Spurred by Akari Takahashi's patch to config/sh/divtab.cc, this removes
divtab.cc completely.
divtab.cc was used to calculate a division table for the sh5 media
processor. GCC dropped support for that (unmanufactured) chip back in
2016 and this file simply got missed AFAICT.
Pushed to the trunk,
Jeff
commit 99dec205a12f7dfa39fd43fc7c36d9974aaec526
Author: Jeff Law <j...@ventanamicro.com>
Date: Tue Jun 13 11:10:21 2023 -0600
Remove sh5media divtab code
Spurred by Akari Takahashi's patch to config/sh/divtab.cc, this removes
divtab.cc completely.
divtab.cc was used to calculate a division table for the sh5 media
processor. GCC dropped support for that (unmanufactured) chip back
in 2016 and this file simply got missed AFAICT.
gcc/
* config/sh/divtab.cc: Remove.
diff --git a/gcc/config/sh/divtab.cc b/gcc/config/sh/divtab.cc
deleted file mode 100644
index a69dd541370..00000000000
--- a/gcc/config/sh/divtab.cc
+++ /dev/null
@@ -1,203 +0,0 @@
-/* Copyright (C) 2003-2023 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 3, 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.
-
-Under Section 7 of GPL version 3, you are granted additional
-permissions described in the GCC Runtime Library Exception, version
-3.1, as published by the Free Software Foundation.
-
-You should have received a copy of the GNU General Public License and
-a copy of the GCC Runtime Library Exception along with this program;
-see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
-<http://www.gnu.org/licenses/>. */
-
-
-/* Calculate division table for SH5Media integer division
- Contributed by Joern Rennecke
- joern.renne...@superh.com */
-
-#include <stdio.h>
-#include <math.h>
-
-#define BITS 5
-#define N_ENTRIES (1 << BITS)
-#define CUTOFF_BITS 20
-
-#define BIAS (-330)
-
-double max_defect = 0.;
-double max_defect_x;
-
-double min_defect = 1e9;
-double min_defect_x;
-
-double max_defect2 = 0.;
-double max_defect2_x;
-
-double min_defect2 = 0.;
-double min_defect2_x;
-
-double min_defect3 = 01e9;
-double min_defect3_x;
-int min_defect3_val;
-
-double max_defect3 = 0.;
-double max_defect3_x;
-int max_defect3_val;
-
-static double
-note_defect3 (int val, double d2, double y2d, double x)
-{
- int cutoff_val = val >> CUTOFF_BITS;
- double cutoff;
- double defect;
-
- if (val < 0)
- cutoff_val++;
- cutoff = (cutoff_val * (1<<CUTOFF_BITS) - val) * y2d;
- defect = cutoff + val * d2;
- if (val < 0)
- defect = - defect;
- if (defect > max_defect3)
- {
- max_defect3 = defect;
- max_defect3_x = x;
- max_defect3_val = val;
- }
- if (defect < min_defect3)
- {
- min_defect3 = defect;
- min_defect3_x = x;
- min_defect3_val = val;
- }
-}
-
-/* This function assumes 32-bit integers. */
-static double
-calc_defect (double x, int constant, int factor)
-{
- double y0 = (constant - (int) floor ((x * factor * 64.))) / 16384.;
- double y1 = 2 * y0 -y0 * y0 * (x + BIAS / (1.*(1LL<<30)));
- double y2d0, y2d;
- int y2d1;
- double d, d2;
-
- y1 = floor (y1 * (1024 * 1024 * 1024)) / (1024 * 1024 * 1024);
- d = y1 - 1 / x;
- if (d > max_defect)
- {
- max_defect = d;
- max_defect_x = x;
- }
- if (d < min_defect)
- {
- min_defect = d;
- min_defect_x = x;
- }
- y2d0 = floor (y1 * x * (1LL << 60-16));
- y2d1 = (int) (long long) y2d0;
- y2d = - floor ((y1 - y0 / (1<<30-14)) * y2d1) / (1LL<<44);
- d2 = y1 + y2d - 1/x;
- if (d2 > max_defect2)
- {
- max_defect2 = d2;
- max_defect2_x = x;
- }
- if (d2 < min_defect2)
- {
- min_defect2 = d2;
- min_defect2_x = x;
- }
- /* zero times anything is trivially zero. */
- note_defect3 ((1 << CUTOFF_BITS) - 1, d2, y2d, x);
- note_defect3 (1 << CUTOFF_BITS, d2, y2d, x);
- note_defect3 ((1U << 31) - (1 << CUTOFF_BITS), d2, y2d, x);
- note_defect3 ((1U << 31) - 1, d2, y2d, x);
- note_defect3 (-1, d2, y2d, x);
- note_defect3 (-(1 << CUTOFF_BITS), d2, y2d, x);
- note_defect3 ((1U << 31) - (1 << CUTOFF_BITS) + 1, d2, y2d, x);
- note_defect3 (-(1U << 31), d2, y2d, x);
- return d;
-}
-
-int
-main ()
-{
- int i;
- unsigned char factors[N_ENTRIES];
- short constants[N_ENTRIES];
- int steps = N_ENTRIES / 2;
- double step = 1. / steps;
- double eps30 = 1. / (1024 * 1024 * 1024);
-
- for (i = 0; i < N_ENTRIES; i++)
- {
- double x_low = (i < steps ? 1. : -3.) + i * step;
- double x_high = x_low + step - eps30;
- double x_med;
- int factor, constant;
- double low_defect, med_defect, high_defect, max_defect;
-
- factor = (1./x_low- 1./x_high) / step * 256. + 0.5;
- if (factor == 256)
- factor = 255;
- factors[i] = factor;
- /* Use minimum of error function for x_med. */
- x_med = sqrt (256./factor);
- if (x_low < 0)
- x_med = - x_med;
- low_defect = 1. / x_low + x_low * factor / 256.;
- high_defect = 1. / x_high + x_high * factor / 256.;
- med_defect = 1. / x_med + x_med * factor / 256.;
- max_defect
- = ((low_defect > high_defect) ^ (x_med < 0)) ? low_defect : high_defect;
- constant = (med_defect + max_defect) * 0.5 * 16384. + 0.5;
- if (constant < -32768 || constant > 32767)
- abort ();
- constants[i] = constant;
- calc_defect (x_low, constant, factor);
- calc_defect (x_med, constant, factor);
- calc_defect (x_high, constant, factor);
- }
- printf ("/* This table has been generated by divtab.cc .\n");
- printf ("Defects for bias %d:\n", BIAS);
- printf (" Max defect: %e at %e\n", max_defect, max_defect_x);
- printf (" Min defect: %e at %e\n", min_defect, min_defect_x);
- printf (" Max 2nd step defect: %e at %e\n", max_defect2, max_defect2_x);
- printf (" Min 2nd step defect: %e at %e\n", min_defect2, min_defect2_x);
- printf (" Max div defect: %e at %d:%e\n", max_defect3, max_defect3_val,
- max_defect3_x);
- printf (" Min div defect: %e at %d:%e\n", min_defect3, min_defect3_val,
- min_defect3_x);
- printf (" Defect at 1: %e\n",
- calc_defect (1., constants[0], factors[0]));
- printf (" Defect at -2: %e */\n",
- calc_defect (-2., constants[steps], factors[steps]));
- printf ("\t.section\t.rodata\n");
- printf ("\t.balign 2\n");
- printf ("/* negative division constants */\n");
- for (i = steps; i < 2 * steps; i++)
- printf ("\t.word\t%d\n", constants[i]);
- printf ("/* negative division factors */\n");
- for (i = steps; i < 2*steps; i++)
- printf ("\t.byte\t%d\n", factors[i]);
- printf ("\t.skip %d\n", steps);
- printf ("\t.global GLOBAL(div_table):\n");
- printf ("GLOBAL(div_table):\n");
- printf ("\t.skip %d\n", steps);
- printf ("/* positive division factors */\n");
- for (i = 0; i < steps; i++)
- printf ("\t.byte\t%d\n", factors[i]);
- printf ("/* positive division constants */\n");
- for (i = 0; i < steps; i++)
- printf ("\t.word\t%d\n", constants[i]);
- exit (0);
-}
