From ce7d0133b95729e76efa823169ddaa4a46a7b1e8 Mon Sep 17 00:00:00 2001
From: Holger Wirtz <wirtz@parasitstudio.de>
Date: Wed, 23 May 2018 15:45:56 +0200
Subject: [PATCH] Small FPU optimisations.

---
 EngineMkI.cpp |  4 ++--
 dx7note.cpp   | 10 ++++++----
 sin.cpp       |  4 ++--
 synth.h       |  4 ++++
 4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/EngineMkI.cpp b/EngineMkI.cpp
index 2a88c7f..efe9254 100644
--- a/EngineMkI.cpp
+++ b/EngineMkI.cpp
@@ -38,7 +38,7 @@
 #if _MSC_VER < 1800
     FRAC_NUM log2(FRAC_NUM n)  {  
         //return log(n) / log(2.0);  
-        return logf(n) / logf(2.0);  
+        return LOG_FUNC(n) / LOG_FUNC(2.0);  
     }
     FRAC_NUM round(FRAC_NUM n) {
         return n < 0.0 ? ceil(n - 0.5) : floor(n + 0.5);
@@ -83,7 +83,7 @@ EngineMkI::EngineMkI() {
     
     for(int i=0;i<SINLOG_TABLESIZE;i++) {
         //float x1 = sin(((0.5+i)/bitReso) * M_PI/2.0);
-        float x1 = sinf(((0.5+i)/bitReso) * M_PI/2.0);
+        float x1 = SIN_FUNC(((0.5+i)/bitReso) * M_PI/2.0);
         sinLogTable[i] = round(-1024 * log2(x1));
     }
     
diff --git a/dx7note.cpp b/dx7note.cpp
index fa04a24..49d6114 100644
--- a/dx7note.cpp
+++ b/dx7note.cpp
@@ -27,7 +27,7 @@ const int FEEDBACK_BITDEPTH = 8;
 
 int32_t midinote_to_logfreq(int midinote) {
   //const int32_t base = 50857777;  // (1 << 24) * (log(440) / log(2) - 69/12)
-  const int32_t base = 50857777;  // (1 << 24) * (logf(440) / logf(2) - 69/12)
+  const int32_t base = 50857777;  // (1 << 24) * (LOG_FUNC(440) / LOG_FUNC(2) - 69/12)
   const int32_t step = (1 << 24) / 12;
   return base + step * midinote;
 }
@@ -46,14 +46,15 @@ int32_t osc_freq(int midinote, int mode, int coarse, int fine, int detune) {
   if (mode == 0) {
     logfreq = midinote_to_logfreq(midinote);
     // could use more precision, closer enough for now. those numbers comes from my DX7
-    FRAC_NUM detuneRatio = 0.0209 * exp(-0.396 * (((float)logfreq) / (1 << 24))) / 7;
+    //FRAC_NUM detuneRatio = 0.0209 * exp(-0.396 * (((float)logfreq) / (1 << 24))) / 7;
+    FRAC_NUM detuneRatio = 0.0209 * EXP_FUNC(-0.396 * (((float)logfreq) / (1 << 24))) / 7;
     logfreq += detuneRatio * logfreq * (detune - 7);
 
     logfreq += coarsemul[coarse & 31];
     if (fine) {
       // (1 << 24) / log(2)
       //logfreq += (int32_t)floor(24204406.323123 * log(1 + 0.01 * fine) + 0.5);
-      logfreq += (int32_t)floor(24204406.323123 * logf(1 + 0.01 * fine) + 0.5);
+      logfreq += (int32_t)floor(24204406.323123 * LOG_FUNC(1 + 0.01 * fine) + 0.5);
     }
 
     // // This was measured at 7.213Hz per count at 9600Hz, but the exact
@@ -245,7 +246,8 @@ void Dx7Note::compute(int32_t *buf, int32_t lfo_val, int32_t lfo_delay, const Co
         uint32_t sensamp = (uint32_t)(((uint64_t) amd_mod) * ((uint64_t) ampmodsens_[op]) >> 24);
 
         // TODO: mehhh.. this needs some real tuning.
-        uint32_t pt = exp(((float)sensamp) / 262144 * 0.07 + 12.2);
+        //uint32_t pt = exp(((float)sensamp) / 262144 * 0.07 + 12.2);
+        uint32_t pt = EXP_FUNC(((float)sensamp) / 262144 * 0.07 + 12.2);
         uint32_t ldiff = (uint32_t)(((uint64_t)level) * (((uint64_t)pt << 4)) >> 28);
         level -= ldiff;
       }
diff --git a/sin.cpp b/sin.cpp
index 955c3bb..1949cd5 100644
--- a/sin.cpp
+++ b/sin.cpp
@@ -31,9 +31,9 @@ int32_t sintab[SIN_N_SAMPLES + 1];
 void Sin::init() {
   FRAC_NUM dphase = 2 * M_PI / SIN_N_SAMPLES;
   //int32_t c = (int32_t)floor(cos(dphase) * (1 << 30) + 0.5);
-  int32_t c = (int32_t)floor(cosf(dphase) * (1 << 30) + 0.5);
+  int32_t c = (int32_t)floor(COS_FUNC(dphase) * (1 << 30) + 0.5);
   //int32_t s = (int32_t)floor(sin(dphase) * (1 << 30) + 0.5);
-  int32_t s = (int32_t)floor(sinf(dphase) * (1 << 30) + 0.5);
+  int32_t s = (int32_t)floor(SIN_FUNC(dphase) * (1 << 30) + 0.5);
   int32_t u = 1 << 30;
   int32_t v = 0;
   for (int i = 0; i < SIN_N_SAMPLES / 2; i++) {
diff --git a/synth.h b/synth.h
index 6080590..dc07e3b 100644
--- a/synth.h
+++ b/synth.h
@@ -63,5 +63,9 @@ inline static T max(const T& a, const T& b) {
 #define QER(n,b) ( ((float)n)/(1<<b) )
 
 #define FRAC_NUM float
+#define SIN_FUNC sinf
+#define COS_FUNC cosf
+#define LOG_FUNC logf
+#define EXP_FUNC expf
 
 #endif  // __SYNTH_H