Re: [BLACKBOX] Another (?) Compiler Trap

From: Campbell, Robert (SELEX GALILEO, UK) <"Campbell,>
Date: Mon, 3 Mar 2008 10:22:30 -0000

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Hi

By total coincidence I came across another (possibly the same)
compiler TRAP this morning:

VAR
  x, z : REAL
  exp : INTEGER;
BEGIN
  z := ABS (x);
  exp := SHORT (ASH (SYSTEM.VAL (LONGINT, z), -52)) - 1023;


The code above works ok, but if I one-line it by replacing z by 'ABS
(x)' I get TRAP 0.



This code is an attempt to extract the exponent of a floating point
number.
I know that Math.Exponent already provides this function, but I am
trying to
get a version that will also run under the Gardens Point compiler.

The code above is NOT transportable because it uses SYSTEM.VAL. Chris,
if you are
listening, is there a Gardens Point way of type casting REALs to
LONGINTs without
changing the bit patterns?


Thanks

Robert

SELEX Sensors and Airborne Systems Limited
Registered Office: Sigma House, Christopher Martin Road, Basildon, Essex SS14 3EL
A company registered in England & Wales. Company no. 02426132
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Received on Mon Mar 03 2008 - 11:22:30 UTC