461 строка
9.5 KiB
ArmAsm
461 строка
9.5 KiB
ArmAsm
/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* IP/TCP/UDP checksumming routines
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*
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* Authors: Jorge Cwik, <jorge@laser.satlink.net>
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* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
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* Tom May, <ftom@netcom.com>
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* Pentium Pro/II routines:
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* Alexander Kjeldaas <astor@guardian.no>
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* Finn Arne Gangstad <finnag@guardian.no>
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* Lots of code moved from tcp.c and ip.c; see those files
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* for more names.
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*
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* Changes: Ingo Molnar, converted csum_partial_copy() to 2.1 exception
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* handling.
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* Andi Kleen, add zeroing on error
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* converted to pure assembler
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/config.h>
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#include <asm/errno.h>
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/*
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* computes a partial checksum, e.g. for TCP/UDP fragments
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*/
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/*
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unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum)
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*/
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.text
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.align 4
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.globl csum_partial
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#ifndef CONFIG_X86_USE_PPRO_CHECKSUM
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/*
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* Experiments with Ethernet and SLIP connections show that buff
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* is aligned on either a 2-byte or 4-byte boundary. We get at
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* least a twofold speedup on 486 and Pentium if it is 4-byte aligned.
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* Fortunately, it is easy to convert 2-byte alignment to 4-byte
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* alignment for the unrolled loop.
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*/
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csum_partial:
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pushl %esi
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pushl %ebx
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movl 20(%esp),%eax # Function arg: unsigned int sum
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movl 16(%esp),%ecx # Function arg: int len
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movl 12(%esp),%esi # Function arg: unsigned char *buff
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testl $2, %esi # Check alignment.
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jz 2f # Jump if alignment is ok.
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subl $2, %ecx # Alignment uses up two bytes.
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jae 1f # Jump if we had at least two bytes.
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addl $2, %ecx # ecx was < 2. Deal with it.
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jmp 4f
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1: movw (%esi), %bx
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addl $2, %esi
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addw %bx, %ax
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adcl $0, %eax
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2:
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movl %ecx, %edx
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shrl $5, %ecx
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jz 2f
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testl %esi, %esi
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1: movl (%esi), %ebx
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adcl %ebx, %eax
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movl 4(%esi), %ebx
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adcl %ebx, %eax
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movl 8(%esi), %ebx
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adcl %ebx, %eax
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movl 12(%esi), %ebx
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adcl %ebx, %eax
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movl 16(%esi), %ebx
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adcl %ebx, %eax
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movl 20(%esi), %ebx
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adcl %ebx, %eax
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movl 24(%esi), %ebx
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adcl %ebx, %eax
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movl 28(%esi), %ebx
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adcl %ebx, %eax
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lea 32(%esi), %esi
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dec %ecx
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jne 1b
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adcl $0, %eax
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2: movl %edx, %ecx
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andl $0x1c, %edx
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je 4f
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shrl $2, %edx # This clears CF
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3: adcl (%esi), %eax
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lea 4(%esi), %esi
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dec %edx
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jne 3b
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adcl $0, %eax
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4: andl $3, %ecx
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jz 7f
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cmpl $2, %ecx
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jb 5f
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movw (%esi),%cx
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leal 2(%esi),%esi
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je 6f
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shll $16,%ecx
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5: movb (%esi),%cl
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6: addl %ecx,%eax
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adcl $0, %eax
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7:
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popl %ebx
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popl %esi
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ret
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#else
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/* Version for PentiumII/PPro */
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csum_partial:
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pushl %esi
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pushl %ebx
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movl 20(%esp),%eax # Function arg: unsigned int sum
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movl 16(%esp),%ecx # Function arg: int len
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movl 12(%esp),%esi # Function arg: const unsigned char *buf
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testl $2, %esi
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jnz 30f
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10:
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movl %ecx, %edx
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movl %ecx, %ebx
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andl $0x7c, %ebx
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shrl $7, %ecx
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addl %ebx,%esi
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shrl $2, %ebx
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negl %ebx
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lea 45f(%ebx,%ebx,2), %ebx
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testl %esi, %esi
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jmp *%ebx
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# Handle 2-byte-aligned regions
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20: addw (%esi), %ax
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lea 2(%esi), %esi
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adcl $0, %eax
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jmp 10b
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30: subl $2, %ecx
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ja 20b
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je 32f
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movzbl (%esi),%ebx # csumming 1 byte, 2-aligned
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addl %ebx, %eax
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adcl $0, %eax
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jmp 80f
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32:
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addw (%esi), %ax # csumming 2 bytes, 2-aligned
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adcl $0, %eax
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jmp 80f
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40:
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addl -128(%esi), %eax
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adcl -124(%esi), %eax
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adcl -120(%esi), %eax
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adcl -116(%esi), %eax
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adcl -112(%esi), %eax
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adcl -108(%esi), %eax
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adcl -104(%esi), %eax
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adcl -100(%esi), %eax
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adcl -96(%esi), %eax
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adcl -92(%esi), %eax
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adcl -88(%esi), %eax
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adcl -84(%esi), %eax
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adcl -80(%esi), %eax
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adcl -76(%esi), %eax
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adcl -72(%esi), %eax
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adcl -68(%esi), %eax
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adcl -64(%esi), %eax
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adcl -60(%esi), %eax
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adcl -56(%esi), %eax
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adcl -52(%esi), %eax
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adcl -48(%esi), %eax
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adcl -44(%esi), %eax
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adcl -40(%esi), %eax
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adcl -36(%esi), %eax
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adcl -32(%esi), %eax
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adcl -28(%esi), %eax
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adcl -24(%esi), %eax
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adcl -20(%esi), %eax
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adcl -16(%esi), %eax
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adcl -12(%esi), %eax
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adcl -8(%esi), %eax
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adcl -4(%esi), %eax
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45:
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lea 128(%esi), %esi
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adcl $0, %eax
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dec %ecx
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jge 40b
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movl %edx, %ecx
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50: andl $3, %ecx
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jz 80f
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# Handle the last 1-3 bytes without jumping
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notl %ecx # 1->2, 2->1, 3->0, higher bits are masked
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movl $0xffffff,%ebx # by the shll and shrl instructions
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shll $3,%ecx
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shrl %cl,%ebx
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andl -128(%esi),%ebx # esi is 4-aligned so should be ok
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addl %ebx,%eax
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adcl $0,%eax
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80:
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popl %ebx
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popl %esi
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ret
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#endif
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/*
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unsigned int csum_partial_copy_generic (const char *src, char *dst,
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int len, int sum, int *src_err_ptr, int *dst_err_ptr)
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*/
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/*
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* Copy from ds while checksumming, otherwise like csum_partial
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*
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* The macros SRC and DST specify the type of access for the instruction.
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* thus we can call a custom exception handler for all access types.
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*
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* FIXME: could someone double-check whether I haven't mixed up some SRC and
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* DST definitions? It's damn hard to trigger all cases. I hope I got
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* them all but there's no guarantee.
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*/
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#define SRC(y...) \
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9999: y; \
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.section __ex_table, "a"; \
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.long 9999b, 6001f ; \
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.previous
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#define DST(y...) \
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9999: y; \
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.section __ex_table, "a"; \
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.long 9999b, 6002f ; \
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.previous
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.align 4
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.globl csum_partial_copy_generic_i386
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#ifndef CONFIG_X86_USE_PPRO_CHECKSUM
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#define ARGBASE 16
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#define FP 12
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csum_partial_copy_generic_i386:
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subl $4,%esp
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pushl %edi
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pushl %esi
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pushl %ebx
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movl ARGBASE+16(%esp),%eax # sum
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movl ARGBASE+12(%esp),%ecx # len
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movl ARGBASE+4(%esp),%esi # src
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movl ARGBASE+8(%esp),%edi # dst
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testl $2, %edi # Check alignment.
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jz 2f # Jump if alignment is ok.
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subl $2, %ecx # Alignment uses up two bytes.
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jae 1f # Jump if we had at least two bytes.
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addl $2, %ecx # ecx was < 2. Deal with it.
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jmp 4f
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SRC(1: movw (%esi), %bx )
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addl $2, %esi
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DST( movw %bx, (%edi) )
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addl $2, %edi
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addw %bx, %ax
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adcl $0, %eax
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2:
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movl %ecx, FP(%esp)
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shrl $5, %ecx
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jz 2f
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testl %esi, %esi
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SRC(1: movl (%esi), %ebx )
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SRC( movl 4(%esi), %edx )
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adcl %ebx, %eax
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DST( movl %ebx, (%edi) )
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adcl %edx, %eax
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DST( movl %edx, 4(%edi) )
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SRC( movl 8(%esi), %ebx )
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SRC( movl 12(%esi), %edx )
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adcl %ebx, %eax
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DST( movl %ebx, 8(%edi) )
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adcl %edx, %eax
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DST( movl %edx, 12(%edi) )
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SRC( movl 16(%esi), %ebx )
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SRC( movl 20(%esi), %edx )
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adcl %ebx, %eax
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DST( movl %ebx, 16(%edi) )
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adcl %edx, %eax
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DST( movl %edx, 20(%edi) )
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SRC( movl 24(%esi), %ebx )
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SRC( movl 28(%esi), %edx )
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adcl %ebx, %eax
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DST( movl %ebx, 24(%edi) )
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adcl %edx, %eax
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DST( movl %edx, 28(%edi) )
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lea 32(%esi), %esi
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lea 32(%edi), %edi
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dec %ecx
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jne 1b
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adcl $0, %eax
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2: movl FP(%esp), %edx
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movl %edx, %ecx
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andl $0x1c, %edx
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je 4f
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shrl $2, %edx # This clears CF
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SRC(3: movl (%esi), %ebx )
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adcl %ebx, %eax
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DST( movl %ebx, (%edi) )
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lea 4(%esi), %esi
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lea 4(%edi), %edi
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dec %edx
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jne 3b
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adcl $0, %eax
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4: andl $3, %ecx
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jz 7f
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cmpl $2, %ecx
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jb 5f
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SRC( movw (%esi), %cx )
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leal 2(%esi), %esi
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DST( movw %cx, (%edi) )
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leal 2(%edi), %edi
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je 6f
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shll $16,%ecx
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SRC(5: movb (%esi), %cl )
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DST( movb %cl, (%edi) )
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6: addl %ecx, %eax
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adcl $0, %eax
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7:
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5000:
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# Exception handler:
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.section .fixup, "ax"
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6001:
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movl ARGBASE+20(%esp), %ebx # src_err_ptr
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movl $-EFAULT, (%ebx)
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# zero the complete destination - computing the rest
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# is too much work
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movl ARGBASE+8(%esp), %edi # dst
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movl ARGBASE+12(%esp), %ecx # len
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xorl %eax,%eax
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rep ; stosb
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jmp 5000b
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6002:
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movl ARGBASE+24(%esp), %ebx # dst_err_ptr
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movl $-EFAULT,(%ebx)
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jmp 5000b
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.previous
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popl %ebx
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popl %esi
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popl %edi
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popl %ecx # equivalent to addl $4,%esp
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ret
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#else
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/* Version for PentiumII/PPro */
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#define ROUND1(x) \
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SRC(movl x(%esi), %ebx ) ; \
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addl %ebx, %eax ; \
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DST(movl %ebx, x(%edi) ) ;
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#define ROUND(x) \
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SRC(movl x(%esi), %ebx ) ; \
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adcl %ebx, %eax ; \
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DST(movl %ebx, x(%edi) ) ;
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#define ARGBASE 12
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csum_partial_copy_generic_i386:
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pushl %ebx
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pushl %edi
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pushl %esi
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movl ARGBASE+4(%esp),%esi #src
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movl ARGBASE+8(%esp),%edi #dst
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movl ARGBASE+12(%esp),%ecx #len
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movl ARGBASE+16(%esp),%eax #sum
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# movl %ecx, %edx
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movl %ecx, %ebx
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movl %esi, %edx
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shrl $6, %ecx
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andl $0x3c, %ebx
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negl %ebx
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subl %ebx, %esi
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subl %ebx, %edi
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lea -1(%esi),%edx
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andl $-32,%edx
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lea 3f(%ebx,%ebx), %ebx
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testl %esi, %esi
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jmp *%ebx
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1: addl $64,%esi
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addl $64,%edi
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SRC(movb -32(%edx),%bl) ; SRC(movb (%edx),%bl)
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ROUND1(-64) ROUND(-60) ROUND(-56) ROUND(-52)
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ROUND (-48) ROUND(-44) ROUND(-40) ROUND(-36)
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ROUND (-32) ROUND(-28) ROUND(-24) ROUND(-20)
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ROUND (-16) ROUND(-12) ROUND(-8) ROUND(-4)
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3: adcl $0,%eax
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addl $64, %edx
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dec %ecx
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jge 1b
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4: movl ARGBASE+12(%esp),%edx #len
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andl $3, %edx
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jz 7f
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cmpl $2, %edx
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jb 5f
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SRC( movw (%esi), %dx )
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leal 2(%esi), %esi
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DST( movw %dx, (%edi) )
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leal 2(%edi), %edi
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je 6f
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shll $16,%edx
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5:
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SRC( movb (%esi), %dl )
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DST( movb %dl, (%edi) )
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6: addl %edx, %eax
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adcl $0, %eax
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7:
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.section .fixup, "ax"
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6001: movl ARGBASE+20(%esp), %ebx # src_err_ptr
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movl $-EFAULT, (%ebx)
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# zero the complete destination (computing the rest is too much work)
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movl ARGBASE+8(%esp),%edi # dst
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movl ARGBASE+12(%esp),%ecx # len
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xorl %eax,%eax
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rep; stosb
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jmp 7b
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6002: movl ARGBASE+24(%esp), %ebx # dst_err_ptr
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movl $-EFAULT, (%ebx)
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jmp 7b
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.previous
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popl %esi
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popl %edi
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popl %ebx
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ret
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#undef ROUND
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#undef ROUND1
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#endif
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