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author 0kmg <9137159+0kmg@users.noreply.github.com>2022-02-03 05:57:36 -0900
committer GitHub <noreply@github.com>2022-02-03 09:57:36 -0500
commit0bedd480184d34b7b90b17a1ac5e55b7277f9730 (patch)
tree8c11187a3b6f49b0317d5afdbf537c2a456cc757 /src/devices/sound
parent6c84aa716080b0eeea61bcad4388505b04d39370 (diff)
nes_apu.cpp: Added noise channel period table for PAL systems. (#9256)
- Fixed a value in the parallel NTSC table for the largest period (lowest freq). - Fixed a value in the counter length table (for all channels but DMC).
Diffstat (limited to 'src/devices/sound')
-rw-r--r--src/devices/sound/nes_apu.cpp33
-rw-r--r--src/devices/sound/nes_defs.h12
2 files changed, 17 insertions, 28 deletions
diff --git a/src/devices/sound/nes_apu.cpp b/src/devices/sound/nes_apu.cpp
index 2fdc5a54999..8c61315581d 100644
--- a/src/devices/sound/nes_apu.cpp
+++ b/src/devices/sound/nes_apu.cpp
@@ -49,36 +49,23 @@
#include "emu.h"
#include "nes_apu.h"
-/* INTERNAL FUNCTIONS */
+// INTERNAL FUNCTIONS
-/* INITIALIZE WAVE TIMES RELATIVE TO SAMPLE RATE */
-static void create_vbltimes(u32 * table,const u8 *vbl,unsigned int rate)
+// INITIALIZE WAVE TIMES RELATIVE TO SAMPLE RATE
+static void create_vbltimes(u32 *table, const u8 *vbl, unsigned int rate)
{
- int i;
-
- for (i = 0; i < 0x20; i++)
+ for (int i = 0; i < 0x20; i++)
table[i] = vbl[i] * rate;
}
-/* INITIALIZE SAMPLE TIMES IN TERMS OF VSYNCS */
+// INITIALIZE SAMPLE TIMES IN TERMS OF VSYNCS
void nesapu_device::create_syncs(unsigned long sps)
{
- int i;
- unsigned long val = sps;
-
- for (i = 0; i < SYNCS_MAX1; i++)
- {
- m_sync_times1[i] = val;
- val += sps;
- }
+ for (int i = 0; i < SYNCS_MAX1; i++)
+ m_sync_times1[i] = sps * (i + 1);
- val = 0;
- for (i = 0; i < SYNCS_MAX2; i++)
- {
- m_sync_times2[i] = val;
- m_sync_times2[i] >>= 2;
- val += sps;
- }
+ for (int i = 0; i < SYNCS_MAX2; i++)
+ m_sync_times2[i] = (sps * i) >> 2;
}
DEFINE_DEVICE_TYPE(NES_APU, nesapu_device, "nesapu", "N2A03 APU")
@@ -387,7 +374,7 @@ s8 nesapu_device::apu_noise(apu_t::noise_t *chan)
if (0 == chan->vbl_length)
return 0;
- freq = noise_freq[chan->regs[2] & 0x0F];
+ freq = noise_freq[m_is_pal][chan->regs[2] & 0x0F];
chan->phaseacc -= 4;
while (chan->phaseacc < 0)
{
diff --git a/src/devices/sound/nes_defs.h b/src/devices/sound/nes_defs.h
index bd0c3401a35..0a32a148de6 100644
--- a/src/devices/sound/nes_defs.h
+++ b/src/devices/sound/nes_defs.h
@@ -195,7 +195,7 @@ struct apu_t
/* vblank length table used for squares, triangle, noise */
static const apu_t::uint8 vbl_length[32] =
{
- 5, 127, 10, 1, 19, 2, 40, 3, 80, 4, 30, 5, 7, 6, 13, 7,
+ 5, 127, 10, 1, 20, 2, 40, 3, 80, 4, 30, 5, 7, 6, 13, 7,
6, 8, 12, 9, 24, 10, 48, 11, 96, 12, 36, 13, 8, 14, 16, 15
};
@@ -205,10 +205,12 @@ static const int freq_limit[8] =
0x3FF, 0x555, 0x666, 0x71C, 0x787, 0x7C1, 0x7E0, 0x7F0,
};
-/* table of noise frequencies */
-static const int noise_freq[16] =
+// table of noise period
+// each fundamental is determined as: freq = master / period / 93
+static const int noise_freq[2][16] =
{
- 4, 8, 16, 32, 64, 96, 128, 160, 202, 254, 380, 508, 762, 1016, 2034, 2046
+ { 4, 8, 16, 32, 64, 96, 128, 160, 202, 254, 380, 508, 762, 1016, 2034, 4068 }, // NTSC
+ { 4, 8, 14, 30, 60, 88, 118, 148, 188, 236, 354, 472, 708, 944, 1890, 3778 } // PAL
};
// dpcm (cpu) cycle period
@@ -216,7 +218,7 @@ static const int noise_freq[16] =
static const int dpcm_clocks[2][16] =
{
{ 428, 380, 340, 320, 286, 254, 226, 214, 190, 160, 142, 128, 106, 85, 72, 54 }, // NTSC
- { 398, 354, 316, 298, 276, 236, 210, 198, 176, 148, 132, 118, 98, 78, 66, 50 } // PAL
+ { 398, 354, 316, 298, 276, 236, 210, 198, 176, 148, 132, 118, 98, 78, 66, 50 } // PAL
};
/* ratios of pos/neg pulse for square waves */