diff options
Diffstat (limited to 'source/dsp1emu.c')
| -rw-r--r-- | source/dsp1emu.c | 41 |
1 files changed, 39 insertions, 2 deletions
diff --git a/source/dsp1emu.c b/source/dsp1emu.c index 76df362..d83e078 100644 --- a/source/dsp1emu.c +++ b/source/dsp1emu.c @@ -187,11 +187,19 @@ void DSP1_Inverse(int16_t Coefficient, int16_t Exponent, int16_t* iCoefficient, } /* Step Three: Normalize */ +#ifdef __GNUC__ + { + const int shift = __builtin_clz(Coefficient) - (8 * sizeof(int) - 15); + Coefficient <<= shift; + Exponent -= shift; + } +#else while (Coefficient < 0x4000) { Coefficient <<= 1; Exponent--; } +#endif /* Step Four: Special Case */ if (Coefficient == 0x4000) @@ -336,9 +344,18 @@ int16_t DSP1_Cos(int16_t Angle) void DSP1_Normalize(int16_t m, int16_t* Coefficient, int16_t* Exponent) { - int16_t i = 0x4000; int16_t e = 0; +#ifdef __GNUC__ + int16_t n = m < 0 ? ~m : m; + + if (n == 0) + e = 15; + else + e = __builtin_clz(n) - (8 * sizeof(int) - 15); +#else + int16_t i = 0x4000; + if (m < 0) { while ((m & i) && i) @@ -355,6 +372,7 @@ void DSP1_Normalize(int16_t m, int16_t* Coefficient, int16_t* Exponent) e++; } } +#endif if (e > 0) *Coefficient = m * DSP1ROM[0x21 + e] << 1; @@ -368,9 +386,18 @@ void DSP1_NormalizeDouble(int32_t Product, int16_t* Coefficient, int16_t* Expone { int16_t n = Product & 0x7fff; int16_t m = Product >> 15; - int16_t i = 0x4000; int16_t e = 0; +#ifdef __GNUC__ + int16_t t = m < 0 ? ~m : m; + + if (t == 0) + e = 15; + else + e = __builtin_clz(t) - (8 * sizeof(int) - 15); +#else + int16_t i = 0x4000; + if (m < 0) { while ((m & i) && i) @@ -387,6 +414,7 @@ void DSP1_NormalizeDouble(int32_t Product, int16_t* Coefficient, int16_t* Expone e++; } } +#endif if (e > 0) { @@ -396,6 +424,14 @@ void DSP1_NormalizeDouble(int32_t Product, int16_t* Coefficient, int16_t* Expone *Coefficient += n * DSP1ROM[0x0040 - e] >> 15; else { +#ifdef __GNUC__ + t = m < 0 ? ~(n | 0x8000) : n; + + if (t == 0) + e += 15; + else + e += __builtin_clz(t) - (8 * sizeof(int) - 15); +#else i = 0x4000; if (m < 0) @@ -414,6 +450,7 @@ void DSP1_NormalizeDouble(int32_t Product, int16_t* Coefficient, int16_t* Expone e++; } } +#endif if (e > 15) *Coefficient = n * DSP1ROM[0x0012 + e] << 1; |