Hi, Michael Cree wrote: > On 15/07/2012, at 8:50 AM, Jonathan Nieder wrote: >> gcc takes full advantage by converting the get_be32 >> calls back to a load and bswap and producing a whole bunch of >> unaligned access traps. > > Alpha does not have a bswap (or similar) instruction. [...] > . If the pointer is unaligned > then two neighbouring aligned 32bit loads are required to ensure > that all four bytes are loaded. If the pointer is aligned then a > single 32bit load gets all the four bytes. Having never looked at > the generated assembler code, I nevertheless suspect that is the > guts of the optimisation --- the compiler can eliminate an access to > memory if it knows the pointer is aligned. How about: gcc takes full advantage by using a single 32-bit load, resulting in a whole bunch of unaligned access traps. You can see the generated assembler with "make block-sha1/sha1.s" and reading the resulting sha1.s file in the current working directory (oops). I don't have an alpha cross-compiler installed or access to an alpha to check for myself. -- >8 -- Subject: Makefile: fix location of listing produced by "make subdir/foo.s" When I invoke "make block-sha1/sha1.s", 'make' runs $(CC) -S without specifying where it should put its output and the output ends up in ./sha1.s. Confusing. Add an -o option to the .s rule to fix this. We were already doing that for most compiler invocations but had forgotten it for the assembler listings. Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx> --- Thanks, Jonathan Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index dc709029..e8d2798f 100644 --- a/Makefile +++ b/Makefile @@ -2230,7 +2230,7 @@ $(ASM_OBJ): %.o: %.S GIT-CFLAGS $(missing_dep_dirs) endif %.s: %.c GIT-CFLAGS FORCE - $(QUIET_CC)$(CC) -S $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $< + $(QUIET_CC)$(CC) -o $@ -S $(ALL_CFLAGS) $(EXTRA_CPPFLAGS) $< ifdef USE_COMPUTED_HEADER_DEPENDENCIES # Take advantage of gcc's on-the-fly dependency generation -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html