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40 /* PROLOG END TAG zYx */
41 #ifdef __SPU__
42 #ifndef _TRUNCD2_H_
43 #define _TRUNCD2_H_ 1
44
45 #include <spu_intrinsics.h>
46
47 /*
48 * FUNCTION
49 * vector double _truncd2(vector double x)
50 *
51 * DESCRIPTION
52 * The _truncd2 function truncates the elements of the input vector
53 * downwards (towards zero) to the nearest integer.
54 *
55 */
_truncd2(vector double in)56 static __inline vector double _truncd2(vector double in)
57 {
58 vec_uchar16 splat_hi = (vec_uchar16) { 0,1,2,3,0,1,2,3, 8,9,10,11, 8,9,10,11 };
59 vec_int4 exp, shift;
60 vec_uint4 sign = (vec_uint4) { 0x80000000, 0, 0x80000000, 0 };
61 vec_uint4 or_mask, and_mask, mask;
62 vec_double2 in_hi, out;
63
64 /* Construct a mask to remove the fraction bits. The mask
65 * depends on the exponent of the floating point
66 * input value.
67 */
68 in_hi = spu_shuffle(in, in, splat_hi);
69 exp = spu_and(spu_rlmask((vec_int4)in_hi, -20), 0x7FF);
70
71 shift = spu_sub(((vec_int4) { 1023, 1043, 1023, 1043 }), exp);
72 or_mask = spu_andc(spu_cmpgt(shift, 0), sign);
73
74 and_mask = spu_rlmask(((vec_uint4) { 0xFFFFF, -1, 0xFFFFF, -1 }), shift);
75 mask = spu_or(spu_and(and_mask, spu_cmpgt(shift, -32)), or_mask);
76
77 /* Apply the mask and return the result.
78 */
79 out = spu_andc(in, (vec_double2)(mask));
80
81 return (out);
82 }
83
84
85 #endif /* _TRUNCD2_H_ */
86 #endif /* __SPU__ */
87
