> Tom, Albert, > > Does this series look good? Hi Aneesh,
The assembly files (like arch/arm/cpu/armv7/start.S) are still compiled ARM 32 with this patch series, but they call into C files that are compiled -mthumb. Shouldn't the branches be changed into thumb state changing branches (bx/blx) ? In particular I'm looking at the call into board_init_f() -Allen > > On Thursday 08 March 2012 10:50 PM, Aneesh V wrote: > > Thumb is an alternate instruction set available in many > > ARM processors. Below is a detailed description from ARM > > specs: > > > > "The Thumb instruction set is a re-encoded subset of the > > ARM instruction set. Thumb instructions execute in their > > own processor state, with the architecture defining the > > mechanisms required to transition between ARM and Thumb > > states. The key difference is that Thumb instructions are > > half the size of ARM instructions(16 bits compared with 32 > > bits). Greater code density can usually be achieved by using > > the Thumb instruction set in preference to the ARM instruction > > set, at a cost of some reduction in performance" > > > > "In ARMv6T2, Thumb-2 technology is introduced. This technology > > makes it possible to extend the original Thumb instruction set > > with many 32-bit instructions. The range of 32-bit Thumb instructions > > included in ARMv6T2 permits Thumb code to achieve performance > > similar to ARM code, with code density better than that of earlier > > Thumb code. From ARMv6T2, the ARM and Thumb instruction sets provide > > almost identical functionality" > > > > This series adds Thumb support in U-Boot and enables it for > > OMAP4. It also fixes issues faced while booting OMAP4 with > > Thumb-2 images of U-Boot and SPL. > > > > Thumb mode is becoming increasingly relevant for U-Boot with > > the advent of SPL. It's very important to keep SPL size smaller > > considering the internal RAM size constraints on many platforms. > > On OMAP4 the size reduction enables us to use SPL on secure devices > > that have smaller internal RAM available for non-secure world. > > > > To enable support for new platforms you just need to add > > CONFIG_SYS_THUMB_BUILD in your config file. > > > > Tool-chains tried: > > 1. Sourcery G++ Lite 2010q1-202 > > arm-none-linux-gnueabi-gcc (Sourcery G++ Lite 2010q1-202) 4.4.1 > > GNU ld (Sourcery G++ Lite 2010q1-202) - binutils 2.19.51.20090709 > > > > 2. Linaro 4.6-2012.01 > > arm-linux-gnueabi-gcc (crosstool-NG linaro-1.13.1-2012.01-20120125 - > > Linaro GCC 2012.01) 4.6.3 20120105 (prerelease) > > GNU ld (crosstool-NG linaro-1.13.1-2012.01-20120125 - Linaro GCC > 2012.01) 2.22 > > > > Code-size reduction: > > Image ARM build Thumb build % Reduction > > u-boot.bin 190408 144676 24.01% > > u-boot-spl.bin 33200 25096 24.40% > > > > Performance(timestamp just before the main loop): > > ARM build Thumb build % Reduction > > 898510us 878247us -2.25% > > > > Performance actually improved marginally for the Thumb > > build, maybe because of the reduced image sizes. > > > > Aneesh V (6): > > arm: adapt asm/linkage.h from Linux > > armv7: add appropriate headers for assembly functions > > ARM: enable Thumb build > > armv7: Use -march=armv7-a and thereby enable Thumb-2 > > omap4+: Avoid using __attribute__ ((__packed__)) > > OMAP4: enable Thumb build > > > > README | 8 +++++ > > arch/arm/config.mk | 22 +++++++++---- > > arch/arm/cpu/armv7/config.mk | 7 +++- > > arch/arm/cpu/armv7/mx5/lowlevel_init.S | 5 ++- > > arch/arm/cpu/armv7/mx6/lowlevel_init.S | 5 ++- > > arch/arm/cpu/armv7/omap-common/lowlevel_init.S | 14 ++++---- > > arch/arm/cpu/armv7/omap-common/reset.S | 5 ++- > > arch/arm/cpu/armv7/omap3/lowlevel_init.S | 41 ++++++++++++-- > --------- > > arch/arm/cpu/armv7/s5pc1xx/cache.S | 10 +++-- > > arch/arm/cpu/armv7/s5pc1xx/reset.S | 5 ++- > > arch/arm/cpu/armv7/start.S | 13 ++++--- > > arch/arm/cpu/armv7/tegra2/lowlevel_init.S | 5 ++- > > arch/arm/cpu/armv7/u8500/lowlevel.S | 9 +++-- > > arch/arm/include/asm/arch-omap4/mux_omap4.h | 2 +- > > arch/arm/include/asm/arch-omap5/mux_omap5.h | 2 +- > > arch/arm/include/asm/linkage.h | 7 ++++ > > include/configs/omap4_common.h | 2 + > > include/linux/linkage.h | 7 +++- > > 18 files changed, 106 insertions(+), 63 deletions(-) > > create mode 100644 arch/arm/include/asm/linkage.h > > > > _______________________________________________ > U-Boot mailing list > [email protected] > http://lists.denx.de/mailman/listinfo/u-boot nvpublic _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
