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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [mips/] [lib/] [checksum.c] - Blame information for rev 1777

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/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              MIPS specific IP/TCP/UDP checksumming routines
 *
 * Authors:     Ralf Baechle, <ralf@waldorf-gmbh.de>
 *              Lots of code moved from tcp.c and ip.c; see those files
 *              for more names.
 *
 *              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.
 */
#include <net/checksum.h>
#include <asm/string.h>
 
/*
 * computes a partial checksum, e.g. for TCP/UDP fragments
 */
 
unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum)
{
        unsigned long   scratch1;
        unsigned long   scratch2;
 
        /*
         * The GCC generated code for handling carry bits makes
         * it strongly desirable to do this in assembler!
         */
    __asm__("
        .set    noreorder
        .set    noat
        andi    $1,%5,2         # Check alignment
        beqz    $1,2f           # Branch if ok
        subu    $1,%4,2         # delay slot, Alignment uses up two bytes
        bgez    $1,1f           # Jump if we had at least two bytes
        move    %4,$1           # delay slot
        j       4f
        addiu   %4,2            # delay slot; len was < 2.  Deal with it
 
1:      lw      %2,(%5)
        addiu   %4,2
        addu    %0,%2
        sltu    $1,%0,%2
        addu    %0,$1
 
2:      move    %1,%4
        srl     %1,%1,5
        beqz    %1,2f
        sll     %1,%1,5         # delay slot
 
        addu    %1,%5
1:      lw      %2,0(%5)
        addu    %5,32
        addu    %0,%2
        sltu    $1,%0,%2
 
        lw      %2,-28(%5)
        addu    %0,$1
        addu    %0,%2
        sltu    $1,%0,%2
 
        lw      %2,-24(%5)
        addu    %0,$1
        addu    %0,%2
        sltu    $1,%0,%2
 
        lw      %2,-20(%5)
        addu    %0,$1
        addu    %0,%2
        sltu    $1,%0,%2
 
        lw      %2,-16(%5)
        addu    %0,$1
        addu    %0,%2
        sltu    $1,%0,%2
 
        lw      %2,-12(%5)
        addu    %0,$1
        addu    %0,%2
        sltu    $1,%0,%2
 
        lw      %2,-8(%5)
        addu    %0,$1
        addu    %0,%2
        sltu    $1,%0,%2
 
        lw      %2,-4(%5)
        addu    %0,$1
        addu    %0,%2
        sltu    $1,%0,%2
 
        bne     %5,%1,1b
        addu    %0,$1           # delay slot
 
2:      andi    %1,%4,0x1c
        srl     %1,%1,2
        beqz    %1,4f
        addu    %1,%5           # delay slot
3:      lw      %2,0(%5)
        addu    %5,4
        addu    %0,%2
        sltu    $1,%0,%2
        bne     %5,%1,3b
        addu    %0,$1           # delay slot
 
4:      andi    $1,%3,2
        beqz    $1,5f
        move    %2,$0           # delay slot
        lhu     %2,(%5)
        addiu   %5,2
 
5:      andi    $1,%3,1
        beqz    $1,6f
        sll     %1,16           # delay slot
        lbu     %1,(%5)
        nop                     # NOP ALERT (spit, gasp)
6:      or      %2,%1
        addu    %0,%2
        sltu    $1,%0,%2
        addu    %0,$1
7:      .set    at
        .set    reorder"
        : "=r"(sum), "=r" (scratch1), "=r" (scratch2)
        : "0"(sum), "r"(len), "r"(buff)
        : "$1");
 
        return sum;
}
 
/*
 * copy from fs while checksumming, otherwise like csum_partial
 */
unsigned int csum_partial_copy(const char *src, char *dst,
                                  int len, int sum)
{
        /*
         * It's 2:30 am and I don't feel like doing it real ...
         * This is lots slower than the real thing (tm)
         */
        sum = csum_partial(src, len, sum);
        memcpy(dst, src, len);
 
        return sum;
}

Line No.	Rev	Author	Line
1	1624	jcastillo	`/*`
2			`* INET An implementation of the TCP/IP protocol suite for the LINUX`
3			`* operating system. INET is implemented using the BSD Socket`
4			`* interface as the means of communication with the user level.`
5			`*`
6			`* MIPS specific IP/TCP/UDP checksumming routines`
7			`*`
8			`* Authors: Ralf Baechle, <ralf@waldorf-gmbh.de>`
9			`* Lots of code moved from tcp.c and ip.c; see those files`
10			`* for more names.`
11			`*`
12			`* This program is free software; you can redistribute it and/or`
13			`* modify it under the terms of the GNU General Public License`
14			`* as published by the Free Software Foundation; either version`
15			`* 2 of the License, or (at your option) any later version.`
16			`*/`
17			`#include <net/checksum.h>`
18			`#include <asm/string.h>`
19
20			`/*`
21			`* computes a partial checksum, e.g. for TCP/UDP fragments`
22			`*/`
23
24			`unsigned int csum_partial(const unsigned char *buff, int len, unsigned int sum)`
25			`{`
26			`unsigned long scratch1;`
27			`unsigned long scratch2;`
28
29			`/*`
30			`* The GCC generated code for handling carry bits makes`
31			`* it strongly desirable to do this in assembler!`
32			`*/`
33			`__asm__("`
34			`.set noreorder`
35			`.set noat`
36			`andi $1,%5,2 # Check alignment`
37			`beqz $1,2f # Branch if ok`
38			`subu $1,%4,2 # delay slot, Alignment uses up two bytes`
39			`bgez $1,1f # Jump if we had at least two bytes`
40			`move %4,$1 # delay slot`
41			`j 4f`
42			`addiu %4,2 # delay slot; len was < 2. Deal with it`
43
44			`1: lw %2,(%5)`
45			`addiu %4,2`
46			`addu %0,%2`
47			`sltu $1,%0,%2`
48			`addu %0,$1`
49
50			`2: move %1,%4`
51			`srl %1,%1,5`
52			`beqz %1,2f`
53			`sll %1,%1,5 # delay slot`
54
55			`addu %1,%5`
56			`1: lw %2,0(%5)`
57			`addu %5,32`
58			`addu %0,%2`
59			`sltu $1,%0,%2`
60
61			`lw %2,-28(%5)`
62			`addu %0,$1`
63			`addu %0,%2`
64			`sltu $1,%0,%2`
65
66			`lw %2,-24(%5)`
67			`addu %0,$1`
68			`addu %0,%2`
69			`sltu $1,%0,%2`
70
71			`lw %2,-20(%5)`
72			`addu %0,$1`
73			`addu %0,%2`
74			`sltu $1,%0,%2`
75
76			`lw %2,-16(%5)`
77			`addu %0,$1`
78			`addu %0,%2`
79			`sltu $1,%0,%2`
80
81			`lw %2,-12(%5)`
82			`addu %0,$1`
83			`addu %0,%2`
84			`sltu $1,%0,%2`
85
86			`lw %2,-8(%5)`
87			`addu %0,$1`
88			`addu %0,%2`
89			`sltu $1,%0,%2`
90
91			`lw %2,-4(%5)`
92			`addu %0,$1`
93			`addu %0,%2`
94			`sltu $1,%0,%2`
95
96			`bne %5,%1,1b`
97			`addu %0,$1 # delay slot`
98
99			`2: andi %1,%4,0x1c`
100			`srl %1,%1,2`
101			`beqz %1,4f`
102			`addu %1,%5 # delay slot`
103			`3: lw %2,0(%5)`
104			`addu %5,4`
105			`addu %0,%2`
106			`sltu $1,%0,%2`
107			`bne %5,%1,3b`
108			`addu %0,$1 # delay slot`
109
110			`4: andi $1,%3,2`
111			`beqz $1,5f`
112			`move %2,$0 # delay slot`
113			`lhu %2,(%5)`
114			`addiu %5,2`
115
116			`5: andi $1,%3,1`
117			`beqz $1,6f`
118			`sll %1,16 # delay slot`
119			`lbu %1,(%5)`
120			`nop # NOP ALERT (spit, gasp)`
121			`6: or %2,%1`
122			`addu %0,%2`
123			`sltu $1,%0,%2`
124			`addu %0,$1`
125			`7: .set at`
126			`.set reorder"`
127			`: "=r"(sum), "=r" (scratch1), "=r" (scratch2)`
128			`: "0"(sum), "r"(len), "r"(buff)`
129			`: "$1");`
130
131			`return sum;`
132			`}`
133
134			`/*`
135			`* copy from fs while checksumming, otherwise like csum_partial`
136			`*/`
137			`unsigned int csum_partial_copy(const char src, char dst,`
138			`int len, int sum)`
139			`{`
140			`/*`
141			`* It's 2:30 am and I don't feel like doing it real ...`
142			`* This is lots slower than the real thing (tm)`
143			`*/`
144			`sum = csum_partial(src, len, sum);`
145			`memcpy(dst, src, len);`
146
147			`return sum;`
148			`}`

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[/] [or1k/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [mips/] [lib/] [checksum.c] - Blame information for rev 1777