diff options
Diffstat (limited to 'target/m68k/softfloat.c')
| -rw-r--r-- | target/m68k/softfloat.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/target/m68k/softfloat.c b/target/m68k/softfloat.c index a3a12a0..00ac9a1 100644 --- a/target/m68k/softfloat.c +++ b/target/m68k/softfloat.c @@ -23,6 +23,9 @@ #include "fpu/softfloat-macros.h" #include "softfloat_fpsp_tables.h" +#define piby2_exp 0x3FFF +#define pi_sig LIT64(0xc90fdaa22168c235) + static floatx80 propagateFloatx80NaNOneArg(floatx80 a, float_status *status) { if (floatx80_is_signaling_nan(a, status)) { @@ -1967,3 +1970,200 @@ floatx80 floatx80_cos(floatx80 a, float_status *status) } } } + +/*---------------------------------------------------------------------------- + | Arc tangent + *----------------------------------------------------------------------------*/ + +floatx80 floatx80_atan(floatx80 a, float_status *status) +{ + flag aSign; + int32_t aExp; + uint64_t aSig; + + int8_t user_rnd_mode, user_rnd_prec; + + int32_t compact, tbl_index; + floatx80 fp0, fp1, fp2, fp3, xsave; + + aSig = extractFloatx80Frac(a); + aExp = extractFloatx80Exp(a); + aSign = extractFloatx80Sign(a); + + if (aExp == 0x7FFF) { + if ((uint64_t) (aSig << 1)) { + return propagateFloatx80NaNOneArg(a, status); + } + a = packFloatx80(aSign, piby2_exp, pi_sig); + float_raise(float_flag_inexact, status); + return floatx80_move(a, status); + } + + if (aExp == 0 && aSig == 0) { + return packFloatx80(aSign, 0, 0); + } + + compact = floatx80_make_compact(aExp, aSig); + + 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; + + if (compact < 0x3FFB8000 || compact > 0x4002FFFF) { + /* |X| >= 16 or |X| < 1/16 */ + if (compact > 0x3FFF8000) { /* |X| >= 16 */ + if (compact > 0x40638000) { /* |X| > 2^(100) */ + fp0 = packFloatx80(aSign, piby2_exp, pi_sig); + fp1 = packFloatx80(aSign, 0x0001, one_sig); + + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_sub(fp0, fp1, status); + + float_raise(float_flag_inexact, status); + + return a; + } else { + fp0 = a; + fp1 = packFloatx80(1, one_exp, one_sig); /* -1 */ + fp1 = floatx80_div(fp1, fp0, status); /* X' = -1/X */ + xsave = fp1; + fp0 = floatx80_mul(fp1, fp1, status); /* Y = X'*X' */ + fp1 = floatx80_mul(fp0, fp0, status); /* Z = Y*Y */ + fp3 = float64_to_floatx80(make_float64(0xBFB70BF398539E6A), + status); /* C5 */ + fp2 = float64_to_floatx80(make_float64(0x3FBC7187962D1D7D), + status); /* C4 */ + fp3 = floatx80_mul(fp3, fp1, status); /* Z*C5 */ + fp2 = floatx80_mul(fp2, fp1, status); /* Z*C4 */ + fp3 = floatx80_add(fp3, float64_to_floatx80( + make_float64(0xBFC24924827107B8), status), + status); /* C3+Z*C5 */ + fp2 = floatx80_add(fp2, float64_to_floatx80( + make_float64(0x3FC999999996263E), status), + status); /* C2+Z*C4 */ + fp1 = floatx80_mul(fp1, fp3, status); /* Z*(C3+Z*C5) */ + fp2 = floatx80_mul(fp2, fp0, status); /* Y*(C2+Z*C4) */ + fp1 = floatx80_add(fp1, float64_to_floatx80( + make_float64(0xBFD5555555555536), status), + status); /* C1+Z*(C3+Z*C5) */ + fp0 = floatx80_mul(fp0, xsave, status); /* X'*Y */ + /* [Y*(C2+Z*C4)]+[C1+Z*(C3+Z*C5)] */ + fp1 = floatx80_add(fp1, fp2, status); + /* X'*Y*([B1+Z*(B3+Z*B5)]+[Y*(B2+Z*(B4+Z*B6))]) ?? */ + fp0 = floatx80_mul(fp0, fp1, status); + fp0 = floatx80_add(fp0, xsave, status); + fp1 = packFloatx80(aSign, piby2_exp, pi_sig); + + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_add(fp0, fp1, status); + + float_raise(float_flag_inexact, status); + + return a; + } + } else { /* |X| < 1/16 */ + if (compact < 0x3FD78000) { /* |X| < 2^(-40) */ + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_move(a, status); + + float_raise(float_flag_inexact, status); + + return a; + } else { + fp0 = a; + xsave = a; + fp0 = floatx80_mul(fp0, fp0, status); /* Y = X*X */ + fp1 = floatx80_mul(fp0, fp0, status); /* Z = Y*Y */ + fp2 = float64_to_floatx80(make_float64(0x3FB344447F876989), + status); /* B6 */ + fp3 = float64_to_floatx80(make_float64(0xBFB744EE7FAF45DB), + status); /* B5 */ + fp2 = floatx80_mul(fp2, fp1, status); /* Z*B6 */ + fp3 = floatx80_mul(fp3, fp1, status); /* Z*B5 */ + fp2 = floatx80_add(fp2, float64_to_floatx80( + make_float64(0x3FBC71C646940220), status), + status); /* B4+Z*B6 */ + fp3 = floatx80_add(fp3, float64_to_floatx80( + make_float64(0xBFC24924921872F9), + status), status); /* B3+Z*B5 */ + fp2 = floatx80_mul(fp2, fp1, status); /* Z*(B4+Z*B6) */ + fp1 = floatx80_mul(fp1, fp3, status); /* Z*(B3+Z*B5) */ + fp2 = floatx80_add(fp2, float64_to_floatx80( + make_float64(0x3FC9999999998FA9), status), + status); /* B2+Z*(B4+Z*B6) */ + fp1 = floatx80_add(fp1, float64_to_floatx80( + make_float64(0xBFD5555555555555), status), + status); /* B1+Z*(B3+Z*B5) */ + fp2 = floatx80_mul(fp2, fp0, status); /* Y*(B2+Z*(B4+Z*B6)) */ + fp0 = floatx80_mul(fp0, xsave, status); /* X*Y */ + /* [B1+Z*(B3+Z*B5)]+[Y*(B2+Z*(B4+Z*B6))] */ + fp1 = floatx80_add(fp1, fp2, status); + /* X*Y*([B1+Z*(B3+Z*B5)]+[Y*(B2+Z*(B4+Z*B6))]) */ + fp0 = floatx80_mul(fp0, fp1, status); + + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_add(fp0, xsave, status); + + float_raise(float_flag_inexact, status); + + return a; + } + } + } else { + aSig &= LIT64(0xF800000000000000); + aSig |= LIT64(0x0400000000000000); + xsave = packFloatx80(aSign, aExp, aSig); /* F */ + fp0 = a; + fp1 = a; /* X */ + fp2 = packFloatx80(0, one_exp, one_sig); /* 1 */ + fp1 = floatx80_mul(fp1, xsave, status); /* X*F */ + fp0 = floatx80_sub(fp0, xsave, status); /* X-F */ + fp1 = floatx80_add(fp1, fp2, status); /* 1 + X*F */ + fp0 = floatx80_div(fp0, fp1, status); /* U = (X-F)/(1+X*F) */ + + tbl_index = compact; + + tbl_index &= 0x7FFF0000; + tbl_index -= 0x3FFB0000; + tbl_index >>= 1; + tbl_index += compact & 0x00007800; + tbl_index >>= 11; + + fp3 = atan_tbl[tbl_index]; + + fp3.high |= aSign ? 0x8000 : 0; /* ATAN(F) */ + + fp1 = floatx80_mul(fp0, fp0, status); /* V = U*U */ + fp2 = float64_to_floatx80(make_float64(0xBFF6687E314987D8), + status); /* A3 */ + fp2 = floatx80_add(fp2, fp1, status); /* A3+V */ + fp2 = floatx80_mul(fp2, fp1, status); /* V*(A3+V) */ + fp1 = floatx80_mul(fp1, fp0, status); /* U*V */ + fp2 = floatx80_add(fp2, float64_to_floatx80( + make_float64(0x4002AC6934A26DB3), status), + status); /* A2+V*(A3+V) */ + fp1 = floatx80_mul(fp1, float64_to_floatx80( + make_float64(0xBFC2476F4E1DA28E), status), + status); /* A1+U*V */ + fp1 = floatx80_mul(fp1, fp2, status); /* A1*U*V*(A2+V*(A3+V)) */ + fp0 = floatx80_add(fp0, fp1, status); /* ATAN(U) */ + + status->float_rounding_mode = user_rnd_mode; + status->floatx80_rounding_precision = user_rnd_prec; + + a = floatx80_add(fp0, fp3, status); /* ATAN(X) */ + + float_raise(float_flag_inexact, status); + + return a; + } +} |