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author Aaron Giles <aaron@aarongiles.com>2008-05-01 14:32:31 +0000
committer Aaron Giles <aaron@aarongiles.com>2008-05-01 14:32:31 +0000
commit67e76e92f573e40355a1a458b7e2f1ff49409c3c (patch)
treecf2947135430bff14202b62ce7f0a57c3d707131 /src/emu/sound/ay8910.c
parent37c56cf592dfc518ba511108566373958f81e377 (diff)
Cleanups/version bump.mame0124u5
Diffstat (limited to 'src/emu/sound/ay8910.c')
-rw-r--r--src/emu/sound/ay8910.c52
1 files changed, 26 insertions, 26 deletions
diff --git a/src/emu/sound/ay8910.c b/src/emu/sound/ay8910.c
index bc4f14fcebb..d3aa95b2749 100644
--- a/src/emu/sound/ay8910.c
+++ b/src/emu/sound/ay8910.c
@@ -71,28 +71,28 @@ offset of 1.5V and a VPP of 1.3V.
The following is documentation from the code moved here and amended to reflect
the changes done:
-
+
Careful studies of the chip output prove that the chip counts up from 0
-until the counter becomes greater or equal to the period. This is an
-important difference when the program is rapidly changing the period to
-modulate the sound. This is worthwhile noting, since the datasheets
+until the counter becomes greater or equal to the period. This is an
+important difference when the program is rapidly changing the period to
+modulate the sound. This is worthwhile noting, since the datasheets
say, that the chip counts down.
Also, note that period = 0 is the same as period = 1. This is mentioned
in the YM2203 data sheets. However, this does NOT apply to the Envelope
period. In that case, period = 0 is half as period = 1.
Envelope shapes:
- C AtAlH
- 0 0 x x \___
- 0 1 x x /___
- 1 0 0 0 \\\\
- 1 0 0 1 \___
- 1 0 1 0 \/\/
- 1 0 1 1 \```
- 1 1 0 0 ////
- 1 1 0 1 /```
- 1 1 1 0 /\/\
- 1 1 1 1 /___
+ C AtAlH
+ 0 0 x x \___
+ 0 1 x x /___
+ 1 0 0 0 \\\\
+ 1 0 0 1 \___
+ 1 0 1 0 \/\/
+ 1 0 1 1 \```
+ 1 1 0 0 ////
+ 1 1 0 1 /```
+ 1 1 1 0 /\/\
+ 1 1 1 1 /___
The envelope counter on the AY-3-8910 has 16 steps. On the YM2149 it
has twice the steps, happening twice as fast.
@@ -190,7 +190,7 @@ struct _ay8910_context
/*************************************
*
- * Static
+ * Static
*
*************************************/
@@ -262,7 +262,7 @@ static const ay_ym_param ay8910_param =
/*************************************
*
- * Inline
+ * Inline
*
*************************************/
@@ -379,7 +379,7 @@ INLINE UINT16 mix_3D(ay8910_context *psg)
/*************************************
*
- * Static functions
+ * Static functions
*
*************************************/
@@ -546,7 +546,7 @@ static void ay8910_update(void *param,stream_sample_t **inputs, stream_sample_t
if (psg->holding == 0)
{
psg->count_env++;
- if (psg->count_env >= ENVELOPE_PERIOD(psg) * psg->step )
+ if (psg->count_env >= ENVELOPE_PERIOD(psg) * psg->step )
{
psg->count_env = 0;
psg->env_step--;
@@ -619,9 +619,9 @@ static void build_mixer_table(ay8910_context *psg)
build_single_table(psg->intf->res_load[chan], psg->par_env, normalize, psg->env_table[chan], 0);
}
/*
- * The previous implementation added all three channels up instead of averaging them.
- * The factor of 3 will force the same levels if normalizing is used.
- */
+ * The previous implementation added all three channels up instead of averaging them.
+ * The factor of 3 will force the same levels if normalizing is used.
+ */
build_3D_table(psg->intf->res_load[0], psg->par, psg->par_env, normalize, 3, psg->zero_is_off, psg->vol3d_table);
}
@@ -650,8 +650,8 @@ static void ay8910_statesave(ay8910_context *psg, int sndindex)
/*************************************
*
- * Public functions
- *
+ * Public functions
+ *
* used by e.g. YM2203, YM2210 ...
*
*************************************/
@@ -812,7 +812,7 @@ int ay8910_read_ym(void *chip)
/*************************************
*
* Sound Interface
- *
+ *
*************************************/
static void *ay8910_start(int sndindex, int clock, const void *config)
@@ -947,7 +947,7 @@ void ymz294_get_info(void *token, UINT32 state, sndinfo *info)
/*************************************
*
* Read/Write Handlers
- *
+ *
*************************************/
READ8_HANDLER( AY8910_read_port_0_r ) { return ay8910_read_ym(sndti_token(SOUND_AY8910, 0)); }