From: "Sergio Masci"
Subject: Re: new direct floating point support for PIC XCSB and associated tools
X-Newsreader: Microsoft Outlook Express 5.00.2615.200
Date: Fri, 18 Oct 2002 17:19:32 +0100
NNTP-Posting-Date: Fri, 18 Oct 2002 17:15:29 BST
Organization: ntlworld News Service
John Larkin wrote in message
> On Thu, 17 Oct 2002 16:04:06 +0100, "Sergio Masci"
> >The XCSB structured BASIC for the PIC now directly supports IEEE 754 32
> >floating point.
> What's the typical time to do a floating divide?
1.0 / 1.0 (where 1.0 is represented by the bit pattern 0x3f800000 )
= 419 machine cycles
1.33333 / 1.0 (where 1.33333 is represented by the bit pattern
= 1508 machine cycles
The time will be a function of the processor clock.
These times are for a 14 bit PIC core such as the 16F84, 16F628 and 16F877.
The machine code included in the timing was the full divide function
including pack, unpacking and exception handling. The worst case can
probably be improved at the cost of additional code space and temporary RAM.
XCSB produces a full assembler listing and binary executable (in Intel hex
format), this in conjunction with MPLAB will allows these timings to be