🚀 go-pugleaf

Robert AH Prins <mailto:prinsra@williscorroon.com> said: 

>To avoid having to load pointers over and over again, the program uses a
>GETMEM'ed array, I use BASM, and this works without a glitch, until...
>I had to change the size of the elements from 8 to 16 and didn't realize
>that I also needed to change a "shl  cx, 3" into "shl  cx, 4". I spend
>ages trying to find out what was wrong - the equivalent code in Pascal
>continued to work, be it rather more slowly.
>
>Does anyone know, short of what I've done now, adding a constant with
>the required shift value, if there is a way to get the base-2 log of
>sizes of datastructures in BASM. (Obviously restricted to sizes that are
>powers of 2...)
>
I can only think of two easy ways to do it as you cannot use SizeOf in
BASM :

1. In your startup program code get the SizeOf the data element into a
global variable and, if being used for shifts, convert to the relevant
power of two. You can just load this into CL for your shifts - as
SHL <register>, CL

2. Declare two dummy global variables the same size as one data element
immediately after each other and use BASM to get load the memory offset
of each into variables then use SUB to get the memory size. You'll still
need to SHL <register>, CL

HTH
-- 
Pedt

Veni; Vidi; Visa ... I came, I saw, I did a little shopping