MASM FOR FUN - REBORN - #0 Extract low order bytes from dwords

[frktons]

So the complete test for greater, less than or equal should
be something like this:

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        pcmpgtd   xmm0,xmm1
pmovmskb eax,xmm0
        .if bit ax, 15
            jmp IsGreater
        .endif

pcmpgtd xmm2,xmm3; same values in reverse order
pmovmskb ebx,xmm2
        .if bit bx, 15
            jmp IsLessThan
        .endif
        .if ax == bx
            jmp AreEqual
        .elseif ax > bx
            jmp IsGreater
        .else
            jmp IsLessThan
        .endif


I'll try the code and let you know.

[nidud]

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[frktons]

Read again my last posts, yes we can know if the
compare gives GT, LT or EQ.

[nidud]

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[nidud]

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[nidud]

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[frktons]

my test for atol:

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Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz (SSE4)
--------------------------------------------------------
429117  cycles for atol LODSB
350976  cycles for atol SHL
411231  cycles for atol LEA
--------------------------------------------------------
430242  cycles for atol LODSB
509282  cycles for atol SHL
395102  cycles for atol LEA
--------------------------------------------------------


well they are a bit random, as you said.

[frktons]

Memcpy:

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Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz (SSE4)
--------------------------------------------------------
757223  cycles for memcpy A
288975  cycles for memcpy movdqa xmm0 A
1352024 cycles for memcpy movdqu xmm0 A
1367569 cycles for memcpy movdqu xmm0..xmm7 A
5668726 cycles for memcpy movdqu xmm0 U
4563076 cycles for memcpy movdqu xmm0..xmm7 U
--------------------------------------------------------
749649  cycles for memcpy A
302916  cycles for memcpy movdqa xmm0 A
1737163 cycles for memcpy movdqu xmm0 A
1841807 cycles for memcpy movdqu xmm0..xmm7 A
6136384 cycles for memcpy movdqu xmm0 U
4055501 cycles for memcpy movdqu xmm0..xmm7 U
--------------------------------------------------------


and the last routines:

Code Select Expand


Intel(R) Core(TM)2 CPU          6600  @ 2.40GHz (SSE4)
--------------------------------------------------------
5825483 cycles for crt_memcpy A
7352188 cycles for memcpy A
7269901 cycles for memcpyd A
4146083 cycles for memcpy movdqa A
8700368 cycles for memcpy movdqu A
27212513        cycles for memcpy movdqu U
--------------------------------------------------------
6180618 cycles for crt_memcpy A
9100718 cycles for memcpy A
7028934 cycles for memcpyd A
4151090 cycles for memcpy movdqa A
11923657        cycles for memcpy movdqu A
29665081        cycles for memcpy movdqu U
--------------------------------------------------------


[frktons]

You could find interesting the test we did a couple of years ago:

[nidud]

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[jj2007]

memcpy?? Looks familiar

[nidud]

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[frktons]

We either all use the same CPU or stick to the basic then  :lol:

Optimization is quite a strange beast indeed, it comes and goes
depending on many [maybe too many] factors.
Nevertheless we can try and find something that we didn't expect :lol:

[jj2007]

Intel(R) Core(TM) i3 CPU         540  @ 3.07GHz (SSE4)
6.065.640       cycles for RtlZeroMemory
5.992.196       cycles for rep stosd
7.240.756       cycles for MOVNTDQ

It seems Intel is still working on rep stosd..!

[GabrielRavier]

I tried it for fun (haven't even read messages here though so this is prolly bad code) :