| # 05:14:40 | sh[4]rm4 | is now known as: sh4rm4 |
| # 08:33:44 | smartin | joins #crosstool-ng |
| # 13:22:22 | imMute | well what the hell, I have a toolchain that apparently built fine, I'm using an identical config (save for CT_LOCAL_TARBALLS_DIR, CT_WORK_DIR, and CT_PREFIX_DIR) and it's failing on the CLooG step |
| # 13:36:50 | imMute | and apparently works fine on the Ubuntu 10.04 build machine, but not the 12.04 machine. must be the newer utilities. |
| # 16:30:32 | smartin | quits |
| # 17:44:30 | smartin | joins #crosstool-ng |
| # 19:55:55 | y_morin | joins #crosstool-ng |
| # 19:59:59 | imMute | y_morin, do you have a minute? |
| # 20:00:25 | y_morin | imMute: Hello! Just ask. |
| # 20:00:33 | imMute | well what the hell, I have a toolchain that apparently built fine, I'm using an identical config (save for CT_LOCAL_TARBALLS_DIR, CT_WORK_DIR, and CT_PREFIX_DIR) and it's failing on the CLooG step |
| # 20:00:37 | imMute | and apparently works fine on the Ubuntu 10.04 build machine, but not the 12.04 machine. must be the newer utilities. |
| # 20:01:28 | y_morin | imMute: probably, there have been quite some changes in 11.04. |
| # 20:01:50 | imMute | okay, well getting that old configuration working on the 12.04 machine isn't really all that important. |
| # 20:01:53 | y_morin | IIRC, we already had an issue on Ubuntu that we could not track. Can't remember what issue it was, though... |
| # 20:02:30 | imMute | however, that toolchain (that's been in use for a year now) was supposedly built with hardware FPU, but I dont think it was |
| # 20:02:43 | y_morin | Maybe time I create a 11.04 chroot to test inthere (I'm using Debian squeeze exclusively on all my machines, and that's what I usually test on) |
| # 20:03:48 | imMute | I whipped up a program that does a floating point divide, and when compiled with no -mfloat-abi= setting, it generates (what I think is) software emulation of the FPU |
| # 20:04:12 | imMute | which is the same assembly that is produced with -mfloat-abi=soft |
| # 20:04:37 | y_morin | imMute: CPU? |
| # 20:05:07 | imMute | Cortex-A8. we're targeting TI's AM3505 which has the Neon FPU |
| # 20:05:39 | imMute | using -mfloat-abi=softfp, it outputs asm that appears to use the FPU |
| # 20:06:05 | imMute | and -mfloat-abi=hard gives that error I'm getting so sick of: "sorry, unimplemented: -mfloat-abi=hard and VFP" |
| # 20:07:11 | imMute | (I can pastebin whatever you need to see, btw, just ask) |
| # 20:08:39 | y_morin | imMute: there already is a sample that enables the Neon extension, but for cortex-a15. You could try from there, and change the settings to cortex-a8 instead. It should work. |
| # 20:08:59 | imMute | I did exactly that, it just got done building a minute ago, I'm testing it now |
| # 20:11:36 | imMute | okay, that one compiles u-boot fine, and seems to compile the kernel fine, but pukes with that VFP error when compiling x-loader. |
| # 20:12:10 | imMute | the gcc call that pukes has the flag -mabi=apcs-gnu which I'm not sure what it does, but when added to my floatingpoint_test.c causes teh same error |
| # 20:13:32 | kos_tom | y_morin: hello. |
| # 20:13:35 | imMute | hmm, I finally found a webpage that describes the different -mabi choices, and it seems apcs-gnu is for the old ABI: http://cross-lfs.org/view/clfs-embedded/arm/cross-tools/abi.html |
| # 20:13:35 | y_morin | imMute: I'm building the toolchain |
| # 20:13:39 | y_morin | kos_tom: hey da! :-) |
| # 20:13:53 | kos_tom | y_morin: I have a kind of newbie question. How does uClibc++ relates (or does not relate) to libstdc++ ? |
| # 20:14:03 | y_morin | kos_tom: it's a replacement. |
| # 20:14:10 | y_morin | intended to be, at least |
| # 20:14:17 | kos_tom | but isn't libstdc++ part of the gcc sources? |
| # 20:14:29 | kos_tom | I thought it was kind of "mandatory" as soon as you wanted to use C++ with gcc |
| # 20:15:11 | y_morin | kos_tom: libstdc++ is part of gcc _sources_ and built with gcc. But if you are sneaky enough, you can switch the installed libstdc++ with uclibc++ |
| # 20:15:33 | imMute | y_morin: thie config I used is here: https://gist.github.com/2838649 |
| # 20:16:05 | y_morin | kos_tom: idea is: 1) build gcc with libstdc++, 2) build uClibc++, 3) trash installed libstdc++, 4) install uClibc++. |
| # 20:16:08 | kos_tom | y_morin: oh, so you build gcc normally with libstdc++, but then you later replace libstdc++ by uclibc++? sounds a bit hackish, no? |
| # 20:16:13 | kos_tom | y_morin: ok |
| # 20:16:36 | kos_tom | y_morin: and what's roughly the compatibility coverage of uClibc++ ? and the size advantage? |
| # 20:16:39 | y_morin | kos_tom: uClibc++ requires some bits from libstdc++ anyway |
| # 20:17:10 | y_morin | kos_tom: http://cxx.uclibc.org/status.html |
| # 20:18:01 | y_morin | kos_tom: page not really up-to-date, but roughly correct. |
| # 20:18:43 | y_morin | kos_tom: with the recent additions by Bernhard (which seems to have taken maintainership_ |
| # 20:19:03 | y_morin | imMute: let me look at that... |
| # 20:20:03 | y_morin | imMute: CT_ARCH_FPU="neon" <- this is not correct, afaik. It's "neon-vfpv4", iirc. |
| # 20:22:03 | y_morin | kos_tom: yes, the size is an important goal. As uClibc vs. glibc, you have uClibc++ vs. libstdc++. And it's configurable, so you can axe out any suport you don't need. |
| # 20:23:32 | imMute | y_morin: yes. I think my problem with x-loader was related to that -mabi=apcs-gnu which makes it use the "old ABI" |
| # 20:23:42 | imMute | (for ARMv4 and older cores) |
| # 20:41:00 | imMute | interesting. I made it build x-loader with -mabi=aapcs instead of apcs-gnu and it pukes towards the end with: |
| # 20:41:26 | imMute | /home/msickler/ctng-C/C4-cortexa15-hard/x-tools-C4a/arm-cortexa8-linux-gnueabi/bin/../lib/gcc/arm-cortexa8-linux-gnueabi/4.6.3/libgcc.a(_dvmd_lnx.o): In function '__aeabi_ldiv0': |
| # 20:41:34 | imMute | /tmp/ctng/C4-build/src/gcc-4.6.3/libgcc/../gcc/config/arm/lib1funcs.asm:1266: undefined reference to 'raise' |
| # 20:44:10 | imMute | that "__aeabi_ldiv0" looks awfully familiar to software floating point |
| # 20:46:20 | imMute | y_morin: what do you make of that? |
| # 20:47:18 | y_morin | imMute: No idea... :-/ |
| # 20:47:25 | y_morin | imMute: gcc-4.5 ? |
| # 20:47:57 | imMute | what about it? (I have no idea which versions of gcc, glibc, etc that I should be using) |
| # 20:49:10 | y_morin | imMute: OK, you're using gcc-4.6.3. |
| # 20:50:22 | y_morin | imMute: is it even possible to use hard-floats in x-loader at all? Because, it being a bootloader, I would not be surprised if it can't handle the FPU status... |
| # 20:51:32 | imMute | That makes sense, come to think of it. shouldn't gcc be able to generate the software FPU though? |
| # 20:54:56 | imMute | huzzah. the trick was -mabi=apcs-gnu AND -mfloat-abi=soft |
| # 20:56:08 | imMute | what would you advise for picking version numbers for GCC, binutils, glibc, etc? |
| # 21:14:57 | y_morin | imMute: I have no real advice. Older version (eg. gcc-4.4.x) is more tested than more ceent version. |
| # 21:15:47 | y_morin | 4.5 should be relatively stable, though I did not really build a toolchain for production recently... |
| # 21:20:43 | smartin | quits |
| # 22:04:20 | y_morin | quits : Quit: Night! |