Re: A86: Optimization...

To: assembly-86@lists.ticalc.org
Subject: Re: A86: Optimization...
From: NSJ aka Viriato <nmasj@camoes.rnl.ist.utl.pt>
Date: Sat, 24 Apr 1999 18:01:27 +0100
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
Delivered-To: assembly-86@lists.ticalc.org
References: <00a101be8de8$d8f952e0$d346dacd@computername> <19990423.175621.11406.0.V8r@juno.com>
Reply-To: assembly-86@lists.ticalc.org

Chris Magill wrote:
>  ld hl,57*256+59                ;penrow=57,pencol=58
>  ld (_penCol),hl                ;set those coords
> 
> Is there any optimization difference between this and...
>  ld hl,393Bh
>  ld (_penCol),hl

  These two 'forms' are exactlly the same.  The assembler computes
  the value for "57*256+59" and assembles the instruction, which is
  a "load hl with constant". "ld hl,393Bh" is also the instruction
  which loads hl with a constant. Assemblers compute the value of
  constant expressions before actually assembling the instruction.
  57*256+59 simply is more readable then 393Bh. Just by looking at
  the first form you will know that it's position (57,59). By
  looking at the second form you will have to convert from hex to
  dec first.

  NSJ aka Viriato

References:

Re: A86: ABS -> ASIC

From: "JBrett" <tbarwick@esn.net>

A86: Optimization...

From: Chris Magill <v8r@juno.com>

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