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beezer audio: got rid of sh6840_LFSR_oldxor, was leftover of old code. no whatsnew.

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Jonathan Gevaryahu 2011-02-05 23:40:14 +00:00
parent e6bf8f49f7
commit 259a401ad6
1 changed files with 3 additions and 8 deletions
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11
src/mame/audio/beezer.c
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@ -7,7 +7,6 @@
AKA Lord Nightmare
TODO:
* get rid of sh6840_LFSR_oldxor, is leftover of old code.
* Several inexplicable things on the schematic are not handled, such as the
'VCO' input for 6840 channel 2 external clock whose source does not appear
anywhere on the schematic, nor does it handle the 'DMOD DATA' and 'DMOD
@ -102,7 +101,6 @@ struct _beezer_sound_state
UINT8 sh6840_volume[4];
UINT8 sh6840_MSB_latch;
UINT8 sh6840_LSB_latch;
UINT8 sh6840_LFSR_oldxor;
UINT32 sh6840_LFSR;
UINT32 sh6840_LFSR_clocks;
UINT32 sh6840_clocks_per_sample;
@ -218,7 +216,6 @@ INLINE int sh6840_update_noise(beezer_sound_state *state, int clocks)
state->sh6840_LFSR_clocks = 0;
/* shift the LFSR. finally or in the result and see if we've
* had a 0->1 transition */
state->sh6840_LFSR_oldxor = state->sh6840_LFSR&0x1;
newxor = (((state->sh6840_LFSR&0x10000)?1:0) ^ ((state->sh6840_LFSR&0x2000)?1:0))?1:0;
state->sh6840_LFSR <<= 1;
state->sh6840_LFSR |= newxor;
@ -248,7 +245,6 @@ static void sh6840_register_state_globals(device_t *device)
state_save_register_device_item_array(device, 0, state->sh6840_volume);
state_save_register_device_item(device, 0, state->sh6840_MSB_latch);
state_save_register_device_item(device, 0, state->sh6840_LSB_latch);
state_save_register_device_item(device, 0, state->sh6840_LFSR_oldxor);
state_save_register_device_item(device, 0, state->sh6840_LFSR);
state_save_register_device_item(device, 0, state->sh6840_LFSR_clocks);
state_save_register_device_item(device, 0, state->sh6840_clock_count);
@ -335,7 +331,7 @@ static STREAM_UPDATE( beezer_stream_update )
if (noisy != 0)
{
noise_clocks_this_sample = sh6840_update_noise(state, t->clocks - chan1_clocks);
if (clocks) state->sh6840_noiselatch3 = state->sh6840_LFSR_oldxor;
if (clocks) state->sh6840_noiselatch3 = (state->sh6840_LFSR&0x1);
}
/* handle timer 2 if enabled */
@ -423,7 +419,6 @@ static DEVICE_RESET( common_sh_reset )
state->sh6840_noiselatch3 = 0;
/* LFSR */
state->sh6840_LFSR_oldxor = 0;
state->sh6840_LFSR = 0xffffffff;
state->sh6840_LFSR_clocks = 0;
}
@ -493,7 +488,7 @@ WRITE8_DEVICE_HANDLER( beezer_timer1_w )
state->sh6840_latchwrite = data&0x80;
if ((!state->sh6840_latchwriteold) && (state->sh6840_latchwrite)) // rising edge
{
state->sh6840_noiselatch1 = state->sh6840_LFSR_oldxor;
state->sh6840_noiselatch1 = (state->sh6840_LFSR&0x1);
}
}
@ -503,7 +498,7 @@ READ8_DEVICE_HANDLER( beezer_noise_r )
/* force an update of the stream */
state->stream->update();
return state->sh6840_LFSR_oldxor;
return (state->sh6840_LFSR&0x1);
}
WRITE8_DEVICE_HANDLER( beezer_sh6840_w )