal. The disassemble function is a nice example (this is in CMUCL):

 * (defun sum (n) (loop for i from 1 to n sum i))

 SUM
 * (sum 5)

 15

PJB: how convenient an example. Rather, try: (sum 5000000000). See also: https://groups.google.com/forum/message/raw?msg=comp.lang.lisp/a36NKUYogvI/KWBtYkb-SXoJ (compare Lisp and C with factorial instead of sum).

 * (disassemble #'sum)
 Compiling LAMBDA (N): 
 Compiling Top-Level Form: 

 48131B90:.ENTRY "LAMBDA (N)"(n); (FUNCTION (T) NUMBER)
 BA8:POPDWORD PTR [EBP-8]
 BAB:LEAESP, [EBP-32]
 BAE:MOVEDI, EDX

 BB0:CMPECX, 4
 BB3:JNEL2
 BB5:MOV[EBP-12], EDI
 BB8:MOVDWORD PTR [EBP-16], 4  ; No-arg-parsing entry point
 BBF:MOVDWORD PTR [EBP-20], 0
 BC6:JMPL1
 BC8: L0:MOVEDX, [EBP-20]
 BCB:MOVEDI, [EBP-16]
 BCE:CALL  #x100001C8
 BD3:MOVESP, EBX
 BD5:MOV[EBP-20], EDX
 BD8:MOVEDX, [EBP-16]
 BDB:MOVEDI, 4

 BE0:CALL  #x100001C8
 BE5:MOVESP, EBX
 BE7:MOV[EBP-16], EDX
 BEA: L1:MOVEDX, [EBP-16]
 BED:MOVEDI, [EBP-12]

 ;;; [4] (LOOP FOR I FROM ...)

 BF0:CALL  #x10000460
 BF5:MOVESP, EBX
 BF7:CMPEDX, #x2800000B; NIL
 BFD:JEQL0
 BFF:MOVEDX, [EBP-20]
 C02:MOVECX, [EBP-8]
 C05:MOVEAX, [EBP-4]
 C08:ADDECX, 2
 C0B:MOVESP, EBP
 C0D:MOVEBP, EAX
 C0F:JMPECX
 C11:NOP

 C12:NOP
 C13:NOP
 C14:NOP
 C15:NOP
 C16:NOP
 C17:NOP
 C18: L2:BREAK 10; Error trap
 C1A:BYTE  #x02
 C1B:BYTE  #x19; INVALID-ARGUMENT-COUNT-ERROR
 C1C:BYTE  #x4D; ECX

Note that disassemble is a standard feature. Here's how it works in CLISP, a bytecode-interpreting implementation:

 [1]> (defun sum (n) (loop for i from 1 to n sum i))
 SUM
 [2]> (disassemble #'sum)

 Disassembly of function SUM
 (CONST 0) = 0
 (CONST 1) = 1
 1 required arguments
 0 optional arguments
 No rest parameter
 No keyword parameters
 0(CONST&PUSH 0); 0
 1(CONST&PUSH 1); 1
 2(JMP L12)
 4L4
 4(LOAD&PUSH 1)
 5(LOAD&PUSH 1)
 6(CALLSR&STORE 2 54 1); +
 10(LOAD&INC&STORE 0)
 12L12
 12(LOAD&PUSH 0)
 13(LOAD&PUSH 4)
 14(CALLSR&JMPIFNOT 1 49 L4); >
 18(LOAD 1)
 19(SKIP&RET 4)
 #<COMPILED-CLOSURE SUM>

CommonLisp ain't for QuicheEaters?!

By the way, if anyone's looking at the disassembled x86 machine code for the SUM function above and thinking "yeccch, that's ten times worse than it would be in C", here's what you get if you throw in some type declarations (like you need all the time in C) and tell the compiler to prefer speed over safety (like you get all the time in C).

 48081060:.ENTRY SUM(n); (FUNCTION (FIXNUM) FIXNUM)
 78:POPDWORD PTR [EBP-8]
 7B:LEAESP, [EBP-32]
 7E:MOVEAX, 4 ; No-arg-parsing entry point
 83:XORECX, ECX
 85:JMPL1
 87: L0:ADDECX, EAX
 89:ADDEAX, 4
 8C: L1:CMPEAX, EDX
 8E:JLEL0
 90:MOVEDX, ECX
 92:MOVECX, [EBP-8]
 95:MOVEAX, [EBP-4]
 98:ADDECX, 2
 9B:MOVESP, EBP
 9D:MOVEBP, EAX
 9F:JMPECX
 A1:NOP
 A2:NOP
 A3:NOP
 A4:NOP

 ;;; [7] (LOOP FOR I FIXNUM ...)

 A5:NOP
 A6:NOP
 A7:NOP

Of course, a really smart compiler could produce

 480C65D0:.ENTRY SUM(n); (FUNCTION (FIXNUM)
  (SIGNED-BYTE 29))
 5E8:POPDWORD PTR [EBP-8]
 5EB:LEAESP, [EBP-32]
 5EE:LEAEAX, [EDX+4]; No-arg-parsing entry point
 5F1:SAREDX, 2
 5F4:IMUL  EDX, EAX
 5F7:SAREDX, 1
 5F9:ANDEDX, 4294967292
 5FF:MOVECX, [EBP-8]
 602:MOVEAX, [EBP-4]
 605:ADDECX, 2
 608:MOVESP, EBP
 60A:MOVEBP, EAX

 60C:JMPECX
 60E:NOP
 60F:NOP

instead ...

I saw the title and initially envisioned something that looked like this :-)

 (EAX (JMP (SAR EPX NOP) ESP LEA) MOV (ADD EBP)) JLE EBP)

CategorySucks CategoryLisp