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| author | Xavi Del Campo <xavi.dcr@tutanota.com> | 2020-01-31 10:32:23 +0100 |
|---|---|---|
| committer | Xavi Del Campo <xavi.dcr@tutanota.com> | 2020-01-31 10:32:23 +0100 |
| commit | 7c24e9a9b02b04dcaf9507acb94091ea70a2c02d (patch) | |
| tree | c28d0748652ad4b4222309e46e6cfc82c0906220 /libfixmath/fix16_exp.c | |
| parent | a2b7b6bb1cc2f4a3258b7b2dbc92399d151f864d (diff) | |
| download | psxsdk-7c24e9a9b02b04dcaf9507acb94091ea70a2c02d.tar.gz | |
Imported pristine psxsdk-20190410 from official repo
Diffstat (limited to 'libfixmath/fix16_exp.c')
| -rwxr-xr-x | libfixmath/fix16_exp.c | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/libfixmath/fix16_exp.c b/libfixmath/fix16_exp.c new file mode 100755 index 0000000..e7e92e4 --- /dev/null +++ b/libfixmath/fix16_exp.c @@ -0,0 +1,48 @@ +#include "fix16.h"
+#include "int64.h"
+
+
+
+#ifndef FIXMATH_NO_CACHE
+static fix16_t _fix16_exp_cache_index[4096] = { 0 };
+static fix16_t _fix16_exp_cache_value[4096] = { 0 };
+#endif
+
+
+
+fix16_t fix16_exp(fix16_t inValue) {
+ if(inValue == 0)
+ return fix16_one;
+ if(inValue == fix16_one)
+ return fix16_e;
+ if(inValue > 681391)
+ return fix16_max;
+ if(inValue < -726817)
+ return 0;
+
+ #ifndef FIXMATH_NO_CACHE
+ fix16_t tempIndex = (inValue ^ (inValue >> 16));
+ tempIndex = (inValue ^ (inValue >> 4)) & 0x0FFF;
+ if(_fix16_exp_cache_index[tempIndex] == inValue)
+ return _fix16_exp_cache_value[tempIndex];
+ #endif
+
+ int64_t tempOut = int64_add(int64_from_int32(fix16_one), int64_from_int32(inValue));
+ int64_t tempValue = int64_from_int32(inValue);
+ uint32_t i, n;
+ for(i = 3, n = 2; i < 13; n *= i, i++) {
+ tempValue = int64_mul_i64_i32(tempValue, inValue);
+ #ifndef FIXMATH_NO_ROUNDING
+ tempValue = int64_add(tempValue, int64_from_int32(fix16_one >> 1));
+ #endif
+ tempValue = int64_shift(tempValue, -16);
+ tempOut = int64_add(tempOut, int64_div_i64_i32(tempValue, n));
+ }
+
+ #ifndef FIXMATH_NO_CACHE
+ _fix16_exp_cache_index[tempIndex] = inValue;
+ _fix16_exp_cache_value[tempIndex] = int64_lo(tempOut);
+ #endif
+
+ return int64_lo(tempOut);
+}
|