62 lines
1019 B
NASM
62 lines
1019 B
NASM
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; :ts=8
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;Copyright (C) 1983 by Manx Software Systems
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include lmacros.h
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procdef strncmp,<<str1,ptr>,<str2,ptr>,<len,word>>
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cld
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push si
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push di
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pushds
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mov cx,len
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test cx,cx
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jz equal
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mov dx,cx
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shr cx,1 ;# of times through word loop
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ldptr si,str1
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ifndef LONGPTR
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mov di,ds
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mov es,di
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endif
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ldptr di,str2
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jcxz words_equal
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ncmploop:
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lodsw
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scasw
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jne word_notequal
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test al,al
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jz equal
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test ah,ah
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loopnz ncmploop
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jz equal
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words_equal:
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test dl,1
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jz equal
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cmpsb
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jne notequal
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equal:
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sub ax,ax
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done:
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popds
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pop di
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pop si
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pret
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word_notequal:
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sub di,2 ;back up to first byte in word
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scasb ;and redo the compare a byte at a time
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jne notequal
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test al,al ;if end of string, this was a false mismatch
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jz equal
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mov al,ah ;get second byte
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scasb ;this must be not equal, since the words aren't equal
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notequal:
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sbb ax,ax
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js done ;if -1 then s1<s2 and we are done
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inc ax ;else, ==0 and s1>s2
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jmp done
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pend strncmp
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finish
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end
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