diff options
| -rw-r--r-- | ym2612.c | 76 | ||||
| -rw-r--r-- | ym2612.h | 3 |
2 files changed, 74 insertions, 5 deletions
@@ -254,7 +254,14 @@ void ym_free(ym2612_context *context) #define CSM_MODE 0x80 -static void keyon(ym_operator *op, ym_channel *channel) +#define SSG_ENABLE 8 +#define SSG_INVERT 4 +#define SSG_ALTERNATE 2 +#define SSG_HOLD 1 + +#define SSG_CENTER 0x800 + +static void start_envelope(ym_operator *op, ym_channel *channel) { //Deal with "infinite" attack rates uint8_t rate = op->rates[PHASE_ATTACK]; @@ -268,11 +275,27 @@ static void keyon(ym_operator *op, ym_channel *channel) } else { op->env_phase = PHASE_ATTACK; } +} + +static void keyon(ym_operator *op, ym_channel *channel) +{ + start_envelope(op, channel); op->phase_counter = 0; + op->inverted = op->ssg & SSG_INVERT; } static const uint8_t keyon_bits[] = {0x10, 0x40, 0x20, 0x80}; +static void keyoff(ym_operator *op) +{ + op->env_phase = PHASE_RELEASE; + if (op->inverted) { + //Nemesis says the inversion state doesn't change here, but I don't see how that is observable either way + op->inverted = 0; + op->envelope = (SSG_CENTER - op->envelope) & MAX_ENVELOPE; + } +} + static void csm_keyoff(ym2612_context *context) { context->csm_keyon = 0; @@ -280,7 +303,7 @@ static void csm_keyoff(ym2612_context *context) for (uint8_t op = 2*4, bit = 0; op < 3*4; op++, bit++) { if (changes & keyon_bits[bit]) { - context->operators[op].env_phase = PHASE_RELEASE; + keyoff(context->operators + op); } } } @@ -389,10 +412,20 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) dfprintf(debug_file, "Changing op %d envelope %d by %d in %s phase\n", op, operator->envelope, envelope_inc, operator->env_phase == PHASE_SUSTAIN ? "sustain" : (operator->env_phase == PHASE_DECAY ? "decay": "release")); } + if (operator->ssg) { + if (operator->envelope < SSG_CENTER) { + envelope_inc *= 4; + } else { + envelope_inc = 0; + } + } //envelope value is 10-bits, but it will be used as a 4.8 value operator->envelope += envelope_inc << 2; //clamp to max attenuation value - if (operator->envelope > MAX_ENVELOPE) { + if ( + operator->envelope > MAX_ENVELOPE + || (operator->env_phase == PHASE_RELEASE && operator->envelope >= SSG_CENTER) + ) { operator->envelope = MAX_ENVELOPE; } } @@ -468,7 +501,31 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) } break; } - uint16_t env = operator->envelope + operator->total_level; + uint16_t env = operator->envelope; + if (operator->ssg) { + if (env >= SSG_CENTER) { + if (operator->ssg & SSG_ALTERNATE) { + if (operator->env_phase != PHASE_RELEASE && ( + !(operator->ssg & SSG_HOLD) || ((operator->ssg ^ operator->inverted) & SSG_INVERT) == 0 + )) { + operator->inverted ^= SSG_INVERT; + } + } else if (!(operator->ssg & SSG_HOLD)) { + phase = operator->phase_counter = 0; + } + if ( + (operator->env_phase == PHASE_DECAY || operator->env_phase == PHASE_SUSTAIN) + && !(operator->ssg & SSG_HOLD) + ) { + start_envelope(operator, chan); + env = operator->envelope; + } + } + if (operator->inverted) { + env = (SSG_CENTER - env) & MAX_ENVELOPE; + } + } + env += operator->total_level; if (operator->am) { uint16_t base_am = (context->lfo_am_step & 0x80 ? context->lfo_am_step : ~context->lfo_am_step) & 0x7E; if (ams_shift[chan->ams] >= 0) { @@ -787,7 +844,7 @@ void ym_data_write(ym2612_context * context, uint8_t value) keyon(context->operators + op, context->channels + channel); } else { //printf("Key Off for operator %d in channel %d\n", op, channel); - context->operators[op].env_phase = PHASE_RELEASE; + keyoff(context->operators + op); } } } @@ -841,6 +898,15 @@ void ym_data_write(ym2612_context * context, uint8_t value) operator->sustain_level = MAX_ENVELOPE; } break; + case REG_SSG_EG: + if (!(value & SSG_ENABLE)) { + value = 0; + } + if ((value ^ operator->ssg) & SSG_INVERT) { + operator->inverted ^= SSG_INVERT; + } + operator->ssg = value; + break; } } } else { @@ -27,6 +27,8 @@ typedef struct { uint8_t detune; uint8_t am; uint8_t env_phase; + uint8_t ssg; + uint8_t inverted; } ym_operator; typedef struct { @@ -118,6 +120,7 @@ enum { REG_DECAY_AM = 0x60, REG_SUSTAIN_RATE = 0x70, REG_S_LVL_R_RATE = 0x80, + REG_SSG_EG = 0x90, REG_FNUM_LOW = 0xA0, REG_BLOCK_FNUM_H = 0xA4, |