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https://github.com/holub/mame
synced 2025-05-18 19:49:35 +03:00
minor cleanup/precompute rates
This commit is contained in:
Michaël Banaan Ananas
parent
ff2de72d6a
commit
03ada8a386
@ -52,8 +52,8 @@
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instruments in hotdebut).
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Thanks to Team Japump! for MP3s from a real PCB.
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fixed crash if MAME is run with no sound.
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June 4, 2003 - Changed to dual-license with LGPL for use in OpenMSX.
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OpenMSX contributed a bugfix where looped samples were
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June 4, 2003 - Changed to dual-license with LGPL for use in openMSX.
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openMSX contributed a bugfix where looped samples were
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not being addressed properly, causing pitch fluctuation.
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With further improvements over the years by MAME team.
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@ -108,14 +108,15 @@ typedef struct
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UINT32 env_vol_step;
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UINT32 env_vol_lim;
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INT8 env_preverb;
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int num; /* slot number (for debug only) */
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struct _YMF278BChip *chip; /* pointer back to parent chip */
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} YMF278BSlot;
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typedef struct
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typedef struct _YMF278BChip
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{
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UINT8 pcmregs[256];
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YMF278BSlot slots[24];
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INT8 lsitest0;
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INT8 lsitest1;
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INT8 wavetblhdr;
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INT8 memmode;
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INT32 memadr;
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@ -142,6 +143,9 @@ typedef struct
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UINT32 romsize;
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int clock;
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// precomputed tables
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UINT32 lut_ar[64]; // attack rate
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UINT32 lut_dr[64]; // decay rate
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INT32 volume[256*4]; // precalculated attenuation values with some margin for envelope and pan levels
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int pan_left[16],pan_right[16]; // pan volume offsets
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INT32 mix_level[8];
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@ -172,6 +176,8 @@ INLINE UINT8 ymf278b_read_memory(YMF278BChip *chip, UINT32 offset)
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}
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/**************************************************************************/
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static int ymf278b_compute_rate(YMF278BSlot *slot, int val)
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{
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int res, oct;
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@ -198,36 +204,6 @@ static int ymf278b_compute_rate(YMF278BSlot *slot, int val)
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return res;
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}
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INLINE UINT32 ymf278_compute_attack_rate(int num)
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{
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// estimated (less accurate on high rates)
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UINT32 samples;
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if (num <= 3 || num == 63)
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samples = 0;
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else if (num >= 60)
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samples = 17;
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else
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samples = (67 << (15 - num / 4)) / (4 + num % 4);
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return samples;
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}
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static UINT32 ymf278_compute_decay_rate(int num)
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{
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// estimated
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UINT32 samples;
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if (num <= 3)
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samples = 0;
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else if (num >= 60)
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samples = 15 << 4;
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else
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samples = (15 << (21 - num / 4)) / (4 + num % 4);
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return samples;
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}
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static UINT32 ymf278_compute_decay_env_vol_step(YMF278BSlot *slot, int val)
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{
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int rate;
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@ -248,7 +224,7 @@ static UINT32 ymf278_compute_decay_env_vol_step(YMF278BSlot *slot, int val)
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if (rate < 4)
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res = 0;
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else
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res = (256U<<23) / ymf278_compute_decay_rate(rate);
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res = (256U<<23) / slot->chip->lut_dr[rate];
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return res;
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}
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@ -293,8 +269,8 @@ static void ymf278b_compute_envelope(YMF278BSlot *slot)
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else
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{
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// NOTE: attack rate is linear here, but datasheet shows a smooth curve
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LOG(("YMF278B: Attack, val = %d, rate = %d, delay = %g\n", slot->AR, rate, ymf278_compute_attack_rate(rate)*1000.0));
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slot->env_vol_step = ~((256U<<23) / ymf278_compute_attack_rate(rate));
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LOG(("YMF278B: Attack, val = %d, rate = %d, delay = %g\n", slot->AR, rate, slot->chip->lut_ar[rate]*1000.0));
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slot->env_vol_step = ~((256U<<23) / slot->chip->lut_ar[rate]);
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}
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break;
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@ -304,7 +280,7 @@ static void ymf278b_compute_envelope(YMF278BSlot *slot)
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case 1:
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if(slot->DL)
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{
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LOG(("YMF278B: Decay step 1, dl=%d, val = %d rate = %d, delay = %g, PRVB = %d, DAMP = %d\n", slot->DL, slot->D1R, ymf278b_compute_rate(slot, slot->D1R), ymf278_compute_decay_rate(ymf278b_compute_rate(slot, slot->D1R))*1000.0, slot->preverb, slot->DAMP));
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LOG(("YMF278B: Decay step 1, dl=%d, val = %d rate = %d, delay = %g, PRVB = %d, DAMP = %d\n", slot->DL, slot->D1R, ymf278b_compute_rate(slot, slot->D1R), slot->chip->lut_dr[ymf278b_compute_rate(slot, slot->D1R)]*1000.0, slot->preverb, slot->DAMP));
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slot->env_vol_step = ymf278_compute_decay_env_vol_step(slot, slot->D1R);
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slot->env_vol_lim = (slot->DL*8)<<23;
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}
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@ -319,7 +295,7 @@ static void ymf278b_compute_envelope(YMF278BSlot *slot)
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// Decay 2
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case 2:
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LOG(("YMF278B: Decay step 2, val = %d, rate = %d, delay = %g, , PRVB = %d, DAMP = %d, current vol = %d\n", slot->D2R, ymf278b_compute_rate(slot, slot->D2R), ymf278_compute_decay_rate(ymf278b_compute_rate(slot, slot->D2R))*1000.0, slot->preverb, slot->DAMP, slot->env_vol >> 23));
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LOG(("YMF278B: Decay step 2, val = %d, rate = %d, delay = %g, , PRVB = %d, DAMP = %d, current vol = %d\n", slot->D2R, ymf278b_compute_rate(slot, slot->D2R), slot->chip->lut_dr[ymf278b_compute_rate(slot, slot->D2R)]*1000.0, slot->preverb, slot->DAMP, slot->env_vol >> 23));
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slot->env_vol_step = ymf278_compute_decay_env_vol_step(slot, slot->D2R);
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slot->env_vol_lim = 256U<<23;
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break;
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@ -335,7 +311,7 @@ static void ymf278b_compute_envelope(YMF278BSlot *slot)
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// Release
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case 4:
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LOG(("YMF278B: Release, val = %d, rate = %d, delay = %g, PRVB = %d, DAMP = %d\n", slot->RR, ymf278b_compute_rate(slot, slot->RR), ymf278_compute_decay_rate(ymf278b_compute_rate(slot, slot->RR))*1000.0, slot->preverb, slot->DAMP));
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LOG(("YMF278B: Release, val = %d, rate = %d, delay = %g, PRVB = %d, DAMP = %d\n", slot->RR, ymf278b_compute_rate(slot, slot->RR), slot->chip->lut_dr[ymf278b_compute_rate(slot, slot->RR)]*1000.0, slot->preverb, slot->DAMP));
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slot->env_vol_step = ymf278_compute_decay_env_vol_step(slot, slot->RR);
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slot->env_vol_lim = 256U<<23;
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break;
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@ -468,6 +444,9 @@ static TIMER_CALLBACK( ymf278b_timer_b_tick )
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}
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}
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/**************************************************************************/
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static void ymf278b_A_w(running_machine &machine, YMF278BChip *chip, UINT8 reg, UINT8 data)
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{
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// FM register array 0 (compatible with YMF262)
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@ -902,6 +881,8 @@ READ8_DEVICE_HANDLER( ymf278b_r )
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}
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/**************************************************************************/
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static DEVICE_RESET( ymf278b )
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{
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YMF278BChip *chip = get_safe_token(device);
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@ -954,6 +935,8 @@ static DEVICE_RESET( ymf278b )
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static void ymf278b_init(device_t *device, YMF278BChip *chip, void (*cb)(device_t *, int))
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{
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int i;
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chip->rom = *device->region();
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chip->romsize = device->region()->bytes();
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chip->clock = device->clock();
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@ -964,6 +947,39 @@ static void ymf278b_init(device_t *device, YMF278BChip *chip, void (*cb)(device_
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chip->timer_b = device->machine().scheduler().timer_alloc(FUNC(ymf278b_timer_b_tick), chip);
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chip->timer_busy = device->machine().scheduler().timer_alloc(FUNC(ymf278b_timer_busy_clear), chip);
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chip->timer_ld = device->machine().scheduler().timer_alloc(FUNC(ymf278b_timer_ld_clear), chip);
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for (i = 0; i < 24; i++)
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{
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chip->slots[i].num = i;
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chip->slots[i].chip = chip;
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}
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}
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static void precompute_rate_tables(YMF278BChip *chip)
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{
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int i;
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// decay rate
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for (i = 0; i < 64; i++)
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{
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if (i <= 3)
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chip->lut_dr[i] = 0;
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else if (i >= 60)
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chip->lut_dr[i] = 15 << 4;
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else
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chip->lut_dr[i] = (15 << (21 - i / 4)) / (4 + i % 4);
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}
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// attack rate (manual shows curve instead of linear though, so this is not entirely accurate)
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for (i = 0; i < 64; i++)
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{
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if (i <= 3 || i == 63)
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chip->lut_ar[i] = 0;
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else if (i >= 60)
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chip->lut_ar[i] = 17;
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else
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chip->lut_ar[i] = (67 << (15 - i / 4)) / (4 + i % 4);
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}
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}
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static void ymf278b_register_save_state(device_t *device, YMF278BChip *chip)
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@ -971,8 +987,6 @@ static void ymf278b_register_save_state(device_t *device, YMF278BChip *chip)
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int i;
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device->save_item(NAME(chip->pcmregs));
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device->save_item(NAME(chip->lsitest0));
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device->save_item(NAME(chip->lsitest1));
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device->save_item(NAME(chip->wavetblhdr));
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device->save_item(NAME(chip->memmode));
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device->save_item(NAME(chip->memadr));
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@ -1045,6 +1059,9 @@ static DEVICE_START( ymf278b )
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ymf278b_init(device, chip, intf->irq_callback);
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chip->stream = device->machine().sound().stream_alloc(*device, 0, 2, device->clock()/768, chip, ymf278b_pcm_update);
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// rate tables
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precompute_rate_tables(chip);
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// Volume table, 1 = -0.375dB, 8 = -3dB, 256 = -96dB
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for(i = 0; i < 256; i++)
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chip->volume[i] = 65536*pow(2.0, (-0.375/6)*i);
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