Coding style: bit fields

Coding style: bit fields

[Giuliano Pochini]

The echoaudio driver has many flags in chip_t stored as bit fields. It
doesn't save any space because accessing a bitfield requires more
instructions than accessing a byte. Eg. ppc needs one instruction to write a
char and three instructions to write a bitfield (load, modify, store, 12
bytes...). I'm thinking about replacing all af them with chars. Is it ok ?



--
Giuliano.


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Re: Coding style: bit fields

[Takashi Iwai]

At Sat, 19 Feb 2005 18:37:26 +0100,
Giuliano Pochini wrote:
> 
> The echoaudio driver has many flags in chip_t stored as bit fields. It
> doesn't save any space because accessing a bitfield requires more
> instructions than accessing a byte. Eg. ppc needs one instruction to write a
> char and three instructions to write a bitfield (load, modify, store, 12
> bytes...). I'm thinking about replacing all af them with chars. Is it ok ?

Sure, go ahead!


Takashi


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Re: Coding style: bit fields

[Giuliano Pochini]

On Tue, 22 Feb 2005 22:04:08 +0100
Takashi Iwai <tiwai@suse.de> wrote:

> At Sat, 19 Feb 2005 18:37:26 +0100,
> Giuliano Pochini wrote:
> > 
> > The echoaudio driver has many flags in chip_t stored as bit fields. It
> > doesn't save any space because accessing a bitfield requires more
> > instructions than accessing a byte. Eg. ppc needs one instruction to write a
> > char and three instructions to write a bitfield (load, modify, store, 12
> > bytes...). I'm thinking about replacing all af them with chars. Is it ok ?
> 
> Sure, go ahead!

Fine.


Signed-off-by: Giuliano Pochini <pochini@shiny.it>

diff -du alsa-driver_orig/pci/echoaudio/echoaudio.h alsa-driver/pci/echoaudio/echoaudio.h
--- alsa-driver_orig/pci/echoaudio/echoaudio.h	Sat Feb 26 19:35:54 2005
+++ alsa-driver/pci/echoaudio/echoaudio.h	Sat Feb 26 12:57:18 2005
@@ -389,15 +389,15 @@
 	u8 input_clock;				/* Currently selected sample clock source */
 	u8 output_clock;			/* Layla20 only */
 
-	unsigned int meters_enabled : 1;	/* VU-meters status */
-	unsigned int asic_loaded : 1;		/* Set TRUE when ASIC loaded */
-	unsigned int bad_board : 1;		/* Set TRUE if DSP won't load */
-	unsigned int professional_spdif : 1;	/* 0 = consumer; 1 = professional */
-	unsigned int non_audio_spdif : 1;	/* 3G - only */
-	unsigned int digital_in_automute : 1;	/* Gina24, Layla24, Mona - only */
-	unsigned int phantom_power : 1;		/* Gina3G - only */
-	unsigned int has_midi : 1;
-	unsigned int midi_input_enabled : 1;
+	char meters_enabled;			/* VU-meters status */
+	char asic_loaded;			/* Set TRUE when ASIC loaded */
+	char bad_board;				/* Set TRUE if DSP won't load */
+	char professional_spdif;		/* 0 = consumer; 1 = professional */
+	char non_audio_spdif;			/* 3G - only */
+	char digital_in_automute;		/* Gina24, Layla24, Mona - only */
+	char phantom_power;			/* Gina3G - only */
+	char has_midi;
+	char midi_input_enabled;
 
 	char nominal_level[ECHO_MAXAUDIOPIPES];	/* True == -10dBV  False == +4dBu */
 	s8 input_gain[ECHO_MAXAUDIOINPUTS];	/* Input level -50..+50 unit is 0.5dB */



--
Giuliano.


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Re: Coding style: bit fields

[Takashi Iwai]

At Sat, 26 Feb 2005 19:59:18 +0100,
Giuliano Pochini wrote:
> 
> On Tue, 22 Feb 2005 22:04:08 +0100
> Takashi Iwai <tiwai@suse.de> wrote:
> 
> > At Sat, 19 Feb 2005 18:37:26 +0100,
> > Giuliano Pochini wrote:
> > > 
> > > The echoaudio driver has many flags in chip_t stored as bit fields. It
> > > doesn't save any space because accessing a bitfield requires more
> > > instructions than accessing a byte. Eg. ppc needs one instruction to write a
> > > char and three instructions to write a bitfield (load, modify, store, 12
> > > bytes...). I'm thinking about replacing all af them with chars. Is it ok ?
> > 
> > Sure, go ahead!
> 
> Fine.
> 
> 
> Signed-off-by: Giuliano Pochini <pochini@shiny.it>

Thanks, now it's on CVS.


Takashi


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