Hi Shinya,
2011/3/17 Shinya Kuribayashi skuribay@pobox.com:
On 03/16/2011 11:41 PM, Daniel Schwierzeck wrote:
Is my approach with -march acceptable? This is more important to me for supporting new SoCs with 24k and 34k CPU cores. I think its a clean approach to use a default Mips32 architecture optimization plus a per CPU optimization configured in the SoC directories.
IIUC this is a binutils related issue.
@@ -20,20 +20,13 @@ # Foundation, Inc., 59 Temple Place, Suite 330, Boston, # MA 02111-1307 USA # -v=$(shell $(AS) --version | grep 'GNU assembler' | egrep -o '2.[0-9.]+' | cut -d. -f2) -MIPSFLAGS:=$(shell \ -if [ "$v" -lt "14" ]; then \
- echo "-mcpu=4kc"; \
-else \
- echo "-march=4kc -mtune=4kc"; \
-fi)
[...] +# Optimization flags for all Mips32 CPUs +MIPSFLAGS = $(call cc-option,-march=mips32r2,-mips32r2 -Wa,-mips32r2)
According to GNU gas NEWS, mips32r2 support was introduced in 2.14:
http://sourceware.org/cgi-bin/cvsweb.cgi/~checkout~/src/gas/NEWS?rev=1.117&a...
On the other hand, we have a number of the ELDK releases so far, and their binutils versions vary from 2.11 (ELDK2.1.0) to 2.16.1 (ELDK4.1).
2.1.0: http://mirror.switch.ch/ftp/mirror/eldk/2.1.0/eldk-mips-linux-x86/README.htm... 3.0: (N/A for MIPS?) 3.1: http://mirror.switch.ch/ftp/mirror/eldk/3.1/mips-linux-x86/distribution/READ... 3.1.1: http://mirror.switch.ch/ftp/mirror/eldk/3.1.1/mips-linux-x86/distribution/RE... 4.0: http://mirror.switch.ch/ftp/mirror/eldk/4.0/mips-linux-x86/distribution/READ... http://www.denx.de/en/News/PressReleaseELDK40 4.1: http://mirror.switch.ch/ftp/mirror/eldk/4.1/mips-linux-x86/distribution/READ... http://www.denx.de/en/News/PressReleaseELDK41 4.2: (N/A for MIPS?)
Does above change break any builds with older binutils? Personally, I'm ok with dropping older toolchains to some extent. However, if it breaks builds with older toolchains, strictly speaking older versions of the ELDK releases, the decision is up to Wolfgang.
I did some researching and testing with ELDK-4.1, ELDK-4.0 and ELDK-3.1.1.
In ELDK-3.1.1 we have: - mips_4KC-gcc (GCC) 3.3.3 (DENX ELDK 3.1.1 3.3.3-9) - GNU assembler 2.14 20030612
Therefore mips32r2 is already supported. But there is another problem with this binutils version. The latest additions to mips.lds and u-boot.lds for supporting recent binutils are causing parse errors. Thus ELDK-3.1.1 and earlier are not functional with mainline U-Boot anyway. ELDK-4.0 and 4.1 with gcc-4.0.0 and binutils-2.16.1 are working properly.
I suggest to drop official support for ELDK-3.1.1 / binutils-2.14 and earlier.
Best regards Daniel