Using a magic multiplier (http://www.hackersdelight.org/magic.htm) used to be the trick to avoid slow division. It works fine, but my tests say that the advantage is small, especially if the numbers are small. DivBy10 is a macro that divides the argument passed by 10. The result is in edx.
Intel(R) Core(TM) i5-2450M CPU @ 2.50GHz
450 ms for DivBy10, Rand(-1)
1108 ms for idiv
391 ms for DivBy10, Rand(2000000000)
553 ms for idiv
399 ms for DivBy10, Rand(20000)
469 ms for idiv
444 ms for DivBy10, Rand(-1)
1059 ms for idiv
350 ms for DivBy10, Rand(2000000000)
474 ms for idiv
390 ms for DivBy10, Rand(20000)
420 ms for idiv
[/code]
I don't know what is in the source as it is not MASM.
Intel(R) Core(TM) i7-5820K CPU @ 3.30GHz
365 ms for DivBy10, Rand(-1)
1018 ms for idiv
295 ms for DivBy10, Rand(2000000000)
420 ms for idiv
300 ms for DivBy10, Rand(20000)
363 ms for idiv
Intel(R) Core(TM) i7-4810MQ CPU @ 2.80GHz
348 ms for DivBy10, Rand(-1)
986 ms for idiv
307 ms for DivBy10, Rand(2000000000)
427 ms for idiv
303 ms for DivBy10, Rand(20000)
388 ms for idiv
Quote from: hutch-- on August 27, 2018, 11:33:34 AM
I don't know what is in the source as it is not MASM.
Inter alia, there is a loop in the source (which opens fine in Wordpad btw):
.Repeat
void Rand(randRange)
cdq
mov esi, 10
idiv esi
inc ecx
.Until ecx>loopsOr did you mean "modern MASM" syntax, as in .Until ecx
}loops? ;)
:biggrin:
You have been flogging that one for a few years now. Now if you are so hostile to anything Microsoft, why are you using Windows and not Unix or Lunix variations ?
Quote
(which opens fine in Wordpad btw)
So now we have WordPad as the ultimate proogramming editor. :P
Humerous how someone who hates Microsoft so desperately clings to a clone of the 1990 version of the Microsoft assembler. How would you handle FASM or GAS in a non Microsoft world, perhaps NASM if you wanted to go multi-port.
Just to make you laugh, I can open it in my RTF help file editor.
include \masm32\MasmBasic\MasmBasic.inc ; download (http://masm32.com/board/index.php?topic=94.0)
DivBy10 MACRO arg
ifdifi <arg>, <eax>
mov eax, arg
endif
mov edx, 3435973837
mul edx
sar edx, 3
ENDM
°B1Init
PrintCpu 0
xor ecx, ecx
loops=100000000
NanoTimer()
.Repeat
DivBy10 Rand(-1)
inc ecx
.Until ecx>loops
PrintLine NanoTimer$(), " for DivBy10, Rand(-1)"
xor ecx, ecx
NanoTimer()
.Repeat
void Rand(-1)
cdq
mov esi, 10
idiv esi
inc ecx
.Until ecx>loops
PrintLine NanoTimer$(), " for idiv", CrLf$
xor ecx, ecx
NanoTimer()
.Repeat
DivBy10 Rand(2000000000)
inc ecx
.Until ecx>loops
PrintLine NanoTimer$(), " for DivBy10, Rand(2000000000)"
xor ecx, ecx
NanoTimer()
.Repeat
void Rand(2000000000)
cdq
mov esi, 10
idiv esi
inc ecx
.Until ecx>loops
PrintLine NanoTimer$(), " for idiv", CrLf$
xor ecx, ecx
NanoTimer()
.Repeat
DivBy10 Rand(20000)
inc ecx
.Until ecx>loops
PrintLine NanoTimer$(), " for DivBy10, Rand(20000)"
xor ecx, ecx
NanoTimer()
.Repeat
void Rand(20000)
cdq
mov esi, 10
idiv esi
inc ecx
.Until ecx>loops
Inkey NanoTimer$(), " for idiv", CrLf$
EndOfCode
°B5RichMasm: Press F6 to assemble & link
Bottom line is REAL MEN[tm] write their loop code in Intel mnemonics, not everyone wants a compiler writer to hold their hot little hand. :biggrin:
Now the question is, where is your modern 64 bit /LARGEADDRESSAWARE code ?
Psssssst, I should have mentioned, as the code you posted is 32 bit, have you confused 32 and 64 bit MASM ?
32 bit MASM (ML.EXE) runtime comparison operators.
Operator Meaning
== Equal
!= Not equal
> Greater than
>= Greater than or equal to
< Less than
<= Less than or equal to
& Bit test (format: expression & bitnumber)
! Logical NOT
&& Logical AND
|| Logical OR
CARRY? Carry bit set
OVERFLOW? Overflow bit set
PARITY? Parity bit set
SIGN? Sign bit set
ZERO? Zero bit set
Is this the daily portion of Spam Basic?
I have a very pragmatic view about using Microsoft's tool set. Every time I buy a new retail OS version it costs me a small fortune and while most of their apps are crap, the tool set works OK and I have used versions of them since the DOS days so I make sure I get what I pay for by using their tool set on an OS that I have paid for.
Now while I have nothing against anyone using anything they like, OCR of granite inscriptions are OK by me, I don't intend to have anyone else's view imposed on me as I choose to use what I pay for. The "Open Sauce" guys are fine doing their own thing and while most of it ends up as a pile of sh*t dumped to die somewhere, they are all big kids now.
What I don't grasp is anyone who so desperately hates Microsoft buying Windows when they can get their own copy of an "Open Sauce" OS for free. GAS is a great assembler if you use the Intel rather than AT&T notation you could almost look like MASM. :P
Quote from: AW on August 28, 2018, 01:03:12 AM
Is this the daily portion of Spam Basic?
No, it's the daily portion of "nobody holds your hot little hand" 8)
Quote from: hutch-- on August 28, 2018, 02:20:34 AMWhat I don't grasp is anyone who so desperately hates Microsoft buying Windows
Linux is worse. Which doesn't stop me from solemnly declaring that
.if eax}edx causes eye cancer :badgrin:
> Linux is worse. Which doesn't stop me from solemnly declaring that .if eax}edx causes eye cancer
If that is all that is stopping you from writing 64 bit, do it like REAL MEN[tm] with mnemonics.
cmp rax, rdx
je label