* floating point operation of ppc [not found] <000a01c5e6a0$1eba5150$f10cc9ca@lcj3bdfa4e34dd> @ 2005-11-11 9:13 ` lily 2005-11-11 12:51 ` Greg Weeks 0 siblings, 1 reply; 4+ messages in thread From: lily @ 2005-11-11 9:13 UTC (permalink / raw) To: linuxppc-embedded [-- Attachment #1: Type: text/plain, Size: 543 bytes --] hi,all: i build an embedded linux on powerpc 405ep,i need execute floating point operation,and i enable "math emulate" option in kernel, i run a while(1)loop ,in the loop there was floating point expression ,after test ,i found the while (1) exit because of the floating point computation,that is the floating point can't execute on ppc stablely.Is there someone meets the same problems ,please give me some suggestion,thanks!!! lily [-- Attachment #2: Type: text/html, Size: 1466 bytes --] ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: floating point operation of ppc 2005-11-11 9:13 ` floating point operation of ppc lily @ 2005-11-11 12:51 ` Greg Weeks 2005-11-11 19:35 ` Eugene Surovegin 0 siblings, 1 reply; 4+ messages in thread From: Greg Weeks @ 2005-11-11 12:51 UTC (permalink / raw) To: lily; +Cc: linuxppc-embedded lily wrote: > hi,all: > i build an embedded linux on powerpc 405ep,i need execute floating > point operation,and i enable "math emulate" option in kernel, i run a > while(1)loop ,in the loop there was floating point expression ,after > test ,i found the while (1) exit because of the floating point > computation,that is the floating point can't execute on ppc > stablely.Is there someone meets the same problems ,please give me some > suggestion,thanks!!! The 405ep has some errata on floating point use. I didn't work on the processor so I don't know exactly what they are, but Timesys has a toolchain just for the 405ep to work around the problem. The other workaround we've used is much slower and it involved disabling the hardware floating point unit in the head.s for the 405ep and turning on the emulator. Just turning on the emulator is insufficient. The Timesys toolchain isn't the only one out there specifically for the 405ep. Greg Weeks ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: floating point operation of ppc 2005-11-11 12:51 ` Greg Weeks @ 2005-11-11 19:35 ` Eugene Surovegin 2005-11-11 19:47 ` Greg Weeks 0 siblings, 1 reply; 4+ messages in thread From: Eugene Surovegin @ 2005-11-11 19:35 UTC (permalink / raw) To: Greg Weeks; +Cc: linuxppc-embedded On Fri, Nov 11, 2005 at 07:51:31AM -0500, Greg Weeks wrote: > lily wrote: > > > hi,all: > > i build an embedded linux on powerpc 405ep,i need execute floating > > point operation,and i enable "math emulate" option in kernel, i run a > > while(1)loop ,in the loop there was floating point expression ,after > > test ,i found the while (1) exit because of the floating point > > computation,that is the floating point can't execute on ppc > > stablely.Is there someone meets the same problems ,please give me some > > suggestion,thanks!!! > > The 405ep has some errata on floating point use. Are you sure it was 405ep? There is no floating point errata for this chip due to the simple reason, it doesn't support floating point in hardware at all. You probably confusing it with 440ep. I'm not aware of any 405ep specific toolchain. In fact, all what is needed is simple 4xx specific toolchain with soft-float enabled by default. This is how floating point is usually done for 4xx - just soft emulation in user-space by the compiler without in-kernel emulation, which is slow. -- Eugene ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: floating point operation of ppc 2005-11-11 19:35 ` Eugene Surovegin @ 2005-11-11 19:47 ` Greg Weeks 0 siblings, 0 replies; 4+ messages in thread From: Greg Weeks @ 2005-11-11 19:47 UTC (permalink / raw) To: Eugene Surovegin; +Cc: linuxppc-embedded Eugene Surovegin wrote: >On Fri, Nov 11, 2005 at 07:51:31AM -0500, Greg Weeks wrote: > > >>lily wrote: >> >> >> >>>hi,all: >>>i build an embedded linux on powerpc 405ep,i need execute floating >>>point operation,and i enable "math emulate" option in kernel, i run a >>>while(1)loop ,in the loop there was floating point expression ,after >>>test ,i found the while (1) exit because of the floating point >>>computation,that is the floating point can't execute on ppc >>>stablely.Is there someone meets the same problems ,please give me some >>>suggestion,thanks!!! >>> >>> >>The 405ep has some errata on floating point use. >> >> > >Are you sure it was 405ep? There is no floating point errata for this >chip due to the simple reason, it doesn't support floating point in >hardware at all. > >You probably confusing it with 440ep. > > > You're right. It was the 440ep. The 405ep BSP is using the 4xx toolchain. I don't think I've ever tried the math emulator on a 405. Greg Weeks ^ permalink raw reply [flat|nested] 4+ messages in thread
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2005-11-11 9:13 ` floating point operation of ppc lily
2005-11-11 12:51 ` Greg Weeks
2005-11-11 19:35 ` Eugene Surovegin
2005-11-11 19:47 ` Greg Weeks
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