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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /gcc/config/sh/divtab-sh4.c | |
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Diffstat (limited to 'gcc/config/sh/divtab-sh4.c')
-rw-r--r-- | gcc/config/sh/divtab-sh4.c | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/gcc/config/sh/divtab-sh4.c b/gcc/config/sh/divtab-sh4.c new file mode 100644 index 000000000..758508130 --- /dev/null +++ b/gcc/config/sh/divtab-sh4.c @@ -0,0 +1,85 @@ +/* Copyright (C) 2004, 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 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 SH2..4 integer division + Contributed by Joern Rernnecke + joern.rennecke@superh.com */ + +#include <stdio.h> +#include <math.h> + +int +main () +{ + int i, j; + double q, r, err, max_err = 0, max_s_err = 0; + + puts("/* This table has been generated by divtab-sh4.c. */"); + puts ("\t.balign 4"); + puts ("LOCAL(div_table_clz):"); + /* output some dummy number for 1/0. */ + printf ("\t.byte\t%d\n", 0); + for (i = 1; i <= 128; i++) + { + int n = 0; + if (i == 128) + puts ("\ +/* Lookup table translating positive divisor to index into table of\n\ + normalized inverse. N.B. the '0' entry is also the last entry of the\n\ + previous table, and causes an unaligned access for division by zero. */\n\ +LOCAL(div_table_ix):"); + for (j = i; j <= 128; j += j) + n++; + printf ("\t.byte\t%d\n", n - 7); + } + for (i = 1; i <= 128; i++) + { + j = i < 0 ? -i : i; + while (j < 128) + j += j; + printf ("\t.byte\t%d\n", j * 2 - 96*4); + } + puts("\ +/* 1/64 .. 1/127, normalized. There is an implicit leading 1 in bit 32. */\n\ + .balign 4\n\ +LOCAL(zero_l):"); + for (i = 64; i < 128; i++) + { + if (i == 96) + puts ("LOCAL(div_table):"); + q = 4.*(1<<30)*128/i; + r = ceil (q); + /* The value for 64 is actually differently scaled that it would + appear from this calculation. The implicit part is %01, not 10. + Still, since the value in the table is 0 either way, this + doesn't matter here. Still, the 1/64 entry is effectively a 1/128 + entry. */ + printf ("\t.long\t0x%X\n", (unsigned) r); + err = r - q; + if (err > max_err) + max_err = err; + err = err * i / 128; + if (err > max_s_err) + max_s_err = err; + } + printf ("\t/* maximum error: %f scaled: %f*/\n", max_err, max_s_err); + exit (0); +} |