From 6fd10cdacb5cbe47a4fc339c20a733d4a9a384a1 Mon Sep 17 00:00:00 2001 From: Takamichi Horikawa Date: Sat, 26 Nov 2016 20:57:57 +0900 Subject: initial --- libopna/opnadrum.c | 141 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 libopna/opnadrum.c (limited to 'libopna/opnadrum.c') diff --git a/libopna/opnadrum.c b/libopna/opnadrum.c new file mode 100644 index 0000000..2527c1a --- /dev/null +++ b/libopna/opnadrum.c @@ -0,0 +1,141 @@ +#include "opnadrum.h" + +static const uint16_t steps[49] = { + 16, 17, 19, 21, 23, 25, 28, + 31, 34, 37, 41, 45, 50, 55, + 60, 66, 73, 80, 88, 97, 107, + 118, 130, 143, 157, 173, 190, 209, + 230, 253, 279, 307, 337, 371, 408, + 449, 494, 544, 598, 658, 724, 796, + 876, 963, 1060, 1166, 1282, 1411, 1552 +}; + +static const int8_t step_inc[8] = { + -1, -1, -1, -1, 2, 5, 7, 9 +}; + +void opna_drum_reset(struct opna_drum *drum) { + for (int d = 0; d < 6; d++) { + drum->drums[d].data = 0; + drum->drums[d].playing = false; + drum->drums[d].index = 0; + drum->drums[d].len = 0; + drum->drums[d].level = 0; + drum->drums[d].left = false; + drum->drums[d].right = false; + } + drum->total_level = 0; +} + +void opna_drum_set_rom(struct opna_drum *drum, void *romptr) { + uint8_t *rom = (uint8_t *)romptr; + static const struct { + unsigned start; + unsigned end; + int div; + } part[6] = { + {OPNA_ROM_BD_START, OPNA_ROM_SD_START-1, 3}, + {OPNA_ROM_SD_START, OPNA_ROM_TOP_START-1, 3}, + {OPNA_ROM_TOP_START, OPNA_ROM_HH_START-1, 3}, + {OPNA_ROM_HH_START, OPNA_ROM_TOM_START-1, 3}, + {OPNA_ROM_TOM_START, OPNA_ROM_RIM_START-1, 6}, + {OPNA_ROM_RIM_START, OPNA_ROM_SIZE-1, 6}, + }; + drum->drums[0].data = drum->rom_bd; + drum->drums[1].data = drum->rom_sd; + drum->drums[2].data = drum->rom_top; + drum->drums[3].data = drum->rom_hh; + drum->drums[4].data = drum->rom_tom; + drum->drums[5].data = drum->rom_rim; + for (int p = 0; p < 6; p++) { + drum->drums[p].playing = false; + drum->drums[p].index = 0; + unsigned addr = part[p].start << 1; + int step = 0; + unsigned acc = 0; + int outindex = 0; + for (;;) { + if ((addr>>1) == part[p].end) break; + unsigned data = rom[addr>>1]; + if (!(addr&1)) data >>= 4; + data &= ((1<<4)-1); + int acc_diff = ((((data&7)<<1)|1) * steps[step]) >> 3; + if (data&8) acc_diff = -acc_diff; + acc += acc_diff; + step += step_inc[data&7]; + if (step < 0) step = 0; + if (step > 48) step = 48; + addr++; + + int out = acc & ((1u<<12)-1); + if (out >= (1<<11)) out -= (1<<12); + int16_t out16 = out << 4; + for (int i = 0; i < part[p].div; i++) { + drum->drums[p].data[outindex] = out16; + outindex++; + } + } + drum->drums[p].len = outindex; + } +} + +void opna_drum_mix(struct opna_drum *drum, int16_t *buf, int samples) { + for (int i = 0; i < samples; i++) { + int32_t lo = buf[i*2+0]; + int32_t ro = buf[i*2+1]; + for (int d = 0; d < 6; d++) { + if (drum->drums[d].playing && drum->drums[d].data) { + int co = drum->drums[d].data[drum->drums[d].index]; + co >>= 4; + unsigned level = (drum->drums[d].level^0x1f) + (drum->total_level^0x3f); + co *= 15 - (level&7); + co >>= 1+(level>>3); + if (drum->drums[d].left) lo += co; + if (drum->drums[d].right) ro += co; + drum->drums[d].index++; + if (drum->drums[d].index == drum->drums[d].len) { + drum->drums[d].index = 0; + drum->drums[d].playing = false; + } + } + } + if (lo < INT16_MIN) lo = INT16_MIN; + if (lo > INT16_MAX) lo = INT16_MAX; + if (ro < INT16_MIN) ro = INT16_MIN; + if (ro > INT16_MAX) ro = INT16_MAX; + buf[i*2+0] = lo; + buf[i*2+1] = ro; + } +} + +void opna_drum_writereg(struct opna_drum *drum, unsigned reg, unsigned val) { + val &= 0xff; + switch (reg) { + case 0x10: + for (int d = 0; d < 6; d++) { + if (val & (1<drums[d].playing = !(val & 0x80); + drum->drums[d].index = 0; + } + } + break; + case 0x11: + drum->total_level = val & 0x3f; + break; + case 0x18: + case 0x19: + case 0x1a: + case 0x1b: + case 0x1c: + case 0x1d: + { + int d = reg - 0x18; + drum->drums[d].left = val & 0x80; + drum->drums[d].right = val & 0x40; + drum->drums[d].level = val & 0x1f; + } + break; + default: + break; + } +} -- cgit v1.2.3