Re: clock cycle values AMD manual
- From: "Wolfgang Kern" <spamtrap@xxxxxxxxxx>
- Date: Sun, 18 May 2008 11:27:11 +0200
"roger21" asked:
just a newb question : where do i get the length of each instruction or
at last the number of clock cycle for each instruction in the amd docs ?
Most instructions got a variable length depending on involved
operands and addressing mode. That's why you only see
ie: MOV r,r/m |MOV r/m,r |and similar ...
use32: ;btw: almost equal timing for this three
01 07 add [edi],eax ;2 byte
01 47 55 add [edi+55h],eax ;3 byte
01 87 55 66 77 88 add [edi+88776655h],eax ;6 byte
....
use16: ;this seem to be the largest possible:
F0 65 66 67 81 84 87 10 20 30 40 50 60 70 80
LOCK ADD dword GS:[edi+eax*4+40302010h],80706050h ;15 byte
Exact calculation of code duration is a nightmare and almost
impossible on modern x86, it just depends on too many things.
But a rough estimation can be done with the latency/throughput
values found in "AMD Software Optimisation Guide"(s),
25412.pdf 24594.pdf and perhaps more.
__
wolfgang
.
- References:
- clock cycle values AMD manual
- From: roger21
- clock cycle values AMD manual
- Prev by Date: Re: clock cycle values AMD manual
- Next by Date: Re: 640x512x16bpp with VESA ?
- Previous by thread: Re: clock cycle values AMD manual
- Next by thread: linuxassembly (italian book) I will not allow more than follow the work.
- Index(es):
Relevant Pages
|
