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Commit 773ff788 authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Ralf Baechle
Browse files

[MIPS] Optimize flow of csum_partial 



Delete dead codes at end of the function and move small_csumcopy
there.  This makes some labels (maybe_end_cruft, small_memcpy,
end_bytes, out) needless and eliminates some branches.

Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 52ffe760

arch/mips/lib/csum_partial.S

+54 −75
Original line number Diff line number Diff line
@@ -65,64 +65,6 @@ 


	.text

	.set	noreorder



/* unknown src alignment and < 8 bytes to go  */

small_csumcpy:

	move	a1, t2



	andi	t0, a1, 4

	beqz	t0, 1f

	 andi	t0, a1, 2



	/* Still a full word to go  */

	ulw	t1, (src)

	PTR_ADDIU	src, 4

	ADDC(sum, t1)



1:	move	t1, zero

	beqz	t0, 1f

	 andi	t0, a1, 1



	/* Still a halfword to go  */

	ulhu	t1, (src)

	PTR_ADDIU	src, 2



1:	beqz	t0, 1f

	 sll	t1, t1, 16



	lbu	t2, (src)

	 nop



#ifdef __MIPSEB__

	sll	t2, t2, 8

#endif

	or	t1, t2



1:	ADDC(sum, t1)



	/* fold checksum */

	sll	v1, sum, 16

	addu	sum, v1

	sltu	v1, sum, v1

	srl	sum, sum, 16

	addu	sum, v1



	/* odd buffer alignment? */

	beqz	t7, 1f

	 nop

	sll	v1, sum, 8

	srl	sum, sum, 8

	or	sum, v1

	andi	sum, 0xffff

1:

	.set	reorder

	/* Add the passed partial csum.  */

	ADDC(sum, a2)

	jr	ra

	.set	noreorder



/* ------------------------------------------------------------------------- */



	.align	5

LEAF(csum_partial)

	move	sum, zero
@@ -132,7 +74,6 @@ LEAF(csum_partial) 
	bnez	t8, small_csumcpy		/* < 8 bytes to copy */

	 move	t2, a1



	beqz	a1, out

	andi	t7, src, 0x1			/* odd buffer? */



hword_align:
@@ -232,7 +173,8 @@ move_32bytes: 
	PTR_ADDU	src, src, 0x20



do_end_words:

	beqz	t8, maybe_end_cruft

	beqz	t8, small_csumcpy

	 andi	t2, a1, 0x3

	LONG_SRL	t8, t8, 0x2



end_words:
@@ -242,21 +184,58 @@ end_words: 
	bnez	t8, end_words

	 PTR_ADDU	src, src, 0x4



maybe_end_cruft:

	andi	t2, a1, 0x3



small_memcpy:

 j small_csumcpy; move a1, t2		/* XXX ??? */

	beqz	t2, out

/* unknown src alignment and < 8 bytes to go  */

small_csumcpy:

	move	a1, t2



end_bytes:

	lb	t0, (src)

	LONG_SUBU	a1, a1, 0x1

	bnez	a2, end_bytes

	 PTR_ADDU	src, src, 0x1

	andi	t0, a1, 4

	beqz	t0, 1f

	 andi	t0, a1, 2



	/* Still a full word to go  */

	ulw	t1, (src)

	PTR_ADDIU	src, 4

	ADDC(sum, t1)



1:	move	t1, zero

	beqz	t0, 1f

	 andi	t0, a1, 1



	/* Still a halfword to go  */

	ulhu	t1, (src)

	PTR_ADDIU	src, 2



1:	beqz	t0, 1f

	 sll	t1, t1, 16



	lbu	t2, (src)

	 nop



#ifdef __MIPSEB__

	sll	t2, t2, 8

#endif

	or	t1, t2



1:	ADDC(sum, t1)



	/* fold checksum */

	sll	v1, sum, 16

	addu	sum, v1

	sltu	v1, sum, v1

	srl	sum, sum, 16

	addu	sum, v1



out:

	/* odd buffer alignment? */

	beqz	t7, 1f

	 nop

	sll	v1, sum, 8

	srl	sum, sum, 8

	or	sum, v1

	andi	sum, 0xffff

1:

	.set	reorder

	/* Add the passed partial csum.  */

	ADDC(sum, a2)

	jr	ra

	 move	v0, sum

	.set	noreorder

	END(csum_partial)