Binary strings: Difference between revisions
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=={{header|8086 Assembly}}==
The 8086 has built-in support for handling byte and word strings, using <code>DS:SI</code> and <code>ES:DI</code> as the source and destination pointers, respectively. String functions can either auto-increment or auto-decrement the pointers held in these registers; the '''direction flag''' determines which one takes place. (<code>CLD</code> for auto-inc, <code>STD</code> for auto-dec.)
===Copying strings===
<lang asm>;this code assumes that both DS and ES point to the correct segments.
cld
mov si,offset TestMessage
mov di,offset EmptyRam
mov cx,5 ;length of the source string, you'll need to either know this
;ahead of time or calculate it.
rep movsb
ret
;there is no buffer overflow protection built into these functions so
;be careful!!!
TestMessage byte "Hello"
EmptyRam byte 0,0,0,0,0</lang>
===Checking if a particular byte exists===
<lang asm>;this code assumes that ES points to the correct segment.
cld
mov di,offset TestMessage
mov al,'o' ;the byte we wish to check
mov cx,5 ;len(Test)
repnz scasb ;scan through the string and stop if a match is found.
;flags will be set accordingly
ret
TestMessage byte "Hello"</lang>
===Compare two strings===
<lang asm>;this code assumes that both DS and ES point to the correct segments.
cld
mov si,offset foo
mov di,offset bar
mov cx,4 ;length of the shorter of the two.
repz cmpsb ;this will continue until the strings are different or CX = 0, whichever occurs first. If, after this, the zero flag is set and CX=0, the strings were the same.
ret
foo byte "test"
bar byte "test"</lang>
=={{header|Ada}}==
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