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| 1 | +//===----------------------------------------------------------------------===// |
| 2 | +// |
| 3 | +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | +// See https://llvm.org/LICENSE.txt for license information. |
| 5 | +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | +// |
| 7 | +//===----------------------------------------------------------------------===// |
| 8 | + |
| 9 | +#if __CLC_FPSIZE == 32 |
| 10 | + |
| 11 | +_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_cbrt(__CLC_GENTYPE x) { |
| 12 | + __CLC_UINTN xi = __CLC_AS_UINTN(x); |
| 13 | + __CLC_UINTN axi = __CLC_AS_UINTN(__clc_fabs(x)); |
| 14 | + __CLC_UINTN xsign = axi ^ xi; |
| 15 | + xi = axi; |
| 16 | + |
| 17 | + __CLC_INTN m = __CLC_AS_INTN(xi >> EXPSHIFTBITS_SP32) - EXPBIAS_SP32; |
| 18 | + |
| 19 | + // Treat subnormals |
| 20 | + __CLC_UINTN xisub = __CLC_AS_UINTN(__CLC_AS_GENTYPE(xi | 0x3f800000) - 1.0f); |
| 21 | + __CLC_INTN msub = __CLC_AS_INTN(xisub >> EXPSHIFTBITS_SP32) - 253; |
| 22 | + __CLC_INTN c = m == -127; |
| 23 | + xi = c ? xisub : xi; |
| 24 | + m = c ? msub : m; |
| 25 | + |
| 26 | + __CLC_INTN m3 = m / 3; |
| 27 | + __CLC_INTN rem = m - m3 * 3; |
| 28 | + __CLC_GENTYPE mf = __CLC_AS_GENTYPE((m3 + EXPBIAS_SP32) << EXPSHIFTBITS_SP32); |
| 29 | + |
| 30 | + __CLC_UINTN indx = (xi & 0x007f0000) + ((xi & 0x00008000) << 1); |
| 31 | + __CLC_GENTYPE f = __CLC_AS_GENTYPE((xi & MANTBITS_SP32) | 0x3f000000) - |
| 32 | + __CLC_AS_GENTYPE(indx | 0x3f000000); |
| 33 | + |
| 34 | + indx >>= 16; |
| 35 | + __CLC_GENTYPE r = f * USE_TABLE(log_inv_tbl, __CLC_AS_INTN(indx)); |
| 36 | + __CLC_GENTYPE poly = __clc_mad(__clc_mad(r, 0x1.f9add4p-5f, -0x1.c71c72p-4f), |
| 37 | + r * r, r * 0x1.555556p-2f); |
| 38 | + |
| 39 | + // This could also be done with a 5-element table |
| 40 | + __CLC_GENTYPE remH = 0x1.428000p-1f; |
| 41 | + __CLC_GENTYPE remT = 0x1.45f31ap-14f; |
| 42 | + |
| 43 | + remH = rem == -1 ? 0x1.964000p-1f : remH; |
| 44 | + remT = rem == -1 ? 0x1.fea53ep-13f : remT; |
| 45 | + |
| 46 | + remH = rem == 0 ? 0x1.000000p+0f : remH; |
| 47 | + remT = rem == 0 ? 0x0.000000p+0f : remT; |
| 48 | + |
| 49 | + remH = rem == 1 ? 0x1.428000p+0f : remH; |
| 50 | + remT = rem == 1 ? 0x1.45f31ap-13f : remT; |
| 51 | + |
| 52 | + remH = rem == 2 ? 0x1.964000p+0f : remH; |
| 53 | + remT = rem == 2 ? 0x1.fea53ep-12f : remT; |
| 54 | + |
| 55 | + __CLC_GENTYPE cbrtH = USE_TABLE(cbrt_tbl_head, __CLC_AS_INTN(indx)); |
| 56 | + __CLC_GENTYPE cbrtT = USE_TABLE(cbrt_tbl_tail, __CLC_AS_INTN(indx)); |
| 57 | + |
| 58 | + __CLC_GENTYPE bH = cbrtH * remH; |
| 59 | + __CLC_GENTYPE bT = |
| 60 | + __clc_mad(cbrtH, remT, __clc_mad(cbrtT, remH, cbrtT * remT)); |
| 61 | + |
| 62 | + __CLC_GENTYPE z = __clc_mad(poly, bH, __clc_mad(poly, bT, bT)) + bH; |
| 63 | + z *= mf; |
| 64 | + z = __CLC_AS_GENTYPE(__CLC_AS_UINTN(z) | xsign); |
| 65 | + c = axi >= EXPBITS_SP32 || axi == 0; |
| 66 | + z = c ? x : z; |
| 67 | + return z; |
| 68 | +} |
| 69 | + |
| 70 | +#elif __CLC_FPSIZE == 64 |
| 71 | + |
| 72 | +_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_cbrt(__CLC_GENTYPE x) { |
| 73 | + __CLC_LONGN return_x = __clc_isinf(x) || __clc_isnan(x) || x == 0.0; |
| 74 | + __CLC_ULONGN ux = __CLC_AS_ULONGN(__clc_fabs(x)); |
| 75 | + __CLC_INTN m = __CLC_CONVERT_INTN(ux >> EXPSHIFTBITS_DP64) - 1023; |
| 76 | + |
| 77 | + // Treat subnormals |
| 78 | + __CLC_ULONGN uxs = |
| 79 | + __CLC_AS_ULONGN(__CLC_AS_GENTYPE(0x3ff0000000000000UL | ux) - 1.0); |
| 80 | + __CLC_INTN ms = m + __CLC_CONVERT_INTN(uxs >> EXPSHIFTBITS_DP64) - 1022; |
| 81 | + |
| 82 | + __CLC_INTN c = m == -1023; |
| 83 | + ux = __CLC_CONVERT_LONGN(c) ? uxs : ux; |
| 84 | + m = c ? ms : m; |
| 85 | + |
| 86 | + __CLC_INTN mby3 = m / 3; |
| 87 | + __CLC_INTN rem = m - 3 * mby3; |
| 88 | + |
| 89 | + __CLC_GENTYPE mf = __CLC_AS_GENTYPE(__CLC_CONVERT_ULONGN(mby3 + 1023) << 52); |
| 90 | + |
| 91 | + ux &= 0x000fffffffffffffUL; |
| 92 | + __CLC_GENTYPE Y = __CLC_AS_GENTYPE(0x3fe0000000000000UL | ux); |
| 93 | + |
| 94 | + // nearest integer |
| 95 | + __CLC_INTN index = __CLC_CONVERT_INTN(ux >> 43); |
| 96 | + index = (0x100 | (index >> 1)) + (index & 1); |
| 97 | + __CLC_GENTYPE F = __CLC_CONVERT_GENTYPE(index) * 0x1.0p-9; |
| 98 | + |
| 99 | + __CLC_GENTYPE f = Y - F; |
| 100 | + __CLC_GENTYPE r = f * USE_TABLE(cbrt_inv_tbl, index - 256); |
| 101 | + |
| 102 | + __CLC_GENTYPE z = |
| 103 | + r * __clc_fma( |
| 104 | + r, |
| 105 | + __clc_fma(r, |
| 106 | + __clc_fma(r, |
| 107 | + __clc_fma(r, |
| 108 | + __clc_fma(r, -0x1.8090d6221a247p-6, |
| 109 | + 0x1.ee7113506ac13p-6), |
| 110 | + -0x1.511e8d2b3183bp-5), |
| 111 | + 0x1.f9add3c0ca458p-5), |
| 112 | + -0x1.c71c71c71c71cp-4), |
| 113 | + 0x1.5555555555555p-2); |
| 114 | + |
| 115 | + __CLC_GENTYPE Rem_h = USE_TABLE(cbrt_rem_tbl_head, rem + 2); |
| 116 | + __CLC_GENTYPE Rem_t = USE_TABLE(cbrt_rem_tbl_tail, rem + 2); |
| 117 | + |
| 118 | + __CLC_GENTYPE F_h = USE_TABLE(cbrt_dbl_tbl_head, index - 256); |
| 119 | + __CLC_GENTYPE F_t = USE_TABLE(cbrt_dbl_tbl_tail, index - 256); |
| 120 | + |
| 121 | + __CLC_GENTYPE b_h = F_h * Rem_h; |
| 122 | + __CLC_GENTYPE b_t = __clc_fma(Rem_t, F_h, __clc_fma(F_t, Rem_h, F_t * Rem_t)); |
| 123 | + |
| 124 | + __CLC_GENTYPE ans = __clc_fma(z, b_h, __clc_fma(z, b_t, b_t)) + b_h; |
| 125 | + ans = __clc_copysign(ans * mf, x); |
| 126 | + return return_x ? x : ans; |
| 127 | +} |
| 128 | + |
| 129 | +#elif __CLC_FPSIZE == 16 |
| 130 | + |
| 131 | +_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_cbrt(__CLC_GENTYPE x) { |
| 132 | + return __CLC_CONVERT_GENTYPE(__clc_cbrt(__CLC_CONVERT_FLOATN(x))); |
| 133 | +} |
| 134 | + |
| 135 | +#endif |
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