From 61238a798636700375ab418bca76689c36cf434d Mon Sep 17 00:00:00 2001
From: Ulrich Weigand <uweigand@de.ibm.com>
Date: Thu, 26 Mar 2009 14:36:27 +0000
Subject: [PATCH] divv2df3.c: New file.
* config/spu/divv2df3.c: New file.
* config/spu/t-spu-elf (LIB2FUNCS_STATIC_EXTRA): Add it.
(DPBIT_FUNCS): Filter out _div_df.
From-SVN: r145089
---
gcc/ChangeLog | 6 ++
gcc/config/spu/divv2df3.c | 198 ++++++++++++++++++++++++++++++++++++++
gcc/config/spu/t-spu-elf | 7 +-
3 files changed, 210 insertions(+), 1 deletion(-)
create mode 100644 gcc/config/spu/divv2df3.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1f525bfb35d4..877fce3dd1a2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2009-03-26 Ulrich Weigand <Ulrich.Weigand@de.ibm.com>
+
+ * config/spu/divv2df3.c: New file.
+ * config/spu/t-spu-elf (LIB2FUNCS_STATIC_EXTRA): Add it.
+ (DPBIT_FUNCS): Filter out _div_df.
+
2009-03-26 Bernd Schmidt <bernd.schmidt@analog.com>
* config/bfin/bfin.c (bfin_optimize_loop): If the LSETUP goes before
diff --git a/gcc/config/spu/divv2df3.c b/gcc/config/spu/divv2df3.c
new file mode 100644
index 000000000000..cd7126bb7338
--- /dev/null
+++ b/gcc/config/spu/divv2df3.c
@@ -0,0 +1,198 @@
+/* Copyright (C) 2009 Free Software Foundation, Inc.
+
+ This file is free software; you can redistribute it and/or modify it under
+ the terms of the GNU General Public License as published by the Free
+ Software Foundation; either version 2 of the License, or (at your option)
+ any later version.
+
+ This file is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this file; see the file COPYING. If not, write to the Free
+ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+ 02110-1301, USA. */
+
+/* As a special exception, if you link this library with files compiled with
+ GCC to produce an executable, this does not cause the resulting executable
+ to be covered by the GNU General Public License. The exception does not
+ however invalidate any other reasons why the executable file might be covered
+ by the GNU General Public License. */
+
+
+#include <spu_intrinsics.h>
+
+vector double __divv2df3 (vector double a_in, vector double b_in);
+
+/* __divv2df3 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. */
+
+vector double
+__divv2df3 (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, a_denorm0;
+ vec_ullong2 b_nan, b_zero, b_inf, b_denorm, b_denorm0;
+ vec_ullong2 nan;
+ 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_double2 a, b;
+ vec_double2 mant_a, mant_b, inv_b, q0, q1, q2, mult;
+
+ /* Constants */
+ 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 exp_mask = spu_splats(0x7FF0000000000000ULL);
+ vec_ullong2 sign_mask = spu_splats(0x8000000000000000ULL);
+ vec_float4 onef = spu_splats(1.0f);
+ vec_double2 one = spu_splats(1.0);
+ 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_denorm0= (vec_ullong2)spu_cmpeq(a_exp, 0);
+ a_nan = spu_andc(a_exp_1s, a_mant_0);
+ a_zero = spu_and (a_denorm0, a_mant_0);
+ a_inf = spu_and (a_exp_1s, a_mant_0);
+ a_denorm = spu_andc(a_denorm0, a_zero);
+
+ b_denorm0= (vec_ullong2)spu_cmpeq(b_exp, 0);
+ b_nan = spu_andc(b_exp_1s, b_mant_0);
+ b_zero = spu_and (b_denorm0, b_mant_0);
+ b_inf = spu_and (b_exp_1s, b_mant_0);
+ b_denorm = spu_andc(b_denorm0, b_zero);
+
+ /* 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);
+
+ /* 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. On overflow, clamp the multiplier to the maximum non-infinite
+ * number in case the rounding mode is not round-to-nearest.
+ */
+ exp = spu_add(exp, 0x3FF);
+ no_underflow = spu_cmpgt(exp, 0);
+ overflow = spu_cmpgt(exp, 0x7FE);
+ 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)(spu_add((vec_uint4)exp_mask, -1)), (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);
+}
+
+
+/* We use the same function for vector and scalar division. Provide the
+ scalar entry point as an alias. */
+double __divdf3 (double a, double b)
+ __attribute__ ((__alias__ ("__divv2df3")));
+
+/* Some toolchain builds used the __fast_divdf3 name for this helper function.
+ Provide this as another alternate entry point for compatibility. */
+double __fast_divdf3 (double a, double b)
+ __attribute__ ((__alias__ ("__divv2df3")));
+
diff --git a/gcc/config/spu/t-spu-elf b/gcc/config/spu/t-spu-elf
index 2e1928707dfc..f8c5ba5b01db 100644
--- a/gcc/config/spu/t-spu-elf
+++ b/gcc/config/spu/t-spu-elf
@@ -29,6 +29,10 @@ TARGET_LIBGCC2_CFLAGS = -fPIC -mwarn-reloc -D__IN_LIBGCC2
# own versions below.
LIB2FUNCS_EXCLUDE = _floatdisf _floatundisf
+# We provide our own version of __divdf3 that performs better and has
+# better support for non-default rounding modes.
+DPBIT_FUNCS := $(filter-out _div_df, $(DPBIT_FUNCS))
+
LIB2FUNCS_STATIC_EXTRA = $(srcdir)/config/spu/float_unssidf.c \
$(srcdir)/config/spu/float_unsdidf.c \
$(srcdir)/config/spu/float_unsdisf.c \
@@ -39,7 +43,8 @@ LIB2FUNCS_STATIC_EXTRA = $(srcdir)/config/spu/float_unssidf.c \
$(srcdir)/config/spu/mfc_multi_tag_reserve.c \
$(srcdir)/config/spu/mfc_multi_tag_release.c \
$(srcdir)/config/spu/multi3.c \
- $(srcdir)/config/spu/divmodti4.c
+ $(srcdir)/config/spu/divmodti4.c \
+ $(srcdir)/config/spu/divv2df3.c
LIB2ADDEH = $(srcdir)/unwind-dw2.c $(srcdir)/unwind-dw2-fde.c \
$(srcdir)/unwind-sjlj.c $(srcdir)/unwind-c.c
--
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