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FS#11335 - Make ARM assembly functions thumb-friendly
Attached to Project:
Rockbox
Opened by Rafaël Carré (funman) - Sunday, 30 May 2010, 23:37 GMT+2
Last edited by Rafaël Carré (funman) - Friday, 11 June 2010, 06:42 GMT+2
Opened by Rafaël Carré (funman) - Sunday, 30 May 2010, 23:37 GMT+2
Last edited by Rafaël Carré (funman) - Friday, 11 June 2010, 06:42 GMT+2
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DetailsA lot of functions use return instructions which won't set the T bit if the caller was running in thumb:
- ldm reg, { ..., pc } works on armv5 but not armv4t - ldr pc, function works on ARMv5 and + - add/sub/bic/orr/mov pc, lr works on armv7 but not before reference is http://webcache.googleusercontent.com/search?q=cache:saLD8BqZXhQJ:www.riscosopen.org/wiki/documentation/pages/ARMv7%2Bcompatibility%2Bprimer+thumb+interwork+ldm+ldr+armv7&cd=1&hl=fr&ct=clnk DDI0100E (ARMv5 architecture reference manual) says of mov: If <Rd> is R15, the SPSR of the current mode is copied to the CPSR This patch changes all occurences of these instructions which could be run on armv4t (e.g. PP, AMSv1, ..). I don't think I have missed any, I used grep -E "(((ldr|mov) *)|(ldm.*))pc" to find all the occurences. I could have changed some code which would not run on ARMv4 though. Cost of this change on ldm (the most used) - 4 more bytes per return - 1 more cycle on ARM7TDMI, no effect on newer CPUs See 
thumb.diff
(44.7 KiB)
b/apps/codecs/demac/libdemac/predictor-arm.S | 6 + b/apps/codecs/lib/mdct_arm.S | 11 ++- b/apps/codecs/libatrac/atrac3_arm.S | 6 + b/apps/codecs/libffmpegFLAC/arm.S | 3 b/apps/codecs/libmad/dct32_arm.S | 3 b/apps/codecs/libmad/imdct_l_arm.S | 6 + b/apps/codecs/libmad/synth_full_arm.S | 12 ++- b/apps/codecs/libmusepack/synth_filter_arm.S | 6 + b/apps/codecs/libspeex/filters_arm4.S | 15 +++- b/apps/codecs/libtta/filter_arm.S | 6 + b/apps/codecs/libwavpack/arm.S | 3 b/apps/codecs/libwavpack/arml.S | 3 b/apps/dsp_arm.S | 42 ++++++++----- b/apps/eq_arm.S | 3 b/apps/plugins/SOURCES | 1 b/apps/plugins/mpegplayer/idct_arm.S | 9 +- b/apps/plugins/mpegplayer/motion_comp_arm_s.S | 48 ++++++++++----- b/apps/plugins/pacbox/pacbox_arm.S | 3 b/apps/plugins/test_codec.c | 2 b/apps/recorder/jpeg_idct_arm.S | 24 +++++-- b/firmware/rolo.c | 12 ++- b/firmware/target/arm/as3525/debug-as3525.c | 9 ++ b/firmware/target/arm/as3525/lcd-as-e200v2-fuze-fuzev2.S | 6 + b/firmware/target/arm/as3525/sansa-clip/lcd-as-clip.S | 3 b/firmware/target/arm/ata-as-arm.S | 12 ++- b/firmware/target/arm/ipod/lcd-as-gray.S | 12 ++- b/firmware/target/arm/ipod/video/lcd-as-video.S | 6 + b/firmware/target/arm/iriver/h10/lcd-as-h10.S | 6 + b/firmware/target/arm/lcd-as-memframe.S | 9 +- b/firmware/target/arm/memcpy-arm.S | 3 b/firmware/target/arm/memmove-arm.S | 3 b/firmware/target/arm/memset-arm.S | 3 b/firmware/target/arm/memset16-arm.S | 3 b/firmware/target/arm/olympus/mrobe-100/lcd-as-mr100.S | 3 b/firmware/target/arm/pbell/vibe500/lcd-as-vibe500.S | 6 + b/firmware/target/arm/philips/hdd1630/lcd-as-hdd1630.S | 6 + b/firmware/target/arm/samsung/yh820/lcd-as-yh820.S | 6 + b/firmware/target/arm/samsung/yh920/lcd-as-yh920.S | 3 b/firmware/target/arm/samsung/yh925/lcd-as-yh925.S | 6 + b/firmware/target/arm/sandisk/sansa-c200/lcd-as-c200.S | 6 + b/firmware/thread.c | 8 +- 41 files changed, 229 insertions(+), 114 deletions(-) |
This task depends upon
Closed by Rafaël Carré (funman)
Friday, 11 June 2010, 06:42 GMT+2
Reason for closing: Accepted
Additional comments about closing: r26756
Friday, 11 June 2010, 06:42 GMT+2
Reason for closing: Accepted
Additional comments about closing: r26756
I think we can return from vectors with anything, the spsr will be restored with the T bit (must check)
e200v1 built with -mthumb still doesn't boot though
Modify some comments
Remove unrelated diffs
% grep -rE "(((mov|ldr) *)|(ldm.*))pc" *|cut -d: -f1|sort|uniq
apps/codecs/demac/libdemac/udiv32_arm.S # ARMv5+
apps/codecs/libtremor/mapping0.c # false positive (ldmia %[pcm])
apps/dsp_arm_v6.S # ARMv6+
apps/plugins/mpegplayer/idct_armv6.S # ARMv6+
apps/plugins/mpegplayer/motion_comp_arm_s.S # branches to local ARM functions
apps/recorder/jpeg_idct_arm.S # ARMv5+
firmware/target/arm/as3525/sansa-clipplus/lcd-as-clip-plus.S # ARMv5
firmware/target/arm/as3525/sansa-clipv2/lcd-as-clipv2.S # ARMv5
# crt0 ignored: entered in ARM state, returning from exceptions restore SPSR into CPSR
firmware/target/arm/at91sam/lyre_proto1/crt0.S
firmware/target/arm/crt0-pp-bl.S
firmware/target/arm/crt0-pp.S
firmware/target/arm/crt0.S
firmware/target/arm/imx31/crt0.S
firmware/target/arm/pnx0101/crt0-pnx0101.S
firmware/target/arm/s3c2440/crt0.S
firmware/target/arm/s5l8700/crt0.S
firmware/target/arm/tcc77x/crt0.S
firmware/target/arm/tcc780x/crt0.S
firmware/target/arm/support-arm.S # ARMv5+
firmware/target/arm/s3c2440/system-s3c2440.c # return from exception (irq), restore SPSR into CPSR
# tools and bootloaders ignored
rbutil/mkamsboot/dualboot/dualboot.S
rbutil/mkamsboot/dualboot/nrv2e_d8.S
rbutil/mktccboot/mktccboot.c
bootloader/creativezvm.c
bootloader/ipodnano2g.c
Still not booting on e200v1 (built with -mthumb) - not sure why
i'll make some test_codec run to confirm it hasn't any noticeable impact
| *Nero AAC-HE* |||||
| 64kaache.m4a | 164.17% realtime | Decode time - 107.21s | 151.06MHz | 100.85%|
| *Cook (RA)* |||||
| cook_mono_64.ra | 1306.83% realtime | Decode time - 13.46s | 18.97MHz | 100.00%|
| cook_stereo_32.ra | 1417.40% realtime | Decode time - 12.41s | 17.49MHz | 100.00%|
| cook_stereo_64.ra | 694.15% realtime | Decode time - 25.34s | 35.72MHz | 99.97%|
| cook_stereo_96.ra | 678.36% realtime | Decode time - 25.93s | 36.55MHz | 100.00%|
| *MP3* |||||
| lame_096.mp3 | 833.53% realtime | Decode time - 21.11s | 29.75MHz | 100.23%|
| lame_128.mp3 | 637.30% realtime | Decode time - 27.61s | 38.91MHz | 100.26%|
| *Musepack* |||||
| mpc_096.mpc | 903.90% realtime | Decode time - 19.46s | 27.43MHz | 100.00%|
| mpc_128.mpc | 860.98% realtime | Decode time - 20.43s | 28.80MHz | 99.97%|
| *AAC-LC* |||||
| nero_096.m4a | 571.11% realtime | Decode time - 30.81s | 43.42MHz | - |
| nero_128.m4a | 550.21% realtime | Decode time - 31.98s | 45.07MHz | - |
| *Vorbis* |||||
| vorbis_096.ogg | 658.55% realtime | Decode time - 26.71s | 37.65MHz | - |
| *WMA Standard* |||||
| wma_128.wma | 652.33% realtime | Decode time - 27.21s | 38.01MHz | - |
| wma_96.wma | 659.60% realtime | Decode time - 26.91s | 37.59MHz | - |