109 lines
1.9 KiB
NASM
109 lines
1.9 KiB
NASM
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; crc_lcc.asm, optimized CRC calculation function for Zip and UnZip, not
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; copyrighted by Paul Kienitz and Christian Spieler. Last revised 25 Mar 98.
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;
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; The code in this file has been copied verbatim from crc_i386.{asm|S};
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; only the assembler syntax and metacommands have been adapted to
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; the habits of the free LCC-Win32 C compiler package.
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; This version of the code uses the "optimized for i686" variant of
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; crc_i386.{asm|S}.
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;
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; For more information (and a revision log), look into the original
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; source files.
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;
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.text
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.file "crc32.c"
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.text
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.type _crc32,function
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_crc32:
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pushl %ebp
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movl %esp,%ebp
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pushl %ecx
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pushl %ebx
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pushl %esi
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pushl %edi
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.line 34
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.line 37
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movl 12(%ebp),%esi
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subl %eax,%eax
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testl %esi,%esi
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jz _$3
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.line 39
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call _get_crc_table
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movl %eax,%edi
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.line 41
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movl 8(%ebp),%eax
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movl 16(%ebp),%ecx
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notl %eax
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testl %ecx,%ecx
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jz _$4
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_$5:
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testl $3,%esi
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jz _$6
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xorb (%esi),%al
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incl %esi
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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decl %ecx
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jnz _$5
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_$6:
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movl %ecx,%edx
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andl $7,%edx
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shrl $3,%ecx
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jz _$8
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_$7:
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xorl (%esi),%eax
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addl $4,%esi
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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xorl (%esi),%eax
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addl $4,%esi
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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decl %ecx
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jnz _$7
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_$8:
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movl %edx,%ecx
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jecxz _$4
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_$9:
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xorb (%esi),%al
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incl %esi
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movzbl %al,%ebx
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shrl $8,%eax
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xorl (%edi,%ebx,4),%eax
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decl %ecx
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jnz _$9
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_$4:
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xorl $0xffffffff,%eax
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_$3:
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.line 52
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popl %edi
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popl %esi
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popl %ebx
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leave
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ret
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_$34:
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.size _crc32,_$34-_crc32
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.globl _crc32
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.extern _get_crc_table
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