patch-2.1.101 linux/arch/mips/lib/csum_partial.S

• Lines: 243
• Date: Fri May 8 00:13:24 1998
• Orig file: v2.1.100/linux/arch/mips/lib/csum_partial.S
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.100/linux/arch/mips/lib/csum_partial.S linux/arch/mips/lib/csum_partial.S
@@ -0,0 +1,242 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 1998 Ralf Baechle
+ *
+ * $Id: csum_partial.S,v 1.1 1998/05/04 09:18:08 ralf Exp $
+ */
+#include <sys/asm.h>
+#include <sys/regdef.h>
+
+#define ADDC(sum,reg)			\
+	addu	sum, reg;		\
+	sltu	v1, sum, reg;		\
+	addu	sum, v1
+
+#define CSUM_BIGCHUNK(src, offset, sum, t0, t1, t2, t3) \
+	lw	t0, (offset + 0x00)(src); \
+	lw	t1, (offset + 0x04)(src); \
+	lw	t2, (offset + 0x08)(src); \
+	lw	t3, (offset + 0x0c)(src); \
+	ADDC(sum, t0);                    \
+	ADDC(sum, t1);                    \
+	ADDC(sum, t2);                    \
+	ADDC(sum, t3);                    \
+	lw	t0, (offset + 0x10)(src); \
+	lw	t1, (offset + 0x14)(src); \
+	lw	t2, (offset + 0x18)(src); \
+	lw	t3, (offset + 0x1c)(src); \
+	ADDC(sum, t0);                    \
+	ADDC(sum, t1);                    \
+	ADDC(sum, t2);                    \
+	ADDC(sum, t3);                    \
+
+/*
+ * a0: source address
+ * a1: length of the area to checksum
+ * a2: partial checksum
+ */
+
+#define src a0
+#define dest a1
+#define sum v0
+
+	.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)
+	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)
+	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
+	move t7, zero
+
+	sltiu	t8, a1, 0x8
+	bnez	t8, small_csumcpy		/* < 8 bytes to copy */
+	 move	t2, a1
+
+	beqz	a1, out
+	 andi	t7, src, 0x1			/* odd buffer? */
+
+hword_align:
+	beqz	t7, word_align
+	 andi	t8, src, 0x2
+
+	lbu	t0, (src)
+	subu	a1, a1, 0x1
+#ifdef __MIPSEL__
+	sll	t0, t0, 8
+#endif
+	ADDC(sum, t0)
+	addu	src, src, 0x1
+	andi	t8, src, 0x2
+
+word_align:
+	beqz	t8, dword_align
+	 sltiu	t8, a1, 56
+
+	lhu	t0, (src)
+	subu	a1, a1, 0x2
+	ADDC(sum, t0)
+	sltiu	t8, a1, 56
+	addu	src, src, 0x2
+
+dword_align:
+	bnez	t8, do_end_words
+	 move	t8, a1
+
+	andi	t8, src, 0x4
+	beqz	t8, qword_align
+	 andi	t8, src, 0x8
+
+	lw	t0, 0x00(src)
+	subu	a1, a1, 0x4
+	ADDC(sum, t0)
+	addu	src, src, 0x4
+	andi	t8, src, 0x8
+
+qword_align:
+	beqz	t8, oword_align
+	 andi	t8, src, 0x10
+
+	lw	t0, 0x00(src)
+	lw	t1, 0x04(src)
+	subu	a1, a1, 0x8
+	ADDC(sum, t0)
+	ADDC(sum, t1)
+	addu	src, src, 0x8
+	andi	t8, src, 0x10
+
+oword_align:
+	beqz	t8, begin_movement
+	 srl	t8, a1, 0x7
+
+	lw	t3, 0x08(src)
+	lw	t4, 0x0c(src)
+	lw	t0, 0x00(src)
+	lw	t1, 0x04(src)
+	ADDC(sum, t3)
+	ADDC(sum, t4)
+	ADDC(sum, t0)
+	ADDC(sum, t1)
+	subu	a1, a1, 0x10
+	addu	src, src, 0x10
+	srl	t8, a1, 0x7
+
+begin_movement:
+	beqz	t8, 1f
+	 andi	t2, a1, 0x40
+
+move_128bytes:
+	CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
+	CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
+	CSUM_BIGCHUNK(src, 0x40, sum, t0, t1, t3, t4)
+	CSUM_BIGCHUNK(src, 0x60, sum, t0, t1, t3, t4)
+	subu	t8, t8, 0x01
+	bnez	t8, move_128bytes
+	 addu	src, src, 0x80
+
+1:
+	beqz	t2, 1f
+	 andi	t2, a1, 0x20
+
+move_64bytes:
+	CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
+	CSUM_BIGCHUNK(src, 0x20, sum, t0, t1, t3, t4)
+	addu	src, src, 0x40
+
+1:
+	beqz	t2, do_end_words
+	 andi	t8, a1, 0x1c
+
+move_32bytes:
+	CSUM_BIGCHUNK(src, 0x00, sum, t0, t1, t3, t4)
+	andi	t8, a1, 0x1c
+	addu	src, src, 0x20
+
+do_end_words:
+	beqz	t8, maybe_end_cruft
+	 srl	t8, t8, 0x2
+
+end_words:
+	lw	t0, (src)
+	subu	t8, t8, 0x1
+	ADDC(sum, t0)
+	bnez	t8, end_words
+	 addu	src, src, 0x4
+
+maybe_end_cruft:
+	andi	t2, a1, 0x3
+
+small_memcpy:
+ j small_csumcpy; move a1, t2
+	beqz	t2, out
+	 move	a1, t2
+
+end_bytes:
+	lb	t0, (src)
+	subu	a1, a1, 0x1
+	bnez	a2, end_bytes
+	 addu	src, src, 0x1
+
+out:
+	jr	ra
+	 move	v0, sum
+	END(csum_partial)