2 Questions

 BBS: Inland Empire Archive
Date: 02-14-93 (17:43)             Number: 163
From: DAVIDSON CORRY               Refer#: NONE
  To: MIKE KOST                     Recvd: NO  
Subj: 2 Questions                    Conf: (1) 80xxx

MK: What is the $ for? i've seen it used, and since i've learned by example
  :, without a good beginning tutor book, i never found out.

In many assemblers (particularly 80x86 assemblers, especially those whose
syntax derives from the Intel/MASM antecedents) the built-in symbol $
represents the current location counter.  That is, in

    JMP  $+3

the $ represents the offset of the JMP opcode.  In MASM-compatible
assemblers, a symbol has not only offset information associated with
it, but also type information.

$ is equivalent to THIS LABEL. THIS is a keyword meaning "at the current
offset within the current segment", and it takes a type argument:  BYTE,
WORD, DWORD... for data types, or LABEL for code targets.

For simplicity's sake, many of us read $ as the word "here".  Thus we'd
pronounce JMP $+3 as "jump here plus three" -- JMP to the location three
bytes beyond the offset of the JMP opcode.


--- Maximus 2.01wb
 * Origin: Cornerstone C,C++,Assy,Windows (206)362-4283 (1:343/22)