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100 lines
2.8 KiB
ArmAsm
100 lines
2.8 KiB
ArmAsm
#include <asm.inc>
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#if 0
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page ,132
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title strnset - set first n characters to one char.
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;***
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;strnset.asm - set first n characters to single character
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;
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; Copyright (c) Microsoft Corporation. All rights reserved.
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;
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;Purpose:
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; defines _strnset() - sets at most the first n characters of a string
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; to a given character.
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;
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;*******************************************************************************
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.xlist
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include cruntime.inc
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.list
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page
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;***
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;char *_strnset(string, val, count) - set at most count characters to val
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;
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;Purpose:
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; Sets the first count characters of string the character value.
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; If the length of string is less than count, the length of
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; string is used in place of n.
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;
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; Algorithm:
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; char *
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; _strnset (string, val, count)
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; char *string,val;
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; unsigned int count;
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; {
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; char *start = string;
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;
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; while (count-- && *string)
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; *string++ = val;
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; return(start);
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; }
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;
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;Entry:
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; char *string - string to set characters in
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; char val - character to fill with
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; unsigned count - count of characters to fill
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;
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;Exit:
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; returns string, now filled with count copies of val.
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;
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;Uses:
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;
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;Exceptions:
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;
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;*******************************************************************************
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#endif
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.code
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public __strnset
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.PROC __strnset
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// Prolog. Original sources used ML's extended PROC feature to autogenerate this.
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push ebp
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mov ebp, esp
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push edi // uses edi ebx
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push ebx
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#define string ebp + 8 // string:ptr byte
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#define val ebp + 12 // val:byte
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#define count ebp + 16 // count:IWORD
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mov edi,[string] // di = string
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mov edx,edi // dx=string addr; save return value
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mov ebx,[count] // cx = max chars to set
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xor eax,eax // null byte
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mov ecx,ebx
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jecxz short done // zero length specified
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repne scasb // find null byte & count bytes in cx
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jne short nonull // null not found
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add ecx,1 // don't want the null
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nonull:
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sub ebx,ecx // bx=strlen (not null)
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mov ecx,ebx // cx=strlen (not null)
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mov edi,edx // restore string pointer
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mov al,[val] // byte value
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rep stosb // fill 'er up
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done:
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mov eax,edx // return value: string addr
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// Epilog. Original sources used ML's extended PROC feature to autogenerate this.
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pop ebx
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pop edi
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pop ebp
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ret // _cdecl return
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.ENDP // __strnset
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end
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