patch-2.1.51 linux/arch/ppc/lib/checksum.S

• Lines: 193
• Date: Sat Aug 16 09:51:08 1997
• Orig file: v2.1.50/linux/arch/ppc/lib/checksum.S
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.50/linux/arch/ppc/lib/checksum.S linux/arch/ppc/lib/checksum.S
@@ -0,0 +1,192 @@
+/*
+ * This file contains assembly-language implementations
+ * of IP-style 1's complement checksum routines.
+ *	
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ * Severely hacked about by Paul Mackerras (paulus@cs.anu.edu.au).
+ */
+
+#include <linux/sys.h>
+#include <asm/errno.h>
+#include "../kernel/ppc_asm.tmpl"
+
+_TEXT()
+
+/*
+ * ip_fast_csum(buf, len) -- Optimized for IP header
+ * len is in words and is always >= 5.
+ */
+_GLOBAL(ip_fast_csum)
+	lwz	r0,0(r3)
+	lwzu	r5,4(r3)
+	addi	r4,r4,-2
+	addc	r0,r0,r5
+	mtctr	r4
+1:	lwzu	r4,4(r3)
+	adde	r0,r0,r4
+	bdnz	1b
+	addze	r0,r0		/* add in final carry */
+	rlwinm	r3,r0,16,0,31	/* fold two halves together */
+	add	r3,r0,r3
+	not	r3,r3
+	srwi	r3,r3,16
+	blr
+
+/*
+ * Compute checksum of TCP or UDP pseudo-header:
+ *   csum_tcpudp_magic(saddr, daddr, len, proto, sum)
+ */	
+_GLOBAL(csum_tcpudp_magic)
+	rlwimi	r5,r6,16,0,15	/* put proto in upper half of len */
+	addc	r0,r3,r4	/* add 4 32-bit words together */
+	adde	r0,r0,r5
+	adde	r0,r0,r7
+	addze	r0,r0		/* add in final carry */
+	rlwinm	r3,r0,16,0,31	/* fold two halves together */
+	add	r3,r0,r3
+	not	r3,r3
+	srwi	r3,r3,16
+	blr
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * csum_partial(buff, len, sum)
+ */
+_GLOBAL(csum_partial)
+	addic	r0,r5,0
+	subi	r3,r3,4
+	srwi.	r6,r4,2
+	beq	3f		/* if we're doing < 4 bytes */
+	andi.	r5,r3,2		/* Align buffer to longword boundary */
+	beq+	1f
+	lhz	r5,4(r3)	/* do 2 bytes to get aligned */
+	addi	r3,r3,2
+	subi	r4,r4,2
+	addc	r0,r0,r5
+	srwi.	r6,r4,2		/* # words to do */
+	beq	3f
+1:	mtctr	r6
+2:	lwzu	r5,4(r3)	/* the bdnz has zero overhead, so it should */
+	adde	r0,r0,r5	/* be unnecessary to unroll this loop */
+	bdnz	2b
+	andi.	r4,r4,3
+3:	cmpi	0,r4,2
+	blt+	4f
+	lhz	r5,4(r3)
+	addi	r3,r3,2
+	subi	r4,r4,2
+	adde	r0,r0,r5
+4:	cmpi	0,r4,1
+	bne+	5f
+	lbz	r5,4(r3)
+	slwi	r5,r5,8		/* Upper byte of word */
+	adde	r0,r0,r5
+5:	addze	r3,r0		/* add in final carry */
+	blr
+
+/*
+ * Computes the checksum of a memory block at src, length len,
+ * and adds in "sum" (32-bit), while copying the block to dst.
+ * If an access exception occurs on src or dst, it stores -EFAULT
+ * to *src_err or *dst_err respectively, and (for an error on
+ * src) zeroes the rest of dst.
+ *
+ * csum_partial_copy_generic(src, dst, len, sum, src_err, dst_err)
+ */
+_GLOBAL(csum_partial_copy_generic)
+	addic	r0,r6,0
+	subi	r3,r3,4
+	subi	r4,r4,4
+	srwi.	r6,r5,2
+	beq	3f		/* if we're doing < 4 bytes */
+	andi.	r9,r4,2		/* Align dst to longword boundary */
+	beq+	1f
+81:	lhz	r6,4(r3)	/* do 2 bytes to get aligned */
+	addi	r3,r3,2
+	subi	r5,r5,2
+91:	sth	r6,4(r4)
+	addi	r4,r4,2
+	addc	r0,r0,r6
+	srwi.	r6,r5,2		/* # words to do */
+	beq	3f
+1:	mtctr	r6
+82:	lwzu	r6,4(r3)	/* the bdnz has zero overhead, so it should */
+92:	stwu	r6,4(r4)	/* be unnecessary to unroll this loop */
+	adde	r0,r0,r6
+	bdnz	82b
+	andi.	r5,r5,3
+3:	cmpi	0,r5,2
+	blt+	4f
+83:	lhz	r6,4(r3)
+	addi	r3,r3,2
+	subi	r5,r5,2
+93:	sth	r6,4(r4)
+	addi	r4,r4,2
+	adde	r0,r0,r6
+4:	cmpi	0,r5,1
+	bne+	5f
+84:	lbz	r6,4(r3)
+94:	stb	r6,4(r4)
+	slwi	r6,r6,8		/* Upper byte of word */
+	adde	r0,r0,r6
+5:	addze	r3,r0		/* add in final carry */
+	blr
+
+.section .fixup,"ax"
+
+src_error_1:
+	li	r6,0
+	subi	r5,r5,2
+95:	sth	r6,4(r4)
+	addi	r4,r4,2
+	srwi.	r6,r5,2
+	beq	3f
+	mtctr	r6
+src_error_2:
+	li	r6,0
+96:	stwu	r6,4(r4)
+	bdnz	96b
+3:	andi.	r5,r5,3
+	beq	src_error
+src_error_3:
+	li	r6,0
+	mtctr	r5
+	addi	r4,r4,3
+97:	stbu	r6,1(r4)
+	bdnz	97b
+src_error:
+	cmpi	0,r7,0
+	beq	1f
+	li	r6,-EFAULT
+	stw	r6,0(r7)
+1:	addze	r3,r0
+	blr
+
+dst_error:
+	cmpi	0,r8,0
+	beq	1f
+	li	r6,-EFAULT
+	stw	r6,0(r8)
+1:	addze	r3,r0
+	blr
+
+.section __ex_table,"a"
+	.long	81b,src_error_1
+	.long	91b,dst_error
+	.long	82b,src_error_2
+	.long	92b,dst_error
+	.long	83b,src_error_3
+	.long	93b,dst_error
+	.long	84b,src_error_3
+	.long	94b,dst_error
+	.long	95b,dst_error
+	.long	96b,dst_error
+	.long	97b,dst_error