diff options
Diffstat (limited to 'target/m68k/softfloat.c')
| -rw-r--r-- | target/m68k/softfloat.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/target/m68k/softfloat.c b/target/m68k/softfloat.c index 834db12964..180a17c39b 100644 --- a/target/m68k/softfloat.c +++ b/target/m68k/softfloat.c @@ -490,3 +490,171 @@ floatx80 floatx80_lognp1(floatx80 a, float_status *status) return a; } } + +/*---------------------------------------------------------------------------- + | Log base e + *----------------------------------------------------------------------------*/ + +floatx80 floatx80_logn(floatx80 a, float_status *status) +{ + flag aSign; + int32_t aExp; + uint64_t aSig, fSig; + + int8_t user_rnd_mode, user_rnd_prec; + + int32_t compact, j, k, adjk; + floatx80 fp0, fp1, fp2, fp3, f, logof2, klog2, saveu; + + aSig = extractFloatx80Frac(a); + aExp = extractFloatx80Exp(a); + aSign = extractFloatx80Sign(a); + + if (aExp == 0x7FFF) { + if ((uint64_t) (aSig << 1)) { + propagateFloatx80NaNOneArg(a, status); + } + if (aSign == 0) { + return packFloatx80(0, floatx80_infinity.high, + floatx80_infinity.low); + } + } + + adjk = 0; + + if (aExp == 0) { + if (aSig == 0) { /* zero */ + float_raise(float_flag_divbyzero, status); + return packFloatx80(1, floatx80_infinity.high, + floatx80_infinity.low); + } + if ((aSig & one_sig) == 0) { /* denormal */ + normalizeFloatx80Subnormal(aSig, &aExp, &aSig); + adjk = -100; + aExp += 100; + a = packFloatx80(aSign, aExp, aSig); + } + } + + if (aSign) { + float_raise(float_flag_invalid, status); + return floatx80_default_nan(status); + } + + user_rnd_mode = status->float_rounding_mode; + user_rnd_prec = status->floatx80_rounding_precision; + status->float_rounding_mode = float_round_nearest_even; + status->floatx80_rounding_precision = 80; + + compact = floatx80_make_compact(aExp, aSig); + + if (compact < 0x3FFEF07D || compact > 0x3FFF8841) { + /* |X| < 15/16 or |X| > 17/16 */ + k = aExp - 0x3FFF; + k += adjk; + fp1 = int32_to_floatx80(k, status); + + fSig = (aSig & LIT64(0xFE00000000000000)) | LIT64(0x0100000000000000); + j = (fSig >> 56) & 0x7E; /* DISPLACEMENT FOR 1/F */ + + f = packFloatx80(0, 0x3FFF, fSig); /* F */ + fp0 = packFloatx80(0, 0x3FFF, aSig); /* Y */ + + fp0 = floatx80_sub(fp0, f, status); /* Y-F */ + + /* LP1CONT1 */ + fp0 = floatx80_mul(fp0, log_tbl[j], status); /* FP0 IS U = (Y-F)/F */ + logof2 = packFloatx80(0, 0x3FFE, LIT64(0xB17217F7D1CF79AC)); + klog2 = floatx80_mul(fp1, logof2, status); /* FP1 IS K*LOG2 */ + fp2 = floatx80_mul(fp0, fp0, status); /* FP2 IS V=U*U */ + + fp3 = fp2; + fp1 = fp2; + + fp1 = floatx80_mul(fp1, float64_to_floatx80( + make_float64(0x3FC2499AB5E4040B), status), + status); /* V*A6 */ + fp2 = floatx80_mul(fp2, float64_to_floatx80( + make_float64(0xBFC555B5848CB7DB), status), + status); /* V*A5 */ + fp1 = floatx80_add(fp1, float64_to_floatx80( + make_float64(0x3FC99999987D8730), status), + status); /* A4+V*A6 */ + fp2 = floatx80_add(fp2, float64_to_floatx80( + make_float64(0xBFCFFFFFFF6F7E97), status), + status); /* A3+V*A5 */ + fp1 = floatx80_mul(fp1, fp3, status); /* V*(A4+V*A6) */ + fp2 = floatx80_mul(fp2, fp3, status); /* V*(A3+V*A5) */ + fp1 = floatx80_add(fp1, float64_to_floatx80( + make_float64(0x3FD55555555555A4), status), + status); /* A2+V*(A4+V*A6) */ + fp2 = floatx80_add(fp2, float64_to_floatx80( + make_float64(0xBFE0000000000008), status), + status); /* A1+V*(A3+V*A5) */ + fp1 = floatx80_mul(fp1, fp3, status); /* V*(A2+V*(A4+V*A6)) */ + fp2 = floatx80_mul(fp2, fp3, status); /* V*(A1+V*(A3+V*A5)) */ + fp1 = floatx80_mul(fp1, fp0, status); /* U*V*(A2+V*(A4+V*A6)) */ + fp0 = floatx80_add(fp0, fp2, status); /* U+V*(A1+V*(A3+V*A5)) */ + + fp1 = floatx80_add(fp1, log_tbl[j + 1], + status); /* LOG(F)+U*V*(A2+V*(A4+V*A6)) */ + fp0 = floatx80_add(fp0, fp1, status); /* FP0 IS LOG(F) + LOG(1+U) */ + + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_add(fp0, klog2, status); + + float_raise(float_flag_inexact, status); + + return a; + } else { /* |X-1| >= 1/16 */ + fp0 = a; + fp1 = a; + fp1 = floatx80_sub(fp1, float32_to_floatx80(make_float32(0x3F800000), + status), status); /* FP1 IS X-1 */ + fp0 = floatx80_add(fp0, float32_to_floatx80(make_float32(0x3F800000), + status), status); /* FP0 IS X+1 */ + fp1 = floatx80_add(fp1, fp1, status); /* FP1 IS 2(X-1) */ + + /* LP1CONT2 */ + fp1 = floatx80_div(fp1, fp0, status); /* U */ + saveu = fp1; + fp0 = floatx80_mul(fp1, fp1, status); /* FP0 IS V = U*U */ + fp1 = floatx80_mul(fp0, fp0, status); /* FP1 IS W = V*V */ + + fp3 = float64_to_floatx80(make_float64(0x3F175496ADD7DAD6), + status); /* B5 */ + fp2 = float64_to_floatx80(make_float64(0x3F3C71C2FE80C7E0), + status); /* B4 */ + fp3 = floatx80_mul(fp3, fp1, status); /* W*B5 */ + fp2 = floatx80_mul(fp2, fp1, status); /* W*B4 */ + fp3 = floatx80_add(fp3, float64_to_floatx80( + make_float64(0x3F624924928BCCFF), status), + status); /* B3+W*B5 */ + fp2 = floatx80_add(fp2, float64_to_floatx80( + make_float64(0x3F899999999995EC), status), + status); /* B2+W*B4 */ + fp1 = floatx80_mul(fp1, fp3, status); /* W*(B3+W*B5) */ + fp2 = floatx80_mul(fp2, fp0, status); /* V*(B2+W*B4) */ + fp1 = floatx80_add(fp1, float64_to_floatx80( + make_float64(0x3FB5555555555555), status), + status); /* B1+W*(B3+W*B5) */ + + fp0 = floatx80_mul(fp0, saveu, status); /* FP0 IS U*V */ + fp1 = floatx80_add(fp1, fp2, status); /* B1+W*(B3+W*B5) + V*(B2+W*B4) */ + fp0 = floatx80_mul(fp0, fp1, + status); /* U*V*([B1+W*(B3+W*B5)] + [V*(B2+W*B4)]) */ + + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_add(fp0, saveu, status); + + /*if (!floatx80_is_zero(a)) { */ + float_raise(float_flag_inexact, status); + /*} */ + + return a; + } +} |