As I know, some processors can make few(for example 2) cycle in one
clock cycles. My tms320c6713 works with 225MHz and my algorithm has
1800 cycles of CPU. So algorithm is created by CPU in (1/225MHz)*1800
? Or maybe in one clock cycle cpu can do 2(or more)machine cycles?
c6713: cpu cycles and clock cycles
Started by ●May 23, 2007
Reply by ●May 25, 20072007-05-25
Nazwa-
> As I know, some processors can make few(for example 2) cycle in one
> clock cycles. My tms320c6713 works with 225MHz and my algorithm has
> 1800 cycles of CPU. So algorithm is created by CPU in (1/225MHz)*1800
> ? Or maybe in one clock cycle cpu can do 2(or more)machine cycles?
You mean "instructions per cycle", right? I think it's widely accepted that a
"cycle" is a clock cycle, so you would not want to get these mixed up.
If your algorithm takes 1800 clock cycles (8 usec), then it's difficult to know the
actual number of instructions. It could take more than 1800 if your asm code is
using parallel instructions (is it?), or it could take less if you're causing the CPU
to stall due to onchip I/O access, or both.
-Jeff
> As I know, some processors can make few(for example 2) cycle in one
> clock cycles. My tms320c6713 works with 225MHz and my algorithm has
> 1800 cycles of CPU. So algorithm is created by CPU in (1/225MHz)*1800
> ? Or maybe in one clock cycle cpu can do 2(or more)machine cycles?
You mean "instructions per cycle", right? I think it's widely accepted that a
"cycle" is a clock cycle, so you would not want to get these mixed up.
If your algorithm takes 1800 clock cycles (8 usec), then it's difficult to know the
actual number of instructions. It could take more than 1800 if your asm code is
using parallel instructions (is it?), or it could take less if you're causing the CPU
to stall due to onchip I/O access, or both.
-Jeff
Reply by ●May 25, 20072007-05-25
Nazwa-
> thanks for answer.
>
> where exacly should i look for answer for question about parallel instruction in asm code? in processor manual?? (i
> use tms320c6713 and dsk c6713)
Well, one thing you can do is enable the build option to "keep" CCS-generated asm files, and look at the asm source in
the CCS editor (the files will have .asm extension). If you see the "||" (double vert bar) then that's a parallel
instruction. Sometimes you might see two in a row, that means three instructions in one clock cycle, for example:
inst 1
|| inst 2
|| inst 3
Examples of these are all over the web and the TI docs, so you won't have trouble finding them.
-Jeff
> ----- Original Message ----
> From: Jeff Brower
> To: Nazwa Uytkownika
> Cc: c...
> Sent: Thursday, May 24, 2007 11:49:44 PM
> Subject: Re: [c6x] c6713: cpu cycles and clock cycles
>
> Nazwa-
>
>> As I know, some processors can make few(for example 2) cycle in one
>> clock cycles. My tms320c6713 works with 225MHz and my algorithm has
>> 1800 cycles of CPU. So algorithm is created by CPU in (1/225MHz)*1800
>> ? Or maybe in one clock cycle cpu can do 2(or more)machine cycles?
>
> You mean "instructions per cycle", right? I think it's widely accepted that a
> "cycle" is a clock cycle, so you would not want to get these mixed up.
>
> If your algorithm takes 1800 clock cycles (8 usec), then it's difficult to know the
> actual number of instructions. It could take more than 1800 if your asm code is
> using parallel instructions (is it?), or it could take less if you're causing the CPU
> to stall due to onchip I/O access, or both.
>
> -Jeff
> thanks for answer.
>
> where exacly should i look for answer for question about parallel instruction in asm code? in processor manual?? (i
> use tms320c6713 and dsk c6713)
Well, one thing you can do is enable the build option to "keep" CCS-generated asm files, and look at the asm source in
the CCS editor (the files will have .asm extension). If you see the "||" (double vert bar) then that's a parallel
instruction. Sometimes you might see two in a row, that means three instructions in one clock cycle, for example:
inst 1
|| inst 2
|| inst 3
Examples of these are all over the web and the TI docs, so you won't have trouble finding them.
-Jeff
> ----- Original Message ----
> From: Jeff Brower
> To: Nazwa Uytkownika
> Cc: c...
> Sent: Thursday, May 24, 2007 11:49:44 PM
> Subject: Re: [c6x] c6713: cpu cycles and clock cycles
>
> Nazwa-
>
>> As I know, some processors can make few(for example 2) cycle in one
>> clock cycles. My tms320c6713 works with 225MHz and my algorithm has
>> 1800 cycles of CPU. So algorithm is created by CPU in (1/225MHz)*1800
>> ? Or maybe in one clock cycle cpu can do 2(or more)machine cycles?
>
> You mean "instructions per cycle", right? I think it's widely accepted that a
> "cycle" is a clock cycle, so you would not want to get these mixed up.
>
> If your algorithm takes 1800 clock cycles (8 usec), then it's difficult to know the
> actual number of instructions. It could take more than 1800 if your asm code is
> using parallel instructions (is it?), or it could take less if you're causing the CPU
> to stall due to onchip I/O access, or both.
>
> -Jeff
