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| /* PROLOG END TAG zYx */ |
| #ifdef __SPU__ |
| #ifndef _NEXTAFTERF4_H_ |
| #define _NEXTAFTERF4_H_ 1 |
| |
| #include <spu_intrinsics.h> |
| |
| /* |
| * FUNCTION |
| * vector float _nextafterf4(vector float x, vector float y) |
| * |
| * DESCRIPTION |
| * The nextafterf4 function returns a vector containing the next representable |
| * floating-point number after the element of x, in the direction of the |
| * corresponding element y. |
| * |
| * Special Cases: |
| * - Infinity and NaN are not supported in single-precision on SPU. They are treated |
| * as normal numbers. |
| * - x != y, and result = 0 is considered an underflow. |
| * |
| * |
| */ |
| |
| static __inline vector float _nextafterf4(vector float x, vector float y) |
| { |
| vec_float4 n1ulp = (vec_float4)spu_splats(0x80000001); |
| vec_float4 zerof = spu_splats(0.0f); |
| vec_int4 one = spu_splats(1); |
| vec_uint4 xlt0, xgty, xeqy, xeq0; |
| vec_int4 xint; |
| vec_int4 delta, deltap1; |
| vec_float4 result; |
| |
| /* |
| * The idea here is to treat x as a signed int value, which allows us to |
| * add or subtact one to/from it to get the next representable value. |
| */ |
| |
| xeq0 = spu_cmpeq(x, zerof); |
| xlt0 = spu_cmpgt(zerof, x); |
| xeqy = spu_cmpeq(x, y); |
| xgty = spu_cmpgt(x, y); |
| |
| /* If x = -0.0, set x = 0.0 */ |
| x = spu_andc(x, (vec_float4)xeq0); |
| |
| xint = (vec_int4)x; |
| |
| /* Determine value to add to x */ |
| delta = (vec_int4)spu_xor(xgty, xlt0); |
| deltap1 = spu_add(delta,one); |
| delta = spu_sel(deltap1, delta, (vec_uint4)delta); |
| |
| xint = spu_add(xint, delta); |
| |
| /* Fix the case of x = 0, and answer should be -1 ulp */ |
| result = spu_sel((vec_float4)xint, n1ulp, spu_and((vec_uint4)delta, xeq0)); |
| |
| /* |
| * Special Cases |
| */ |
| |
| /* x = y */ |
| result = spu_sel(result, y, xeqy); |
| |
| return result; |
| |
| } |
| |
| #endif /* _NEXTAFTERF4_H_ */ |
| #endif /* __SPU__ */ |