1/* Generic signed 32 bit modulo implementation. 2 Copyright (C) 2009-2015 Free Software Foundation, Inc. 3 Contributed by Embecosm on behalf of Adapteva, Inc. 4 5This file is part of GCC. 6 7This file is free software; you can redistribute it and/or modify it 8under the terms of the GNU General Public License as published by the 9Free Software Foundation; either version 3, or (at your option) any 10later version. 11 12This file is distributed in the hope that it will be useful, but 13WITHOUT ANY WARRANTY; without even the implied warranty of 14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15General Public License for more details. 16 17Under Section 7 of GPL version 3, you are granted additional 18permissions described in the GCC Runtime Library Exception, version 193.1, as published by the Free Software Foundation. 20 21You should have received a copy of the GNU General Public License and 22a copy of the GCC Runtime Library Exception along with this program; 23see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24<http://www.gnu.org/licenses/>. */ 25 26typedef union { unsigned int i; float f; } fu; 27 28unsigned int __modsi3 (unsigned int a, unsigned int b); 29 30unsigned int 31__modsi3 (unsigned int a, unsigned int b) 32{ 33 unsigned int sign = (int) a >> 31; 34 unsigned int d, t, s0, s1, s2, r0, r1; 35 fu u0, u1, u2, u1b, u2b; 36 37 a = abs (a); 38 b = abs (b); 39 40 if (b > a) 41 goto ret_a; 42 43 /* Compute difference in number of bits in S0. */ 44 u0.i = 0x40000000; 45 u1b.i = u2b.i = u0.i; 46 u1.i = a; 47 u2.i = b; 48 u1.i = a | u0.i; 49 t = 0x4b800000 | ((a >> 23) & 0xffff); 50 if (a >> 23) 51 { 52 u1.i = t; 53 u1b.i = 0x4b800000; 54 } 55 u2.i = b | u0.i; 56 t = 0x4b800000 | ((b >> 23) & 0xffff); 57 if (b >> 23) 58 { 59 u2.i = t; 60 u2b.i = 0x4b800000; 61 } 62 u1.f = u1.f - u1b.f; 63 u2.f = u2.f - u2b.f; 64 s1 = u1.i >> 23; 65 s2 = u2.i >> 23; 66 s0 = s1 - s2; 67 68#define STEP(n) case n: d = b << n; t = a - d; if (t <= a) a = t; 69 switch (s0) 70 { 71 STEP (31) 72 STEP (30) 73 STEP (29) 74 STEP (28) 75 STEP (27) 76 STEP (26) 77 STEP (25) 78 STEP (24) 79 STEP (23) 80 STEP (22) 81 STEP (21) 82 STEP (20) 83 STEP (19) 84 STEP (18) 85 STEP (17) 86 STEP (16) 87 STEP (15) 88 STEP (14) 89 STEP (13) 90 STEP (12) 91 STEP (11) 92 STEP (10) 93 STEP (9) 94 STEP (8) 95 STEP (7) 96 STEP (6) 97 STEP (5) 98 STEP (4) 99 STEP (3) 100 STEP (2) 101 STEP (1) 102 STEP (0) 103 } 104 ret_a: 105 return (a ^ sign) - sign; 106} 107