Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] lib: fix 842 build on 32-bit architectures | Date | Wed, 13 May 2015 22:56:39 +0200 |
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Building the 842 code on 32-bit ARM currently results in this link error:
ERROR: "__aeabi_uldivmod" [lib/842/842_decompress.ko] undefined!
The reason is that the __do_index function performs a 64-bit division by a power-of-two number, but it has no insight into the function arguments.
By marking that function inline, the fsize argument is always known at the time that do_index is called, and the compiler is able to replace the extremely expensive 64-bit division with a cheap constant shift operation.
Aside from fixing that link error, this approach should also improve both code size and performance on 32-bit architectures significantly.
Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- Found while building arm32 allmodconfig with gcc-5.0
diff --git a/lib/842/842_decompress.c b/lib/842/842_decompress.c index 6b2b45aecde3..285bf6b6959c 100644 --- a/lib/842/842_decompress.c +++ b/lib/842/842_decompress.c @@ -169,7 +169,7 @@ static int do_data(struct sw842_param *p, u8 n) return 0; } -static int __do_index(struct sw842_param *p, u8 size, u8 bits, u64 fsize) +static inline int __do_index(struct sw842_param *p, u8 size, u8 bits, u64 fsize) { u64 index, offset, total = round_down(p->out - p->ostart, 8); int ret;
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