BACKPORT: ARM: 9039/1: assembler: generalize byte swapping macro into rev_l
Take the 4 instruction byte swapping sequence from the decompressor's head.S, and turn it into a rev_l GAS macro for general use. While at it, make it use the 'rev' instruction when compiling for v6 or later. Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Nicolas Pitre <nico@fluxnic.net> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> (cherry picked from commit 6468e898c67b905ec0f95d9678929135bcaf7f67) (resolved conflict due to different patch context, caused by missing other macros in assembler.h) Bug: 178411248 Change-Id: I8433e97d2880f75cace215f1a8daadec7f29929c Signed-off-by: Eric Biggers <ebiggers@google.com>
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@ -117,10 +117,7 @@
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.macro be32tocpu, val, tmp
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#ifndef __ARMEB__
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/* convert to little endian */
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eor \tmp, \val, \val, ror #16
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bic \tmp, \tmp, #0x00ff0000
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mov \val, \val, ror #8
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eor \val, \val, \tmp, lsr #8
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rev_l \val, \tmp
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#endif
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.endm
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@ -506,4 +506,21 @@ THUMB( orr \reg , \reg , #PSR_T_BIT )
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#define _ASM_NOKPROBE(entry)
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#endif
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/*
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* rev_l - byte-swap a 32-bit value
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*
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* @val: source/destination register
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* @tmp: scratch register
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*/
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.macro rev_l, val:req, tmp:req
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.if __LINUX_ARM_ARCH__ < 6
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eor \tmp, \val, \val, ror #16
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bic \tmp, \tmp, #0x00ff0000
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mov \val, \val, ror #8
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eor \val, \val, \tmp, lsr #8
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.else
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rev \val, \val
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.endif
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.endm
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#endif /* __ASM_ASSEMBLER_H__ */
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