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| /* PROLOG END TAG zYx */ |
| |
| #ifdef __SPU__ |
| #ifndef _LOG1PF4_H_ |
| #define _LOG1PF4_H_ 1 |
| |
| #include <spu_intrinsics.h> |
| #include "simdmath.h" |
| |
| #include "logf4.h" |
| #include "divf4.h" |
| |
| /* |
| * FUNCTION |
| * vector float _log1pf4(vector float x) |
| * |
| * DESCRIPTION |
| * The function _log1pf4 computes the natural logarithm of x + 1 |
| * for each of the float word elements of x. |
| * |
| * |
| */ |
| |
| #define LOG1PF4_P0 0.0000000000000000000000000e+00f |
| #define LOG1PF4_P1 1.0000000000000000000000000e+00f |
| #define LOG1PF4_P2 1.4220868022897381610647471e+00f |
| #define LOG1PF4_P3 5.4254553902256308361984338e-01f |
| #define LOG1PF4_P4 4.5971908823142115796400731e-02f |
| |
| #define LOG1PF4_Q0 1.0000000000000000000000000e+00f |
| #define LOG1PF4_Q1 1.9220868007537357247116461e+00f |
| #define LOG1PF4_Q2 1.1702556461286610645089468e+00f |
| #define LOG1PF4_Q3 2.4040413392943396631018516e-01f |
| #define LOG1PF4_Q4 1.0637426466449625625521058e-02f |
| |
| |
| static __inline vector float _log1pf4(vector float x) |
| { |
| vector float onef = spu_splats(1.0f); |
| vector float range = spu_splats(0.35f); |
| vector unsigned int use_log; |
| vector float pr, qr; |
| vector float eresult; |
| vector float rresult; |
| vector float result; |
| |
| use_log = spu_cmpabsgt(x, range); |
| |
| /* |
| * Calculate directly using log(x+1) |
| */ |
| eresult = _logf4(spu_add(x, onef)); |
| |
| /* |
| * For x in [-0.35,0.35], use a rational approximation. |
| */ |
| pr = spu_madd(x, spu_splats((float)LOG1PF4_P4), spu_splats((float)LOG1PF4_P3)); |
| qr = spu_madd(x, spu_splats((float)LOG1PF4_Q4), spu_splats((float)LOG1PF4_Q3)); |
| pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P2)); |
| qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q2)); |
| pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P1)); |
| qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q1)); |
| pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P0)); |
| qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q0)); |
| rresult = _divf4(pr, qr); |
| |
| /* |
| * Select either direct calculation or rational approximation. |
| */ |
| result = spu_sel(rresult, eresult, use_log); |
| |
| return result; |
| } |
| |
| #endif /* _LOG1PF4_H_ */ |
| #endif /* __SPU__ */ |