ref: 2d2ef2908d0008ff66352dc97d7ceb59f715d5bf
parent: 4d87aa4e309381e6c11f0e2d190eec248152a093
author: Olav Sørensen <olav.sorensen@live.no>
date: Sun Jan 24 08:24:06 EST 2021
Some cleanup and changing of comments
--- a/src/ft2_replayer.c
+++ b/src/ft2_replayer.c
@@ -28,7 +28,7 @@
*/
// non-FT2 precalced stuff (these are kinda big...)
-static double dPeriod2HzTab[65536], dLogTab[768], dLogMulTab[32], dHz2MixDeltaMul;
+static double dPeriod2HzTab[65536], dLogTab[768], dExp2MulTab[32], dHz2MixDeltaMul;
static uint32_t revMixDeltaTab[65536];
static bool bxxOverflow;
static tonTyp nilPatternLine[MAX_VOICES];
@@ -274,9 +274,8 @@
const uint16_t invPeriod = (12 * 192 * 4) - (uint16_t)i; // this intentionally 16-bit-underflows to be accurate to FT2
const int32_t octave = invPeriod / 768;
const int32_t period = invPeriod % 768;
- const int32_t invOct = (14 - octave) & 0x1F; // accurate to FT2
- dPeriod2HzTab[i] = dLogTab[period] * dLogMulTab[invOct]; // x = y / 2^invOct
+ dPeriod2HzTab[i] = dLogTab[period] * dExp2MulTab[(14-octave) & 31]; // x = y >> ((14-octave) & 31)
}
}
else
@@ -314,10 +313,10 @@
double getSampleC4Rate(sampleTyp *s)
{int32_t note = (96/2) + s->relTon;
- if (note >= (12*10)-1)
+ if (note >= (10*12)-1)
return -1; // B-9 (from relTon) = illegal! (won't play in replayer)
- const int32_t C4Period = (note * 16) + (((int8_t)s->fine >> 3) + 16);
+ const int32_t C4Period = (note << 4) + (((int8_t)s->fine >> 3) + 16);
const uint16_t period = audio.linearFreqTable ? linearPeriods[C4Period] : amigaPeriods[C4Period];
return dPeriod2Hz(period);
@@ -430,11 +429,11 @@
void calcReplayerLogTab(void)
{- for (uint32_t i = 0; i < 32; i++)
- dLogMulTab[i] = 1.0 / (1UL << i);
+ for (int32_t i = 0; i < 32; i++)
+ dExp2MulTab[i] = 1.0 / exp2(i); // 1/2^i
for (int32_t i = 0; i < 768; i++)
- dLogTab[i] = exp2(i * (1.0 / 768.0)) * (8363.0 * 256.0);
+ dLogTab[i] = 8363.0 * 256.0 * exp2(i * (1.0 / 768.0));
}
void calcReplayerVars(int32_t audioFreq)
@@ -562,7 +561,7 @@
ch->relTonNr = s->relTon;
ton += ch->relTonNr;
- if (ton >= 12*10)
+ if (ton >= 10*12)
return;
ch->oldVol = s->vol;
@@ -598,7 +597,7 @@
}
}
-static void volume(stmTyp *ch, uint8_t param); // actually volume slide
+static void volume(stmTyp *ch, uint8_t param); // volume slide
static void vibrato2(stmTyp *ch);
static void tonePorta(stmTyp *ch, uint8_t param);
@@ -632,8 +631,8 @@
ch->fPortaDownSpeed = param;
ch->realPeriod += param << 2;
- if ((int16_t)ch->realPeriod > 32000-1)
- ch->realPeriod = 32000-1;
+ if ((int16_t)ch->realPeriod > MAX_FRQ-1) // FT2 bug, should've been unsigned comparison
+ ch->realPeriod = MAX_FRQ-1;
ch->outPeriod = ch->realPeriod;
ch->status |= IS_Period;
@@ -1181,8 +1180,8 @@
uint16_t newPeriod = ch->realPeriod;
newPeriod += param;
- if ((int16_t)newPeriod > 32000-1)
- newPeriod = 32000-1;
+ if ((int16_t)newPeriod > MAX_FRQ-1) // FT2 bug, should've been unsigned comparison
+ newPeriod = MAX_FRQ-1;
ch->outPeriod = ch->realPeriod = newPeriod;
ch->status |= IS_Period;
@@ -1696,7 +1695,7 @@
uint16_t tmpPeriod = (autoVibVal * (int16_t)autoVibAmp) >> 16;
tmpPeriod += ch->outPeriod;
- if (tmpPeriod > 32000-1)
+ if (tmpPeriod > MAX_FRQ-1)
tmpPeriod = 0; // yes, FT2 does this (!)
#ifdef HAS_MIDI
@@ -1727,7 +1726,12 @@
int32_t tmpPeriod;
const int32_t fineTune = ((int8_t)ch->fineTune >> 3) + 16;
- int32_t hiPeriod = 1536; // FT2 bug: should've been 1935
+
+ /* FT2 bug, should've been 10*12*16. Notes above B-7 (95) will have issues.
+ ** You can only achieve such high notes by having a high relative note setting.
+ */
+ int32_t hiPeriod = 8*12*16;
+
int32_t loPeriod = 0;
for (int32_t i = 0; i < 8; i++)
@@ -1736,7 +1740,7 @@
int32_t lookUp = tmpPeriod - 8;
if (lookUp < 0)
- lookUp = 0; // 8bitbubsy: safety fix (C-0 w/ finetune <= -65)
+ lookUp = 0; // safety fix (C-0 w/ finetune <= -65). This buggy read seems to return 0 in FT2 (TODO: Verify...)
if (period >= note2Period[lookUp])
hiPeriod = (tmpPeriod - fineTune) & ~15;
@@ -1745,8 +1749,8 @@
}
tmpPeriod = loPeriod + fineTune + (arpNote << 4);
- if (tmpPeriod >= 1550) // FT2 bugs: off-by-one edge case, and should've been 1935 (1936)
- tmpPeriod = 1551;
+ if (tmpPeriod >= (8*12*16+15)-1) // FT2 bug, should've been 10*12*16+16 (also notice the +2 difference)
+ tmpPeriod = (8*12*16+16)-1;
return note2Period[tmpPeriod];
}
@@ -1829,8 +1833,8 @@
ch->portaDownSpeed = param;
ch->realPeriod += param << 2;
- if ((int16_t)ch->realPeriod > 32000-1) // FT2 bug, should've been unsigned comparison
- ch->realPeriod = 32000-1;
+ if ((int16_t)ch->realPeriod > MAX_FRQ-1) // FT2 bug, should've been unsigned comparison
+ ch->realPeriod = MAX_FRQ-1;
ch->outPeriod = ch->realPeriod;
ch->status |= IS_Period;
@@ -1959,7 +1963,7 @@
ch->tremPos += ch->tremSpeed;
}
-static void volume(stmTyp *ch, uint8_t param) // actually volume slide
+static void volume(stmTyp *ch, uint8_t param) // volume slide
{if (param == 0)
param = ch->volSlideSpeed;
--- a/src/ft2_replayer.h
+++ b/src/ft2_replayer.h
@@ -42,7 +42,8 @@
#define MAX_BPM 999
#define MAX_VOICES 32
#define TRACK_WIDTH (5 * MAX_VOICES)
-#define MAX_NOTES ((12 * 10 * 16) + 16)
+#define MAX_FRQ 32000
+#define MAX_NOTES (10*12*16+16)
#define MAX_PATTERNS 256
#define MAX_PATT_LEN 256
#define MAX_INST 128