Subject: Re: IBM405GP/GPr OPB bus_space endian (powerpc/ibm4xx/dev/opb.c)
To: Shigeyuki Fukushima <shige@NetBSD.org>
From: Tim Rightnour <root@garbled.net>
List: port-powerpc
Date: 03/12/2006 23:40:18
On 12-Mar-2006 Shigeyuki Fukushima wrote:
>>  static struct powerpc_bus_space opb_tag = {
>>       _BUS_SPACE_LITTLE_ENDIAN|_BUS_SPACE_MEM_TYPE,
>>       0x0, IBM405GP_UART0_BASE, 0x1000
>>  };
>> 
>> Why it is Little-Endian in spite of CPU byte-order (Big-Endian) ?
>> Is there any special reason?

My guess is that it was copied from port-prep.  Many of the ppc sub-ports were
copied from there.  It seems to work fine on prep.. but I haven't really
invesitgated why it's there.  (I assume it's part of the spec)

(though prep seems to have been copied from bebox...so.. maybe it originated
there.. dunno)

---
Tim Rightnour <root@garbled.net>
NetBSD: Free multi-architecture OS http://www.netbsd.org/
Genecys: Open Source 3D MMORPG: http://www.genecys.org/