1/* Copyright (C) 2004-2020 Free Software Foundation, Inc. 2 3This file is free software; you can redistribute it and/or modify it 4under the terms of the GNU General Public License as published by the 5Free Software Foundation; either version 3, or (at your option) any 6later version. 7 8This file is distributed in the hope that it will be useful, but 9WITHOUT ANY WARRANTY; without even the implied warranty of 10MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11General Public License for more details. 12 13Under Section 7 of GPL version 3, you are granted additional 14permissions described in the GCC Runtime Library Exception, version 153.1, as published by the Free Software Foundation. 16 17You should have received a copy of the GNU General Public License and 18a copy of the GCC Runtime Library Exception along with this program; 19see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 20<http://www.gnu.org/licenses/>. */ 21 22/* Calculate division table for SH2..4 integer division 23 Contributed by Joern Rernnecke 24 joern.rennecke@superh.com */ 25 26#include <stdio.h> 27#include <math.h> 28 29int 30main () 31{ 32 int i, j; 33 double q, r, err, max_err = 0, max_s_err = 0; 34 35 puts("/* This table has been generated by divtab-sh4.c. */"); 36 puts ("\t.balign 4"); 37 puts ("LOCAL(div_table_clz):"); 38 /* output some dummy number for 1/0. */ 39 printf ("\t.byte\t%d\n", 0); 40 for (i = 1; i <= 128; i++) 41 { 42 int n = 0; 43 if (i == 128) 44 puts ("\ 45/* Lookup table translating positive divisor to index into table of\n\ 46 normalized inverse. N.B. the '0' entry is also the last entry of the\n\ 47 previous table, and causes an unaligned access for division by zero. */\n\ 48LOCAL(div_table_ix):"); 49 for (j = i; j <= 128; j += j) 50 n++; 51 printf ("\t.byte\t%d\n", n - 7); 52 } 53 for (i = 1; i <= 128; i++) 54 { 55 j = i < 0 ? -i : i; 56 while (j < 128) 57 j += j; 58 printf ("\t.byte\t%d\n", j * 2 - 96*4); 59 } 60 puts("\ 61/* 1/64 .. 1/127, normalized. There is an implicit leading 1 in bit 32. */\n\ 62 .balign 4\n\ 63LOCAL(zero_l):"); 64 for (i = 64; i < 128; i++) 65 { 66 if (i == 96) 67 puts ("LOCAL(div_table):"); 68 q = 4.*(1<<30)*128/i; 69 r = ceil (q); 70 /* The value for 64 is actually differently scaled that it would 71 appear from this calculation. The implicit part is %01, not 10. 72 Still, since the value in the table is 0 either way, this 73 doesn't matter here. Still, the 1/64 entry is effectively a 1/128 74 entry. */ 75 printf ("\t.long\t0x%X\n", (unsigned) r); 76 err = r - q; 77 if (err > max_err) 78 max_err = err; 79 err = err * i / 128; 80 if (err > max_s_err) 81 max_s_err = err; 82 } 83 printf ("\t/* maximum error: %f scaled: %f*/\n", max_err, max_s_err); 84 exit (0); 85} 86