patch-1.3.48 linux/include/asm-mips/checksum.h

• Lines: 180
• Date: Wed Dec 13 12:39:45 1995
• Orig file: v1.3.47/linux/include/asm-mips/checksum.h
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.47/linux/include/asm-mips/checksum.h linux/include/asm-mips/checksum.h
@@ -0,0 +1,179 @@
+/*
+ * include/asm-mips/checksum.h
+ *
+ * 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) 1995 by Ralf Baechle
+ */
+#ifndef __ASM_MIPS_CHECKSUM_H
+#define __ASM_MIPS_CHECKSUM_H
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic
+ *
+ * this function must be called with even lengths, except
+ * for the last fragment, which may be odd
+ *
+ * it's best to have buff aligned on a 32-bit boundary
+ */
+unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum);
+
+/*
+ * the same as csum_partial, but copies from src while it
+ * checksums
+ *
+ * here even more important to align src and dst on a 32-bit (or even
+ * better 64-bit) boundary
+ */
+unsigned int csum_partial_copy(const char *src, char *dst, int len, int sum);
+
+/*
+ * the same as csum_partial, but copies from user space (but on the alpha
+ * we have just one address space, so this is identical to the above)
+ */
+#define csum_partial_copy_fromuser csum_partial_copy
+  
+/*
+ *	This is a version of ip_compute_csum() optimized for IP headers,
+ *	which always checksum on 4 octet boundaries.
+ *
+ *	By Jorge Cwik <jorge@laser.satlink.net>, adapted for linux by
+ *	Arnt Gulbrandsen.
+ */
+static inline unsigned short ip_fast_csum(unsigned char * iph,
+					  unsigned int ihl)
+{
+	unsigned short int sum;
+	unsigned long	dummy1, dummy2;
+
+	/*
+	 * This is optimized for 32-bit MIPS processors.
+	 * I tried it in plain C but the generated code looks to bad to
+	 * use with old first generation MIPS CPUs.
+	 * Using 64-bit code could even further improve these routines.
+	 */
+	__asm__("
+	.set	noreorder
+	.set	noat
+	lw	%0,(%3)
+	subu	%1,4
+	blez	%1,2f
+	sll	%1,%4,2			# delay slot
+	lw	%2,4(%3)
+	addu	%1,%3			# delay slot
+	addu	%0,%2
+	sltu	$1,%0,%2
+	lw	%2,8(%3)
+	addu	%0,$1
+	addu	%0,%2
+	sltu	$1,%0,%2
+	lw	%2,12(%3)
+	addu	%0,$1
+	addu	%0,%2
+	sltu	$1,%0,%2
+	addu	%0,$1
+1:	lw	%2,16(%3)
+	addu	%1,4
+	addu	%0,%2
+	sltu	$1,%0,%2
+	bne	%1,%3,1b
+	addu	%0,$1			# delay slot
+	srl	$1,%0,16
+	addu	%0,$1
+	sltu	$1,%0,$1
+	addu	%0,$1
+	nor	%0,$0,%0
+	andi	%0,0xffff
+2:	.set	at
+	.set	reorder"
+	: "=r" (sum), "=r" (dummy1), "=r" (dummy2)
+	: "r" (iph), "r"(ihl)
+	: "$1");
+
+	return sum;
+}
+
+/*
+ * computes the checksum of the TCP/UDP pseudo-header
+ * returns a 16-bit checksum, already complemented
+ */
+static inline unsigned short int csum_tcpudp_magic(unsigned long saddr,
+						   unsigned long daddr,
+						   unsigned short len,
+						   unsigned short proto,
+						   unsigned int sum)
+{
+    __asm__("
+	.set	noat
+	addu	%0,%2
+	sltu	$1,%0,%2
+	addu	%0,$1
+	addu	%0,%3
+	sltu	$1,%0,%3
+	addu	%0,$1
+	addu	%0,%4
+	sltu	$1,%0,%4
+	addu	%0,$1
+	srl	$1,%0,16
+	addu	%0,$1
+	sltu	$1,%0,$1
+	addu	%0,$1
+	nor	%0,$0,%0
+	andi	%0,0xffff
+	.set	at"
+	: "=r" (sum)
+	: "0" (daddr), "r"(saddr), "r"((ntohs(len)<<16)+proto*256), "r"(sum)
+	: "$1");
+
+	return (unsigned short)sum;
+}
+
+/*
+ *	Fold a partial checksum without adding pseudo headers
+ */
+static inline unsigned short int csum_fold(unsigned int sum)
+{
+    __asm__("
+	.set	noat
+	srl	$1,%0,16
+	addu	%0,$1
+	sltu	$1,%0,$1
+	nor	%0,$0,%0
+	andi	%0,0xffff
+	.set	at"
+	: "=r"(sum)
+	: "0" (sum)
+	: "$1");
+
+ 	return sum;
+}
+ 
+/*
+ * this routine is used for miscellaneous IP-like checksums, mainly
+ * in icmp.c
+ */
+static inline unsigned short ip_compute_csum(unsigned char * buff, int len) {
+    unsigned short int sum;
+
+    __asm__("
+	.set	noat
+	srl	$1,%0,16
+	addu	%0,$1
+	sltu	$1,%0,$1
+	nor	%0,$0,%0
+	andi	%0,0xffff
+	.set	at"
+	: "=r"(sum)
+	: "r" (csum_partial(buff, len, 0))
+	: "$1");
+
+	return sum;
+}
+
+#endif /* __ASM_MIPS_CHECKSUM_H */