Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * 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 

#include 

#include 

#include 

/*

 * ip_fast_csum(r3=buf, r4=len) -- Optimized for IP header

 * len is in words and is always >= 5.

 *

 * In practice len == 5, but this is not guaranteed.  So this code does not

 * attempt to use doubleword instructions.

 */

_GLOBAL(ip_fast_csum)

        lwz     r0,0(r3)

        lwzu    r5,4(r3)

        addic.  r4,r4,-2

        addc    r0,r0,r5

        mtctr   r4

        blelr-

1:      lwzu    r4,4(r3)

        adde    r0,r0,r4

        bdnz    1b

        addze   r0,r0           /* add in final carry */

        rldicl  r4,r0,32,0      /* fold two 32-bit halves together */

        add     r0,r0,r4

        srdi    r0,r0,32

        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(r3=saddr, r4=daddr, r5=len, r6=proto, r7=sum)

 * No real gain trying to do this specially for 64 bit, but

 * the 32 bit addition may spill into the upper bits of

 * the doubleword so we still must fold it down from 64.

 */

_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

        rldicl  r4,r0,32,0      /* fold 64 bit value */

        add     r0,r4,r0

        srdi    r0,r0,32

        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).

 *

 * This code assumes at least halfword alignment, though the length

 * can be any number of bytes.  The sum is accumulated in r5.

 *

 * csum_partial(r3=buff, r4=len, r5=sum)

 */

_GLOBAL(csum_partial)

        subi    r3,r3,8         /* we'll offset by 8 for the loads */

        srdi.   r6,r4,3         /* divide by 8 for doubleword count */

        addic   r5,r5,0         /* clear carry */

        beq     3f              /* if we're doing < 8 bytes */

        andi.   r0,r3,2         /* aligned on a word boundary already? */

        beq+    1f

        lhz     r6,8(r3)        /* do 2 bytes to get aligned */

        addi    r3,r3,2

        subi    r4,r4,2

        addc    r5,r5,r6

        srdi.   r6,r4,3         /* recompute number of doublewords */

        beq     3f              /* any left? */

1:      mtctr   r6

2:      ldu     r6,8(r3)        /* main sum loop */

        adde    r5,r5,r6

        bdnz    2b

        andi.   r4,r4,7         /* compute bytes left to sum after doublewords */

3:      cmpwi   0,r4,4          /* is at least a full word left? */

        blt     4f

        lwz     r6,8(r3)        /* sum this word */

        addi    r3,r3,4

        subi    r4,r4,4

        adde    r5,r5,r6

4:      cmpwi   0,r4,2          /* is at least a halfword left? */

        blt+    5f

        lhz     r6,8(r3)        /* sum this halfword */

        addi    r3,r3,2

        subi    r4,r4,2

        adde    r5,r5,r6

5:      cmpwi   0,r4,1          /* is at least a byte left? */

        bne+    6f

        lbz     r6,8(r3)        /* sum this byte */

        slwi    r6,r6,8         /* this byte is assumed to be the upper byte of a halfword */

        adde    r5,r5,r6

6:      addze   r5,r5           /* add in final carry */

        rldicl  r4,r5,32,0      /* fold two 32-bit halves together */

        add     r3,r4,r5

        srdi    r3,r3,32

        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.

 *

 * This code needs to be reworked to take advantage of 64 bit sum+copy.

 * However, due to tokenring halfword alignment problems this will be very

 * tricky.  For now we'll leave it until we instrument it somehow.

 *

 * csum_partial_copy_generic(r3=src, r4=dst, r5=len, r6=sum, r7=src_err, r8=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:      cmpwi   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:      cmpwi   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 (unlikely with 64-bit regs) */

        rldicl  r4,r3,32,0      /* fold 64 bit value */

        add     r3,r4,r3

        srdi    r3,r3,32

        blr

/* These shouldn't go in the fixup section, since that would

   cause the ex_table addresses to get out of order. */

        .globl src_error_1

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

        .globl src_error_2

src_error_2:

        li      r6,0

96:     stwu    r6,4(r4)

        bdnz    96b

3:      andi.   r5,r5,3

        beq     src_error

        .globl src_error_3

src_error_3:

        li      r6,0

        mtctr   r5

        addi    r4,r4,3

97:     stbu    r6,1(r4)

        bdnz    97b

        .globl src_error

src_error:

        cmpdi   0,r7,0

        beq     1f

        li      r6,-EFAULT

        stw     r6,0(r7)

1:      addze   r3,r0

        blr

        .globl dst_error

dst_error:

        cmpdi   0,r8,0

        beq     1f

        li      r6,-EFAULT

        stw     r6,0(r8)

1:      addze   r3,r0

        blr

.section __ex_table,"a"

        .align  3

        .llong  81b,src_error_1

        .llong  91b,dst_error

        .llong  82b,src_error_2

        .llong  92b,dst_error

        .llong  83b,src_error_3

        .llong  93b,dst_error

        .llong  84b,src_error_3

        .llong  94b,dst_error

        .llong  95b,dst_error

        .llong  96b,dst_error

        .llong  97b,dst_error