Re: Convert to float and more
Re: Convert to float and more
- Subject: Re: Convert to float and more
- From: Jose Commins <email@hidden>
- Date: Thu, 5 Jun 2003 22:05:14 +0100
If you don't like having your code waddle through the treacle that is
known as C++ while converting int to float, here's some PowerPC code to
perform int-to-float:
Input: r3 = int
Output fp1 = float
; Code
lfd fp4, itofloat(r7) ; Get the float -> float correcting constant.
xoris r8, r3, $8000
stw r8, -4(SP)
lis r8, 17200
stw r8, -8(SP)
lfd fp1, -8(SP)
fsub fp1,fp1,fp4
; Ta-da!
itofloat: dc.l $43300000, $80000000
Regards,
Jose.
On Wednesday, June 4, 2003, at 06:27 PM, Peter Mark wrote:
From: "Mark's Studio" <email@hidden>
Date: Wed Jun 4, 2003 9:46:54 AM Europe/London
To: email@hidden
Subject: Convert to float and more
Hi
I have a few questions.
Im working on a Cocoa sound editing app.
When i import a file i just copy the sound bytes into a NSData and keep
it in the original format.
All my drawing and DSP code use floats, so if the original sound format
is 16bit i do a lot of sample/32768.
I was thinking of converting the samples to float when importing the
file, but that will double the data size, so i still need to decide
what's best.
I tried to search the archives for the fastest way to convert from int
to float and back. but did not find much,
someone mentioned there might be a altivec snippet for converting?
I also looked at CASampleTools.cpp ( but to be honest i don't
understand C++).
When i play a file through the defaultAudioOutput, and the stream
format is not float, is there another conversion to float within
coreaudio?
I also want to import/export MP3 and other compressed formats what is
the best way to do that?
Thanks
Peter Mark
Mark's Recording Studio A/S
Lundeskovsvej 3 2900 Hellerup
Denmark
Tel: +45 35366078 Fax: +45 35366038
www.marks-studio.dk
email@hidden
--
The law of gravity says, "no fair jumping without coming down"
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