{Listing 1:  The DMT lookup function}

{
  Fn DYNAMIC requires a TypeOf() ptr and a dynamic index,
  and returns a method ptr or NIL.
}

function Dynamic(VMT: pointer; Index: word): pointer; assembler;
asm
	pushf			{Windows crashes if you diddle DF}
	std			{Scan backwards}
	mov	ax,[Index]	{Load the word we're searching for}
	les	di,[VMT]	{es:di points to VMT}
	mov	di,[es:di+4]	{Point to DMT, if any}
@Check:	or	di,di		{Test for DMT existence}
	jnz	@Exists
	mov	ax,di		{No DMT:  Return NIL}
	mov	dx,di
	jmp	@Exit
@Exists:
	mov	cx,[es:di+6]	{The length word}
	mov	bx,cx		{Make a copy}
	shl	bx,1		{Double it: word addressing}
	mov	si,di		{Retain a ptr to the DMT}
	lea	di,[di+bx+6]	{Offset of LAST dynamic index}
	repne	scasw		{Search for a match}
	jne	@NoMatch
@Match:	shl	cx,1		{Double the (origin 0) match index}
	shl	cx,1		{Double again, for dword indexing}
	add	bx,cx		{Add it to the `index list size'}
	les	ax,[es:si+bx+8] {@DMT+SizeOf(Indices}+SizeOf(Hdr) }
				{    +MatchIndex*SizeOf(pointer)  }
	mov	dx,es
	jmp	@Exit
@NoMatch:
	mov	di,[es:si]	{Offset of parent's DMT}
	jmp	@Check
@Exit:	popf			{Give Windows back its DF}
end;