Re: read this promgram,please
- From: Tim Roberts <spamtrap@xxxxxxxxxx>
- Date: Tue, 24 Oct 2006 06:11:29 GMT
spamtrap@xxxxxxxxxx wrote:
what does " shl si,1 add si,di" do?
"mov si,es:[di]" fetches an index from the table. Since entries in the
table are two bytes wide, you have to multiple the index by 2 to get the
byte offset of that entry. "shl si,1" multiplies si by 2. "add si,di"
adds the address of the start of the table. When those 3 instructions are
done, es:[si] will contain the entry in the table at the index stored in
es:[di].
--
Tim Roberts, timr@xxxxxxxxx
Providenza & Boekelheide, Inc.
.
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