From: Aneesh V <aneesh@ti.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [RFC PATCH 0/4] Enable Thumb build for ARM platforms
Date: Mon, 06 Feb 2012 17:56:10 +0530 [thread overview]
Message-ID: <4F2FC6E2.8080209@ti.com> (raw)
In-Reply-To: <1328528248-20872-1-git-send-email-aneesh@ti.com>
On Monday 06 February 2012 05:07 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.
>
> I would request all who are interested in this feature to test it
> and give feedback. To make that easier I have pushed my patches
> here (along with the timer patch from Nicolas that fixes boot on
> OMAP4):
>
> git at github.com:aneeshv/u-boot.git
> branch: thumb
>
> To enable support for new platforms you just need to add
> CONFIG_SYS_THUMB_BUILD in your config file.
Some statistics:
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%
That is, performance actually improved marginally for the Thumb
build, maybe because of the reduced image sizes.
br,
Aneesh
next prev parent reply other threads:[~2012-02-06 12:26 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-06 11:37 [U-Boot] [RFC PATCH 0/4] Enable Thumb build for ARM platforms Aneesh V
2012-02-06 11:37 ` [U-Boot] [RFC PATCH 1/4] ARM: enable Thumb build Aneesh V
2012-02-06 18:45 ` Tom Rini
2012-02-07 7:43 ` Aneesh V
2012-02-06 11:37 ` [U-Boot] [RFC PATCH 2/4] OMAP3+: fix issues with " Aneesh V
2012-02-06 21:06 ` Albert ARIBAUD
2012-02-07 7:49 ` Aneesh V
2012-02-09 8:58 ` Aneesh V
2012-02-06 11:37 ` [U-Boot] [RFC PATCH 3/4] OMAP3+: Use -march=armv7-a and thereby enable Thumb-2 Aneesh V
2012-02-06 11:37 ` [U-Boot] [RFC PATCH 4/4] OMAP4: enable Thumb build Aneesh V
2012-02-06 12:26 ` Aneesh V [this message]
2012-02-06 13:22 ` [U-Boot] [RFC PATCH 0/4] Enable Thumb build for ARM platforms Aneesh V
2012-02-15 13:57 ` [U-Boot] [PATCH " Aneesh V
2012-02-15 13:57 ` [U-Boot] [PATCH 1/4] ARM: enable Thumb build Aneesh V
2012-02-15 13:57 ` [U-Boot] [PATCH 2/4] arm: add %function attribute to assembly functions Aneesh V
2012-02-17 11:09 ` Aneesh V
2012-02-18 10:13 ` Albert ARIBAUD
2012-02-18 13:24 ` Aneesh V
2012-02-18 15:04 ` Albert ARIBAUD
2012-02-18 16:34 ` Aneesh V
2012-02-18 16:48 ` Albert ARIBAUD
2012-02-20 16:08 ` Aneesh V
2012-02-23 11:06 ` Aneesh V
2012-02-17 17:13 ` Mike Frysinger
2012-02-18 11:12 ` Aneesh V
2012-02-18 11:34 ` Albert ARIBAUD
2012-02-18 22:03 ` Simon Glass
2012-02-19 7:15 ` Mike Frysinger
2012-02-20 20:07 ` Tom Rini
2012-02-20 21:53 ` Simon Glass
2012-02-21 4:19 ` Mike Frysinger
2012-02-21 4:44 ` Simon Glass
2012-02-21 14:33 ` Tom Rini
2012-02-21 15:42 ` Mike Frysinger
2012-02-21 18:03 ` Aneesh V
2012-02-21 19:28 ` Mike Frysinger
2012-02-21 20:01 ` Aneesh V
2012-02-21 4:18 ` Mike Frysinger
2012-02-15 13:57 ` [U-Boot] [PATCH 3/4] armv7: Use -march=armv7-a and thereby enable Thumb-2 Aneesh V
2012-02-15 13:57 ` [U-Boot] [PATCH 4/4] OMAP4: enable Thumb build Aneesh V
2012-02-23 13:39 ` [U-Boot] [PATCH v2 1/5] arm: adapt asm/linkage.h from Linux Aneesh V
2012-02-23 14:01 ` Aneesh V
2012-02-23 13:39 ` [U-Boot] [PATCH v2 2/5] armv7: add appropriate headers for assembly functions Aneesh V
2012-02-23 13:39 ` [U-Boot] [PATCH v2 3/5] ARM: enable Thumb build Aneesh V
2012-02-23 14:57 ` Mike Frysinger
2012-02-23 17:28 ` Aneesh V
2012-02-23 17:34 ` Tom Rini
2012-02-23 17:49 ` Aneesh V
2012-02-23 17:51 ` Tom Rini
2012-02-23 18:09 ` Aneesh V
2012-02-23 18:13 ` Aneesh V
2012-02-23 18:05 ` Mike Frysinger
2012-02-23 18:04 ` Mike Frysinger
2012-02-23 18:12 ` Aneesh V
2012-02-23 13:39 ` [U-Boot] [PATCH v2 4/5] armv7: Use -march=armv7-a and thereby enable Thumb-2 Aneesh V
2012-02-23 13:39 ` [U-Boot] [PATCH v2 5/5] OMAP4: enable Thumb build Aneesh V
2012-02-23 14:06 ` [U-Boot] [PATCH v3 1/6] arm: adapt asm/linkage.h from Linux Aneesh V
2012-02-23 14:59 ` Mike Frysinger
2012-02-23 15:24 ` Tom Rini
2012-02-23 16:57 ` Mike Frysinger
2012-02-23 17:40 ` Aneesh V
2012-02-23 23:52 ` Mike Frysinger
2012-02-24 10:30 ` Aneesh V
2012-02-23 14:06 ` [U-Boot] [PATCH v3 2/6] armv7: add appropriate headers for assembly functions Aneesh V
2012-02-23 14:59 ` Mike Frysinger
2012-02-23 14:06 ` [U-Boot] [PATCH v3 3/6] ARM: enable Thumb build Aneesh V
2012-02-23 14:06 ` [U-Boot] [PATCH v3 4/6] armv7: Use -march=armv7-a and thereby enable Thumb-2 Aneesh V
2012-02-23 15:05 ` Mike Frysinger
2012-02-23 17:50 ` Aneesh V
2012-02-23 14:06 ` [U-Boot] [PATCH v3 5/6] omap4+: Avoid using __attribute__ ((__packed__)) Aneesh V
2012-02-23 14:21 ` Tom Rini
2012-02-23 14:56 ` Aneesh V
2012-02-23 15:03 ` Mike Frysinger
2012-02-23 15:03 ` Mike Frysinger
2012-02-23 15:42 ` Aneesh V
2012-02-23 14:06 ` [U-Boot] [PATCH v3 6/6] OMAP4: enable Thumb build Aneesh V
2012-03-08 17:10 ` [U-Boot] [PATCH 1/6] arm: adapt asm/linkage.h from Linux Aneesh V
2012-03-08 17:14 ` Aneesh V
2012-03-08 17:10 ` [U-Boot] [PATCH 2/6] armv7: add appropriate headers for assembly functions Aneesh V
2012-03-08 17:10 ` [U-Boot] [PATCH 3/6] ARM: enable Thumb build Aneesh V
2012-03-08 17:10 ` [U-Boot] [PATCH 4/6] armv7: Use -march=armv7-a and thereby enable Thumb-2 Aneesh V
2012-03-08 17:10 ` [U-Boot] [PATCH 5/6] omap4+: Avoid using __attribute__ ((__packed__)) Aneesh V
2012-03-08 17:10 ` [U-Boot] [PATCH 6/6] OMAP4: enable Thumb build Aneesh V
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