Commit d191323b authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: don't use a12 in strncpy_user 



a12 is callee-saved register in xtensa call0 ABI, so a function must not
change it. a10 is not used in this function at all, use it instead of
a12 to avoid saving/restoring it.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent eda8dd12

arch/xtensa/lib/strncpy_user.S

+8 −9
Original line number Diff line number Diff line
@@ -45,7 +45,6 @@ 
#   a9/ tmp

#   a10/ tmp

#   a11/ dst

#   a12/ tmp



.text

ENTRY(__strncpy_user)
@@ -61,7 +60,7 @@ ENTRY(__strncpy_user) 
	bbsi.l	a3, 0, .Lsrc1mod2 # if only  8-bit aligned

	bbsi.l	a3, 1, .Lsrc2mod4 # if only 16-bit aligned

.Lsrcaligned:	# return here when src is word-aligned

	srli	a12, a4, 2	# number of loop iterations with 4B per loop

	srli	a10, a4, 2	# number of loop iterations with 4B per loop

	movi	a9, 3

	bnone	a11, a9, .Laligned

	j	.Ldstunaligned
@@ -102,11 +101,11 @@ EX(10f) s8i a9, a11, 0 # store byte 0 
	.byte	0		# (0 mod 4 alignment for LBEG)

.Laligned:

#if XCHAL_HAVE_LOOPS

	loopnez	a12, .Loop1done

	loopnez	a10, .Loop1done

#else

	beqz	a12, .Loop1done

	slli	a12, a12, 2

	add	a12, a12, a11	# a12 = end of last 4B chunck

	beqz	a10, .Loop1done

	slli	a10, a10, 2

	add	a10, a10, a11	# a10 = end of last 4B chunck

#endif

.Loop1:

EX(11f)	l32i	a9, a3, 0		# get word from src
@@ -118,7 +117,7 @@ EX(10f) s32i a9, a11, 0 # store word to dst 
	bnone	a9, a8, .Lz3		# if byte 3 is zero

	addi	a11, a11, 4		# advance dst pointer

#if !XCHAL_HAVE_LOOPS

	blt	a11, a12, .Loop1

	blt	a11, a10, .Loop1

#endif



.Loop1done:
@@ -185,7 +184,7 @@ EX(10f) s8i a9, a11, 2 
	loopnez	a4, .Lunalignedend

#else

	beqz	a4, .Lunalignedend

	add	a12, a11, a4		# a12 = ending address

	add	a10, a11, a4		# a10 = ending address

#endif /* XCHAL_HAVE_LOOPS */

.Lnextbyte:

EX(11f)	l8ui	a9, a3, 0
@@ -194,7 +193,7 @@ EX(10f) s8i a9, a11, 0 
	beqz	a9, .Lunalignedend

	addi	a11, a11, 1

#if !XCHAL_HAVE_LOOPS

	blt	a11, a12, .Lnextbyte

	blt	a11, a10, .Lnextbyte

#endif



.Lunalignedend: