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| /* International Business Machines Corporation, */ |
| /* Sony Computer Entertainment, Incorporated, */ |
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| /* -------------------------------------------------------------- */ |
| /* PROLOG END TAG zYx */ |
| #ifdef __SPU__ |
| |
| #ifndef _DIVD2_H_ |
| #define _DIVD2_H_ 1 |
| |
| #include <spu_intrinsics.h> |
| |
| /* |
| * FUNCTION |
| * vector double _divd2(vector double a, vector double b) |
| * |
| * DESCRIPTION |
| * _divd2 divides the vector dividend a by the vector divisor b and |
| * returns the resulting vector quotient. Maximum error about 0.5 ulp |
| * over entire double range including denorms, compared to true result |
| * in round-to-nearest rounding mode. Handles Inf or NaN operands and |
| * results correctly. |
| */ |
| static __inline vector double _divd2(vector double a_in, vector double b_in) |
| { |
| /* Variables */ |
| vec_int4 exp, exp_bias; |
| vec_uint4 no_underflow, overflow; |
| vec_float4 mant_bf, inv_bf; |
| vec_ullong2 exp_a, exp_b; |
| vec_ullong2 a_nan, a_zero, a_inf, a_denorm; |
| vec_ullong2 b_nan, b_zero, b_inf, b_denorm; |
| vec_ullong2 nan; |
| vec_double2 a, b; |
| vec_double2 mant_a, mant_b, inv_b, q0, q1, q2, mult; |
| |
| /* Constants */ |
| vec_float4 onef = spu_splats(1.0f); |
| vec_ullong2 exp_mask = spu_splats(0x7FF0000000000000ULL); |
| vec_double2 one = spu_splats(1.0); |
| |
| #ifdef __SPU_EDP__ |
| vec_double2 denorm_scale = (vec_double2)spu_splats(0x4330000000000000ULL); |
| |
| /* Identify all possible special values that must be accomodated including: |
| * +-0, +-infinity, +-denorm, and NaNs. |
| */ |
| a_nan = spu_testsv(a_in, (SPU_SV_NAN)); |
| a_zero = spu_testsv(a_in, (SPU_SV_NEG_ZERO | SPU_SV_POS_ZERO)); |
| a_inf = spu_testsv(a_in, (SPU_SV_NEG_INFINITY | SPU_SV_POS_INFINITY)); |
| a_denorm = spu_testsv(a_in, (SPU_SV_NEG_DENORM | SPU_SV_POS_DENORM)); |
| |
| b_nan = spu_testsv(b_in, (SPU_SV_NAN)); |
| b_zero = spu_testsv(b_in, (SPU_SV_NEG_ZERO | SPU_SV_POS_ZERO)); |
| b_inf = spu_testsv(b_in, (SPU_SV_NEG_INFINITY | SPU_SV_POS_INFINITY)); |
| b_denorm = spu_testsv(b_in, (SPU_SV_NEG_DENORM | SPU_SV_POS_DENORM)); |
| |
| /* Scale denorm inputs to into normalized numbers by conditionally scaling the |
| * input parameters. |
| */ |
| a = spu_sel(a_in, spu_mul(a_in, denorm_scale), a_denorm); |
| b = spu_sel(b_in, spu_mul(b_in, denorm_scale), b_denorm); |
| |
| #else /* !__SPU_EDP__ */ |
| vec_uint4 a_exp, b_exp; |
| vec_ullong2 a_mant_0, b_mant_0; |
| vec_ullong2 a_exp_1s, b_exp_1s; |
| vec_ullong2 sign_exp_mask; |
| |
| vec_uint4 exp_mask_u32 = spu_splats((unsigned int)0x7FF00000); |
| vec_uchar16 splat_hi = (vec_uchar16){0,1,2,3, 0,1,2,3, 8, 9,10,11, 8,9,10,11}; |
| vec_uchar16 swap_32 = (vec_uchar16){4,5,6,7, 0,1,2,3, 12,13,14,15, 8,9,10,11}; |
| vec_ullong2 sign_mask = spu_splats(0x8000000000000000ULL); |
| vec_double2 exp_53 = (vec_double2)spu_splats(0x0350000000000000ULL); |
| |
| sign_exp_mask = spu_or(sign_mask, exp_mask); |
| |
| /* Extract the floating point components from each of the operands including |
| * exponent and mantissa. |
| */ |
| a_exp = (vec_uint4)spu_and((vec_uint4)a_in, exp_mask_u32); |
| a_exp = spu_shuffle(a_exp, a_exp, splat_hi); |
| b_exp = (vec_uint4)spu_and((vec_uint4)b_in, exp_mask_u32); |
| b_exp = spu_shuffle(b_exp, b_exp, splat_hi); |
| |
| a_mant_0 = (vec_ullong2)spu_cmpeq((vec_uint4)spu_andc((vec_ullong2)a_in, sign_exp_mask), 0); |
| a_mant_0 = spu_and(a_mant_0, spu_shuffle(a_mant_0, a_mant_0, swap_32)); |
| |
| b_mant_0 = (vec_ullong2)spu_cmpeq((vec_uint4)spu_andc((vec_ullong2)b_in, sign_exp_mask), 0); |
| b_mant_0 = spu_and(b_mant_0, spu_shuffle(b_mant_0, b_mant_0, swap_32)); |
| |
| a_exp_1s = (vec_ullong2)spu_cmpeq(a_exp, exp_mask_u32); |
| b_exp_1s = (vec_ullong2)spu_cmpeq(b_exp, exp_mask_u32); |
| |
| /* Identify all possible special values that must be accomodated including: |
| * +-denorm, +-0, +-infinity, and NaNs. |
| */ |
| a_denorm = (vec_ullong2)spu_cmpeq(a_exp, 0); /* really is a_exp_0 */ |
| a_nan = spu_andc(a_exp_1s, a_mant_0); |
| a_zero = spu_and (a_denorm, a_mant_0); |
| a_inf = spu_and (a_exp_1s, a_mant_0); |
| |
| b_denorm = (vec_ullong2)spu_cmpeq(b_exp, 0); /* really is b_exp_0 */ |
| b_nan = spu_andc(b_exp_1s, b_mant_0); |
| b_zero = spu_and (b_denorm, b_mant_0); |
| b_inf = spu_and (b_exp_1s, b_mant_0); |
| |
| /* Scale denorm inputs to into normalized numbers by conditionally scaling the |
| * input parameters. |
| */ |
| a = spu_sub(spu_or(a_in, exp_53), spu_sel(exp_53, a_in, sign_mask)); |
| a = spu_sel(a_in, a, a_denorm); |
| |
| b = spu_sub(spu_or(b_in, exp_53), spu_sel(exp_53, b_in, sign_mask)); |
| b = spu_sel(b_in, b, b_denorm); |
| |
| #endif /* __SPU_EDP__ */ |
| |
| /* Extract the divisor and dividend exponent and force parameters into the signed |
| * range [1.0,2.0) or [-1.0,2.0). |
| */ |
| exp_a = spu_and((vec_ullong2)a, exp_mask); |
| exp_b = spu_and((vec_ullong2)b, exp_mask); |
| |
| mant_a = spu_sel(a, one, (vec_ullong2)exp_mask); |
| mant_b = spu_sel(b, one, (vec_ullong2)exp_mask); |
| |
| /* Approximate the single reciprocal of b by using |
| * the single precision reciprocal estimate followed by one |
| * single precision iteration of Newton-Raphson. |
| */ |
| mant_bf = spu_roundtf(mant_b); |
| inv_bf = spu_re(mant_bf); |
| inv_bf = spu_madd(spu_nmsub(mant_bf, inv_bf, onef), inv_bf, inv_bf); |
| |
| /* Perform 2 more Newton-Raphson iterations in double precision. The |
| * result (q1) is in the range (0.5, 2.0). |
| */ |
| inv_b = spu_extend(inv_bf); |
| inv_b = spu_madd(spu_nmsub(mant_b, inv_b, one), inv_b, inv_b); |
| q0 = spu_mul(mant_a, inv_b); |
| q1 = spu_madd(spu_nmsub(mant_b, q0, mant_a), inv_b, q0); |
| |
| |
| /* Determine the exponent correction factor that must be applied |
| * to q1 by taking into account the exponent of the normalized inputs |
| * and the scale factors that were applied to normalize them. |
| */ |
| exp = spu_rlmaska(spu_sub((vec_int4)exp_a, (vec_int4)exp_b), -20); |
| exp = spu_add(exp, (vec_int4)spu_add(spu_and((vec_int4)a_denorm, -0x34), spu_and((vec_int4)b_denorm, 0x34))); |
| |
| /* Bias the quotient exponent depending on the sign of the exponent correction |
| * factor so that a single multiplier will ensure the entire double precision |
| * domain (including denorms) can be achieved. |
| * |
| * exp bias q1 adjust exp |
| * ===== ======== ========== |
| * positive 2^+65 -65 |
| * negative 2^-64 +64 |
| */ |
| exp_bias = spu_xor(spu_rlmaska(exp, -31), 64); |
| |
| |
| exp = spu_sub(exp, exp_bias); |
| |
| q1 = spu_sel(q1, (vec_double2)spu_add((vec_int4)q1, spu_sl(exp_bias, 20)), exp_mask); |
| |
| /* Compute a multiplier (mult) to applied to the quotient (q1) to produce the |
| * expected result. |
| */ |
| exp = spu_add(exp, 0x3FF); |
| no_underflow = spu_cmpgt(exp, 0); |
| overflow = spu_cmpgt(exp, 0x7FF); |
| exp = spu_and(spu_sl(exp, 20), (vec_int4)no_underflow); |
| exp = spu_and(exp, (vec_int4)exp_mask); |
| mult = spu_sel((vec_double2)exp, (vec_double2)exp_mask, (vec_ullong2)overflow); |
| |
| /* Handle special value conditions. These include: |
| * |
| * 1) IF either operand is a NaN OR both operands are 0 or INFINITY THEN a NaN |
| * results. |
| * 2) ELSE IF the dividend is an INFINITY OR the divisor is 0 THEN a INFINITY results. |
| * 3) ELSE IF the dividend is 0 OR the divisor is INFINITY THEN a 0 results. |
| */ |
| mult = spu_andc(mult, (vec_double2)spu_or(a_zero, b_inf)); |
| mult = spu_sel(mult, (vec_double2)exp_mask, spu_or(a_inf, b_zero)); |
| |
| nan = spu_or(a_nan, b_nan); |
| nan = spu_or(nan, spu_and(a_zero, b_zero)); |
| nan = spu_or(nan, spu_and(a_inf, b_inf)); |
| |
| mult = spu_or(mult, (vec_double2)nan); |
| |
| /* Scale the final quotient */ |
| |
| q2 = spu_mul(q1, mult); |
| |
| return (q2); |
| } |
| |
| #endif /* _DIVD2_H_ */ |
| #endif /* __SPU__ */ |