On 21 September 2011 03:48, Mircea Gherzan <[email protected]> wrote: > Hi, > > Is there a serious reason to have the armhf gcc output Thumb code by > default? (--with-mode=thumb in gcc -v)
Yes, armhf is not modelled after Debian armel, but after Ubuntu armel (-march=armv7-a -mfpu=vfpv3 -mthumb -mfloat-abi=softfp), the only difference being the abi (hard instead of softfp). Initial benchmarks showed that performance gains of arm mode vs thumb are not that significant except in special cases (eg. ffmpeg where arm mode is used directly anyway), but the size gains are quite measurable (20% size reduction is not unusual), so thumb mode was decided to be used by default. In fact, in some cases thumb mode was actually faster as there more L1/L2 cache space for data so data-bound loops might actually benefit from the code size reduction. > > AFAICT, the armhf and armel binaries are compiled in ARM mode. > Furthermore, the armel gcc also compiles to ARM mode. armhf is compiled in thumb mode entirely, except for specific packages that need arm mode. Regards Konstantinos -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/cabsevwujcbsznex9xf4tyzlybayu9hvojcvc-amohywd3-e...@mail.gmail.com
